OT: Lightning surges [Archive]

Dale Farmer

08-05-2003, 04:04 PM

Jay Levitt wrote:

> This is nothing to do with audio, but since there are plenty of people
> here who know about electricity...
>
> Twice this summer, I've lost equipment during a thunderstorm. Last
> week, I got a surge bad enough to not only fry my garage door opener but
> shatter the bulb! I have whole-house protectors at the service entrance
> (Cutler-Hammer CHSP 3-way), and some equipment is on power-strip surge
> protectors as well. All of these protectors still have their
> "protected" light lit. A few breakers did trip, which is odd - as I
> understand it, most surges are too short to trip a breaker.
>
> The power company wasn't aware of any strikes in my area. Is it
> possible for a nearby ground strike to somehow induce a surge in my
> power lines, bypassing the surge protectors?
>
> --
> Jay Levitt |
> Wellesley, MA | Hi!
> Faster: jay at jay dot eff-em | Where are we going?
> http://www.jay.fm | Why am I in this handbasket?

Any lightning protection system is only as good as the electrical
grounding
system it is connected too. Hire someone competent to come in and evaluate

your grounding system. That is the foundation piece, and a so so protection

system with an excellent ground is better than the best whiz-bang device
with
a crappy ground.
WIth the weather system crapping on the northeast right now, lighting
risk
is rather high for the next week or so. One thing you can do is check and
tighten all the ground wire connections from your power panel to the ground
system. ( Which is probably your water pipe. )

--Dale

Chris Hornbeck

08-05-2003, 05:51 PM

On Tue, 5 Aug 2003 15:07:55 -0400, Jay Levitt <jay+news@jay.fm> wrote:

>The power company wasn't aware of any strikes in my area.

Why would they?

> Is it
>possible for a nearby ground strike to somehow induce a surge in my
>power lines, bypassing the surge protectors?

Yes. The EMP from a million amperes current is often more of a
threat than the direct conduction. Good lightning protection for
modern electronics must include awareness of wiring, signal
and power, as antennas.

Fortunately, any effort expended here also helps to minimize
RFI, power switching and light dimmer, etc. noise problems.
Win-win.

Chris Hornbeck,
guyville{at}aristotle{dot}net

Kurt Albershardt

08-05-2003, 06:13 PM

Dale Farmer wrote:
>
>
> Any lightning protection system is only as good as the electrical
> grounding system it is connected too. Hire someone competent to come
> in and evaluate your grounding system. That is the foundation piece,
> and a so so protection system with an excellent ground is better than
> the best whiz-bang device with a crappy ground.

Yes, yes, yes, yes. I can't stress this enough.

> One thing you can do is check and
> tighten all the ground wire connections from your power panel to the ground
> system. ( Which is probably your water pipe. )

Unlikely a recent inspection would tolerate water pipe grounding (at
least in any of the jurisdictions I've worked under.)

Kurt Albershardt

08-05-2003, 06:16 PM

Jay Levitt wrote:

> In article <1060118808.696787@nnrp2.phx1.gblx.net>, kurt@nv.net says...
>
>> Under $50 for an LA302 http://www.deltala.com/ will dissipate most of
>> the problems.
>
>
> Is this actually an improvement over a whole-house surge suppressors?
> Cutler-Hammer sells both suppressors and arrestors; they call their
> suppressors "best" protection, while they call their arrestors "good".
> I'm a software guy, so any explanation or pointers would be helpful... I
> can find surprisingly little info via Google.

If the Cutler-Hammer device uses MOVs it won't provide the same level of
lightning protection as the SOVs used in the Delta product. MOVs are
designed for a different surge profile and also degrade over time from
small surges.

http://www.deltala.com/whydelta.htm and http://www.deltala.com/how.htm
explain some of this.

Dale Farmer

08-05-2003, 07:34 PM

Kurt Albershardt wrote:

> Dale Farmer wrote:
> >
> >
> > Any lightning protection system is only as good as the electrical
> > grounding system it is connected too. Hire someone competent to come
> > in and evaluate your grounding system. That is the foundation piece,
> > and a so so protection system with an excellent ground is better than
> > the best whiz-bang device with a crappy ground.
>
> Yes, yes, yes, yes. I can't stress this enough.
>
> > One thing you can do is check and
> > tighten all the ground wire connections from your power panel to the ground
> > system. ( Which is probably your water pipe. )
>
> Unlikely a recent inspection would tolerate water pipe grounding (at
> least in any of the jurisdictions I've worked under.)

Most recent NEC I have handy is the 1993 edition, and water pipe
grounding at the building entrance was allowable then. I suppose I ought
to bite the bullet and buy a current edition one of these days.
ANother important thing to remember is that the electrical code
requirements are the minimums, not best practice. If an electrician brags
that all his/her work meets the electrical code, then what they are really
saying is that their work is just adequate for not setting the building
on fire. This is also true of most all of the other building codes, they
are minimum safe levels.
For a recording studio you want to exceed the building code
minimums by such a large margin that the inspector can just glance
at the installation and have no doubt that it safely exceeds the standards.
As for it being updated to current code in 2001, it depends on just
which edition of the code, and are their any local variances in your
town. A ground that meets current electrical code is probably not
sufficient to ground out the lightning surges that your protector dumps
onto it, fast enough to protect all your gear.
Tell the installer that you want a ground system that is sufficient for
a lightning rod installation. ( typically they dig a trench around the
building, driving in ground stakes every ten feet or so, and the ground
stakes are welded to a heavy gauge braided cable, which is also
buried in the trench. This is also attached to building steel, the re-bar
in the cement of the building and foundation, and the building power
ground terminal, making up the grounding system. Never done a
lightning rod install myself, so don't quote me on that.

--Dale

Scott Dorsey

08-05-2003, 10:32 PM

Kurt Albershardt <kurt@nv.net> wrote:
>Dale Farmer wrote:
>
>> One thing you can do is check and
>> tighten all the ground wire connections from your power panel to the ground
>> system. ( Which is probably your water pipe. )
>
>Unlikely a recent inspection would tolerate water pipe grounding (at
>least in any of the jurisdictions I've worked under.)

The NEC hasn't allowed water pipe grounding since the sixties. BUT, it
does require that the water system be bonded to the house ground at
one point. If this goes wrong, you can get all kinds of weird problems.

But yes, making sure grounds is good is never a bad idea. And if the
existing ground system is insufficient (and you can talk first to the
local inspector and explain what has been happening to him, and secondly
to an outfit the specializes in lightning protection), it's not that
difficult to add onto an existing ground rod to make a cleaner and lower
impedance ground.

Ground impedance at very high frequencies is a big issue, which is why
the ground wire has to go from the panel straight to the rod without
any loops or kinks along the way. Lightning is a very fast risetime
pulse, so you need to think about stuff in the MHz region and not just
DC.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

w_tom

08-06-2003, 07:25 AM

Code describes earthing for human safety. Same ground may
be woefully insufficient for earthing surges.

First, follow the connection from each AC mains wire,
through Cutler Hammer, to earth ground. How long is that
distance? If sharp bends, splices, through metallic conduit,
or bundled with other wires, then positive effects of the
Cutler Hammer will be negated. Yes, that earth ground wire
must be separated from all other wires.

Earthing is 'the' most critical aspect in surge protection
as so many others have already posted. Earthing by a good
electrician may be sufficient for human safety but not
sufficient for surge protection. Surge protectors are simple
science. Nothing advanced or magical about them. Earthing
determines surge protection. Details are provided in two
previous discussions in the newsgroup misc.rural:
Storm and Lightning damage in the country 28 Jul 2002
Lightning Nightmares!! 10 Aug 2002
http://tinyurl.com/ghgv or http://tinyurl.com/ghgm

Code does not require earthing to be enhanced for surge
protection. Earthing system must exceed code requirements.
Even conductivity of earth can be poor - insufficient for
surge protection - but more than sufficient for code. For
example, if earthing in sand, then the 'code required' earth
ground will be woefully insufficient. A surge protector is
only as effective as its earth ground.

Jay Levitt wrote:
> In article <bgovp6$nqs$1@panix2.panix.com>, kludge@panix.com says...
> > Is your service entrance ground good?
> It *should* be, in that the whole house was rewired in 2001 to then-
> current Massachusetts code, and the electrical inspector for Wellesley
> is a bit of a stickler, and made us go farther than code in a few
> places. How can I check?

Roger W. Norman

08-06-2003, 07:44 AM

There are arc triggered breakers that see a "serious" drain on a system,
like a unit frying, and do their job of breaking. Simple replacements for
the panel, and although I think it would work for outside events, it's
principally designed to stop arc from dangerous internal circuits. I don't
know what it would do if it saw too much current coming in.

Plus, were you home when this happened? Do you know how close the strike
was? Even some of our household equipment and computers and such are
effected by strikes that can set off a local micro "EMP" burst from 70
million volts coming close. This would certainly bypass any electronics
used to monitor/condition/interrupt the power as it's a physical phenomena
not reduced to using wires.

Other than that, I did have a field problem in that our actual electrical
grid was somehow reduced to not being able to handle even the lightest
electrical storm, of which I complained to my friend/PEPCO employee who
happened to be the guy that redesigned the grid, so he spent maybe a week
here about (stopping over for lunch and that damned RUSH everyday) and
redesigned the grid and it's been pretty darned good for the past maybe 7
years. So I'd suggest that you find someone at the power company who will
come over and take a look at what you're running, give him any documentation
of what's been happening, and I'll bet somebody will get the grid right. I
mean, hell, most of these engineers aren't doing anything anyway because the
infrastructure is already built. Doesn't hurt, however, to have a friend
that just happens to do that for a living.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Jay Levitt" <jay+news@jay.fm> wrote in message
news:MPG.1999ca81cacb6b859899ea@news-east.giganews.com...
> This is nothing to do with audio, but since there are plenty of people
> here who know about electricity...
>
> Twice this summer, I've lost equipment during a thunderstorm. Last
> week, I got a surge bad enough to not only fry my garage door opener but
> shatter the bulb! I have whole-house protectors at the service entrance
> (Cutler-Hammer CHSP 3-way), and some equipment is on power-strip surge
> protectors as well. All of these protectors still have their
> "protected" light lit. A few breakers did trip, which is odd - as I
> understand it, most surges are too short to trip a breaker.
>
> The power company wasn't aware of any strikes in my area. Is it
> possible for a nearby ground strike to somehow induce a surge in my
> power lines, bypassing the surge protectors?
>
> --
> Jay Levitt |
> Wellesley, MA | Hi!
> Faster: jay at jay dot eff-em | Where are we going?
> http://www.jay.fm | Why am I in this handbasket?

Scott Dorsey

08-06-2003, 08:05 AM

Roger W. Norman <rnorman@starpower.net> wrote:
>There are arc triggered breakers that see a "serious" drain on a system,
>like a unit frying, and do their job of breaking. Simple replacements for
>the panel, and although I think it would work for outside events, it's
>principally designed to stop arc from dangerous internal circuits. I don't
>know what it would do if it saw too much current coming in.

I think those arc-triggered breakers look for high frequency trash from an
arc and cut the circuit off when it sees that. Touch lamps will also make
them shut off, I do know. I'm not sure I like the idea, and I don't think
they will act fast enough to do any real good in this case.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Roger W. Norman

08-06-2003, 08:10 AM

Nothing will kill 70 million volts hitting any type of wire coming into your
house, but it's most likely near strikes that are your problem. If 70
million volts hit a typical grid's wires, it would be clamped down on pretty
quickly and then you'd get your grid back within seconds. If you get hit
with about three quick blackouts, then you're done, but still, it's the grid
doing the clamping, not anything within your house. You can't suppress that
many volts on a direct hit to any line within a couple of blocks from you.
These suppressors/arrestors are depending on the grid itself clamping down,
picking back up after some transformer took the majority of the hit (really
amazing blue light - like a small nuke).

What type of location do you live at? I'm about as high here (sea level
wise, you smart asses) as any house around for about 2 miles, that being I'm
well over most everything else around my area and nothing higher for a
couple of miles around. **** comes close here, thus my two extra grounding
rods, one for my woodshop and one for the pool equipment, both number 6 8'
rods buried all the way into the earth. If you're getting hits close enough
to do that type of damage you might be better off running well grounded
lightning rods on your roof.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Jay Levitt" <jay+news@jay.fm> wrote in message
news:MPG.1999f27c1e9b95cd9899eb@news-east.giganews.com...
> In article <1060118808.696787@nnrp2.phx1.gblx.net>, kurt@nv.net says...
> > Under $50 for an LA302 http://www.deltala.com/ will dissipate most of
> > the problems.
>
> Is this actually an improvement over a whole-house surge suppressors?
> Cutler-Hammer sells both suppressors and arrestors; they call their
> suppressors "best" protection, while they call their arrestors "good".
> I'm a software guy, so any explanation or pointers would be helpful... I
> can find surprisingly little info via Google.
>
> --
> Jay Levitt |
> Wellesley, MA | Hi!
> Faster: jay at jay dot eff-em | Where are we going?
> http://www.jay.fm | Why am I in this handbasket?

Roger W. Norman

08-06-2003, 08:23 AM

****, in my original grounding system I had an old fused 60 amp box that got
upgraded to a 200 amp breaker box, but the idiots that set it up, although
running a #10 grounding rod (hardly big enough nor long enough), also left
the box tied to the water pipe feeding the house, of which it was gavalnized
steel. In order to get the correct ground setup I had to decide to cut the
ground on the waterpipe and go with the grounding rod. I've since pulled
that one and put in three #6 8' grounding rods, basically establishing three
separate electrical services throughout the property (household ground does
not go to the woodshop nor the pool).

There are some things you can do within the confines of your own property to
get better power. If the power company won't offer you better power, then
you may be stuck with doing some of this yourself. You can get air powered
palm nailers that will take a #6 8' copper rod and put it 7' 11" into the
ground in about 15 seconds. I think that's the thing that scares most
people from doing their own grounding work. Trying to drive the rod in.
Short work with the right tools.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Kurt Albershardt" <kurt@nv.net> wrote in message
news:1060128750.843378@nnrp2.phx1.gblx.net...
> Dale Farmer wrote:
> >
> >
> > Any lightning protection system is only as good as the electrical
> > grounding system it is connected too. Hire someone competent to come
> > in and evaluate your grounding system. That is the foundation piece,
> > and a so so protection system with an excellent ground is better than
> > the best whiz-bang device with a crappy ground.
>
> Yes, yes, yes, yes. I can't stress this enough.
>
>
>
> > One thing you can do is check and
> > tighten all the ground wire connections from your power panel to the
ground
> > system. ( Which is probably your water pipe. )
>
> Unlikely a recent inspection would tolerate water pipe grounding (at
> least in any of the jurisdictions I've worked under.)
>
>
>
>

Roger W. Norman

08-06-2003, 08:35 AM

****, I'm answering every post. As far as electricians who brag they
absolutely have to meet code to accept a job that might be under the
inspector's wire, I had an electrician in last year who took my design for
the sub-panel and circuits outside for the woodshop and pool, and basically
gave me his stamp of approval as long as I dug a 12" trench a shovel wide
for the entire 125' of 60 Amp 6/2 cable necessary to do the job. This was
last year and I hurt my back, so I hired his "laborers" to do the job. I've
had to re-dig up that job because the last two thirds, done by the
electrician's helpers, was only 4 to 6" deep and he mounted electrical that
shouldn't, by code, be closer than 5' to the pool DIRECTLY ONTO THE POOL.

Now I'm a kinda hands on guy, so when I saw this I called my Pepco friend
back over, and I've since redone the electrical to meet code even if an
inspector isn't coming over. But in some cases, maybe an inspector is the
best way to get the local utility to do it's job. If not, prepare to learn
something about electricity and then make some design changes. The concept
of a field wide grounding system isn't that big of a deal. It takes less
time than the damage that can ensue costs.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Dale Farmer" <Dale@cybercom.net> wrote in message
news:3F305B16.161DD31B@cybercom.net...
>
>
> Kurt Albershardt wrote:
>
> > Dale Farmer wrote:
> > >
> > >
> > > Any lightning protection system is only as good as the electrical
> > > grounding system it is connected too. Hire someone competent to come
> > > in and evaluate your grounding system. That is the foundation piece,
> > > and a so so protection system with an excellent ground is better than
> > > the best whiz-bang device with a crappy ground.
> >
> > Yes, yes, yes, yes. I can't stress this enough.
> >
> > > One thing you can do is check and
> > > tighten all the ground wire connections from your power panel to the
ground
> > > system. ( Which is probably your water pipe. )
> >
> > Unlikely a recent inspection would tolerate water pipe grounding (at
> > least in any of the jurisdictions I've worked under.)
>
> Most recent NEC I have handy is the 1993 edition, and water pipe
> grounding at the building entrance was allowable then. I suppose I ought
> to bite the bullet and buy a current edition one of these days.
> ANother important thing to remember is that the electrical code
> requirements are the minimums, not best practice. If an electrician brags
> that all his/her work meets the electrical code, then what they are really
> saying is that their work is just adequate for not setting the building
> on fire. This is also true of most all of the other building codes, they
> are minimum safe levels.
> For a recording studio you want to exceed the building code
> minimums by such a large margin that the inspector can just glance
> at the installation and have no doubt that it safely exceeds the
standards.
> As for it being updated to current code in 2001, it depends on just
> which edition of the code, and are their any local variances in your
> town. A ground that meets current electrical code is probably not
> sufficient to ground out the lightning surges that your protector dumps
> onto it, fast enough to protect all your gear.
> Tell the installer that you want a ground system that is sufficient
for
> a lightning rod installation. ( typically they dig a trench around the
> building, driving in ground stakes every ten feet or so, and the ground
> stakes are welded to a heavy gauge braided cable, which is also
> buried in the trench. This is also attached to building steel, the re-bar
> in the cement of the building and foundation, and the building power
> ground terminal, making up the grounding system. Never done a
> lightning rod install myself, so don't quote me on that.
>
> --Dale
>
>

Roger W. Norman

08-06-2003, 08:38 AM

Neither did I know how they'd respond. Seems good protection should be
available from the gozintas and gozoutas. Once something serious gets into
the gozintas, it's too late to protect the gozoutas. Like Herman's Hermits
said, This Door Swings Both Ways.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Scott Dorsey" <kludge@panix.com> wrote in message
news:bgr1uu$8mm$1@panix2.panix.com...
> Roger W. Norman <rnorman@starpower.net> wrote:
> >There are arc triggered breakers that see a "serious" drain on a system,
> >like a unit frying, and do their job of breaking. Simple replacements
for
> >the panel, and although I think it would work for outside events, it's
> >principally designed to stop arc from dangerous internal circuits. I
don't
> >know what it would do if it saw too much current coming in.
>
> I think those arc-triggered breakers look for high frequency trash from an
> arc and cut the circuit off when it sees that. Touch lamps will also make
> them shut off, I do know. I'm not sure I like the idea, and I don't think
> they will act fast enough to do any real good in this case.
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey

08-06-2003, 09:21 AM

Roger W. Norman <rnorman@starpower.net> wrote:
>
>Now I'm a kinda hands on guy, so when I saw this I called my Pepco friend
>back over, and I've since redone the electrical to meet code even if an
>inspector isn't coming over. But in some cases, maybe an inspector is the
>best way to get the local utility to do it's job. If not, prepare to learn
>something about electricity and then make some design changes. The concept
>of a field wide grounding system isn't that big of a deal. It takes less
>time than the damage that can ensue costs.

A lot of electricians just plain don't know the code outside the little
area where they normally work. The code is big and it's pretty dense,
and it can be difficult to read because it explains what to do but never
why it's necessary.

If he's never looked at the swimming pool section of the code, he might
very well not know that this is a bad thing to do.

I know that I have had a lot of nightmares dealing with licensed electricians
at festival gigs and film shoots who have never used remote generators and
don't know about the varied and unusual grounding regulations for remote power
systems. (Regulations that do make sense if you sit down and really think
about them, but which can seem alarming if you don't. I had a lot of fun
explaining to one fellow at the Potomac festival last year that his generator
had to run ungrounded and that tying it to a ground rod was a code violation,
but that if it was connected to a fixed trailer it would have to be grounded).
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Dale Farmer

08-06-2003, 10:05 AM

"Roger W. Norman" wrote:

> There are arc triggered breakers that see a "serious" drain on a system,
> like a unit frying, and do their job of breaking. Simple replacements for
> the panel, and although I think it would work for outside events, it's
> principally designed to stop arc from dangerous internal circuits. I don't
> know what it would do if it saw too much current coming in.
>
> Plus, were you home when this happened? Do you know how close the strike
> was? Even some of our household equipment and computers and such are
> effected by strikes that can set off a local micro "EMP" burst from 70
> million volts coming close. This would certainly bypass any electronics
> used to monitor/condition/interrupt the power as it's a physical phenomena
> not reduced to using wires.
>
> Other than that, I did have a field problem in that our actual electrical
> grid was somehow reduced to not being able to handle even the lightest
> electrical storm, of which I complained to my friend/PEPCO employee who
> happened to be the guy that redesigned the grid, so he spent maybe a week
> here about (stopping over for lunch and that damned RUSH everyday) and
> redesigned the grid and it's been pretty darned good for the past maybe 7
> years. So I'd suggest that you find someone at the power company who will
> come over and take a look at what you're running, give him any documentation
> of what's been happening, and I'll bet somebody will get the grid right. I
> mean, hell, most of these engineers aren't doing anything anyway because the
> infrastructure is already built. Doesn't hurt, however, to have a friend
> that just happens to do that for a living.
>

Also understand that if the lightning bolt actually strikes your house, or
along
your particular street, then no matter what you install, all the electronics in
the
house are going to be fried. There is an unbelievably huge amount of energy
in a lightning bolt. When I was in the fire department, we always listened and
started getting ready when the dispatcher called out that there was a
thunderstorm was moving through the area.
When the lightning actually hit in a residential neighborhood, we could
count
on one to three attic fires along the street, usually right next door to each
other.
The lightning bolt would strike the neutral/ground conductor on the street
poles,
( this is one of the reasons that the nuetral/ground conductor on the street
poles
is the highest one on the pole. ) The current would race along the wire looking

for grounds to earth. This includes the ground rod in each home power panel.
But when the surge from the lightning bolt reaches the drip loop at the house,
the curves and loops would 'confuse' it. ( hand waving a lot of science I never

really understood anyway. ) and it would keep going in a straight line and blast

into the side of the house, where the anchor bolt was attached to the structure
of the house.
This would blow a hole in the side of the house where the anchor bolt
was, and ignite anything flammable in the vicinity. Since most folks have all
kinds of random, mostly flammable, junk in their attic, it would be burning
nicely by the time we arrived. Nothing beats the fun of climbing up onto
the roof of a burning house with a saw in the rain and cutting a vent hole
there, without falling off the roof, or through the roof into the fire.

What these protection devices do is protect your stuff from the lightning
strike that hits a little bit further away. You are at the mercy of the power
companies routing scheme there. And they are not going to change it for
your convenience. To really protect yourself the best, go to a building that
is in close enough to the city where all the utilities are buried.

--Dale

Scott Dorsey

08-06-2003, 11:41 AM

Dale Farmer <Dale@cybercom.net> wrote:
>But when the surge from the lightning bolt reaches the drip loop at the house,
>the curves and loops would 'confuse' it. ( hand waving a lot of science I never
>
>really understood anyway. ) and it would keep going in a straight line and blast
>
>into the side of the house, where the anchor bolt was attached to the structure
>of the house.

That loop forms an inductor, so it has a high impedance at high frequencies.
Remember we're talking about stuff in the MHz range here. So the air has a
lower impedance than the cable does and the current goes through the air
instead.

This is why we put a loop at the bottom of the antenna cables, to make
the impedance to a pulse going into the receiver much higher and encourage
the current to take another path.

> What these protection devices do is protect your stuff from the lightning
>strike that hits a little bit further away. You are at the mercy of the power
>companies routing scheme there. And they are not going to change it for
>your convenience. To really protect yourself the best, go to a building that
>is in close enough to the city where all the utilities are buried.

That doesn't guarantee anything, since lightning strikes to the ground can
still induce big ground currents as well as inducing trash in buried conduit
lines. It reduces the chances, but it doesn't eliminate it.

The good news is that your panel actually acts as a surge suppressor; anything
over around 6 KV will arc directly across the panel. So when we build surge
suppression into power supplies, we don't really have to worry about anything
over 6 KV.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

ScotFraser

08-06-2003, 02:47 PM

<< You can get air powered
palm nailers that will take a #6 8' copper rod and put it 7' 11" into the
ground in about 15 seconds. I think that's the thing that scares most
people from doing their own grounding work. Trying to drive the rod in.
Short work with the right tools. >>

Not where I live. There's solid rock about 4 feet down. Both studio ground rods
I've installed over the years just stopped right there & the biggest sledges in
the hands of the strongest guys on site just couldn't get it any further, while
completely mushrooming the top. So that's where we cut it off.

Scott Fraser

Stephen Sank

08-06-2003, 03:50 PM

OK, two questions-
1) Isn't there a heavy grounding wire to earth at each utility pole? If
not, why not?
2) In a breaker panel, every one I have seen has basically two overlaping
"trees" of copper, so that the two phases of 240v are within no more than
1.5 inches for quite a lot of surface area. Isn't air dielectric strength
about 1" per KV? Would that not make the panel a 1.5kv surge arrestor?

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"Scott Dorsey" <kludge@panix.com> wrote in message
news:bgrel7$m4d$1@panix2.panix.com...
> Dale Farmer <Dale@cybercom.net> wrote:
> >But when the surge from the lightning bolt reaches the drip loop at the
house,
> >the curves and loops would 'confuse' it. ( hand waving a lot of science
I never
> >
> >really understood anyway. ) and it would keep going in a straight line
and blast
> >
> >into the side of the house, where the anchor bolt was attached to the
structure
> >of the house.
>
> That loop forms an inductor, so it has a high impedance at high
frequencies.
> Remember we're talking about stuff in the MHz range here. So the air has
a
> lower impedance than the cable does and the current goes through the air
> instead.
>
> This is why we put a loop at the bottom of the antenna cables, to make
> the impedance to a pulse going into the receiver much higher and encourage
> the current to take another path.
>
> > What these protection devices do is protect your stuff from the
lightning
> >strike that hits a little bit further away. You are at the mercy of the
power
> >companies routing scheme there. And they are not going to change it for
> >your convenience. To really protect yourself the best, go to a building
that
> >is in close enough to the city where all the utilities are buried.
>
> That doesn't guarantee anything, since lightning strikes to the ground can
> still induce big ground currents as well as inducing trash in buried
conduit
> lines. It reduces the chances, but it doesn't eliminate it.
>
> The good news is that your panel actually acts as a surge suppressor;
anything
> over around 6 KV will arc directly across the panel. So when we build
surge
> suppression into power supplies, we don't really have to worry about
anything
> over 6 KV.
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

Jay Levitt

08-06-2003, 03:58 PM

In article <bgq0c0$lt0$1@panix2.panix.com>, kludge@panix.com says...
> Ground impedance at very high frequencies is a big issue, which is why
> the ground wire has to go from the panel straight to the rod without
> any loops or kinks along the way. Lightning is a very fast risetime
> pulse, so you need to think about stuff in the MHz region and not just
> DC.

Interesting and educational.. thanks. I realized that code is only a
minimum standard, but hadn't thought about the vast difference in
requirements between a safety ground and a lightning discharge.

The ground from my panel is not via the water pipe, although (as
mentioned elsewhere in the thread it's bonded to that, and in fact any
gaps in that (e.g. water filter, softener) have large jumpers.

The ground itself is a thick braided cable, 3/0 gauge if I'm reading the
smudged printing correctly. Oddly, I only see this cable going to one
of the two panels, and one is NOT a sub-panel of the other; perhaps the
ground is tied between them with regular Romex? These are 200-amp
panels, FWIW.

The other bad part is that the ground cable runs at LEAST 30 feet before
disappearing into a crawlspace. That doesn't seem like a good thing. I
suspect that this ground wire was not redone when the house was rewired,
so it could be as old as 1970, when the house was first wired (it used
to be a carriage house). Heck, it could be going nowhere at all
anymore.

Interestingly, nothing in my studio seems to have been damaged. I
assumed that was because of the Equitech isolation panel, but perhaps
it's actually because the studio has its own ground rod, which is much
more likely to be done correctly. That's all behind drywall, so I can't
see where it goes.

My electrician's had a family emergency, but when he gets back to work,
maybe he can shed some (battery-powered) light on the grounding system
here.

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

Jay Levitt

08-06-2003, 04:01 PM

In article <1060128926.743588@nnrp2.phx1.gblx.net>, kurt@nv.net says...
> If the Cutler-Hammer device uses MOVs it won't provide the same level of
> lightning protection as the SOVs used in the Delta product.

Interesting. According to their warranty guy, it does in fact use MOVs.
Maybe I should add a Delta, in addition to fixing the likely grounding
problems.

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

Jay Levitt

08-06-2003, 04:11 PM

In article <bgr09i$rta$1@bob.news.rcn.net>, rnorman@starpower.net
says...
> There are arc triggered breakers that see a "serious" drain on a system,
> like a unit frying, and do their job of breaking. Simple replacements for
> the panel, and although I think it would work for outside events, it's
> principally designed to stop arc from dangerous internal circuits. I don't
> know what it would do if it saw too much current coming in.

If these are what I'm thinking of, they are actually now required for
bedrooms as of 2002 or 2003. The electrician and I discussed installing
them in 2001 when we renovated, but at that point he felt they were
somewhat new, tripped way too easily, and that I shouldn't be a guinea
pig - better to wait for the second generation of equipment once
everyone else started installing these things en masse.

> Plus, were you home when this happened? Do you know how close the strike
> was? Even some of our household equipment and computers and such are
> effected by strikes that can set off a local micro "EMP" burst from 70
> million volts coming close. This would certainly bypass any electronics
> used to monitor/condition/interrupt the power as it's a physical phenomena
> not reduced to using wires.

I wasn't home. I didn't see any trees down near me. In fact, as
thunderstorms go, this seemed pretty tame. When I lived in Northern
Virginia, the forecast every day from May to October was "hot, hazy,
humid, chance of thundershowers", and we had some doozies, yet I never
lost a single piece of equipment. In New England we get maybe a dozen
storms a season, and here I have things frying left and right... that
was one reason I called the power company. I figured maybe they had
received multiple reports from customers, but no.

> So I'd suggest that you find someone at the power company who will
> come over and take a look at what you're running, give him any documentation
> of what's been happening, and I'll bet somebody will get the grid right.

Not a bad idea at all, once I straighten out the questionable grounding.
Wellesley has its own tiny power company, and I've talked to their
engineer on a few occasions for other reasons (most recently to figure
out why my lights were dimming on a 400-amp service when a 150A-LRA air
conditioner kicks in. Never did figure that out, but now I'm on my own
personal transformer secondary...)

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

Jay Levitt

08-06-2003, 04:17 PM

In article <bgr1pn$202$1@bob.news.rcn.net>, rnorman@starpower.net
says...
> What type of location do you live at? I'm about as high here (sea level
> wise, you smart asses) as any house around for about 2 miles, that being I'm
> well over most everything else around my area and nothing higher for a
> couple of miles around.

Not here. Wellesley is suburban, about 13 miles from Boston. It's
hilly, and I am up a bit from my street, but my roofline is about 20
feet lower than the house next door.

The service is underground on the property, but there are poles on the
street; I'm not sure if those are just phone and TV, or if the
electricity is also run there. There's one of those big canister
transformers on the pole, so unless those are also used in low-power
transmission, I'd guess that's the power line too.

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

Scott Dorsey

08-06-2003, 04:56 PM

ScotFraser <scotfraser@aol.com> wrote:
><< You can get air powered
>palm nailers that will take a #6 8' copper rod and put it 7' 11" into the
>ground in about 15 seconds. I think that's the thing that scares most
>people from doing their own grounding work. Trying to drive the rod in.
>Short work with the right tools. >>
>
>Not where I live. There's solid rock about 4 feet down. Both studio ground rods
>I've installed over the years just stopped right there & the biggest sledges in
>the hands of the strongest guys on site just couldn't get it any further, while
>completely mushrooming the top. So that's where we cut it off.

In places like this, sometimes burying ground systems inside cement slabs
can be a good solution. Cement is pretty conductive, and you can have a
very large surface area between the cement and the surrounding soil for
a good solid ground.

I also strongly recommend a percussion drill for putting ground rods in.
MUCH easier than a sledge in hard ground, especially if you have to put
dozens of rods in for an antenna system.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey

08-06-2003, 05:09 PM

Stephen Sank <bk11@thuntek.net> wrote:
>OK, two questions-
>1) Isn't there a heavy grounding wire to earth at each utility pole? If
>not, why not?

There are grounding wires at each point where there are lightning arrestors.
You do not want to ground the neutral all over the place or you will create
ground loops.

>2) In a breaker panel, every one I have seen has basically two overlaping
>"trees" of copper, so that the two phases of 240v are within no more than
>1.5 inches for quite a lot of surface area. Isn't air dielectric strength
>about 1" per KV? Would that not make the panel a 1.5kv surge arrestor?

It comes in around 6 KV between the individual phase bars on most designs.
Dielectric strength of air is lower than that, I believe.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey

08-06-2003, 05:20 PM

Jay Levitt <jay+news@jay.fm> wrote:
>
>The service is underground on the property, but there are poles on the
>street; I'm not sure if those are just phone and TV, or if the
>electricity is also run there. There's one of those big canister
>transformers on the pole, so unless those are also used in low-power
>transmission, I'd guess that's the power line too.

Okay, on the top of the pole is a crossbar with three uninsulated
aluminum wires. That's the 3KV feeder line.

Below that you'll see three uninsulated wires, or sometimes a bundle
of three insulated wires, attached to the pole with no crossbar. That
is 120/240V.

If you look at the transformers, you'll find they are between the 3KV
lines and the 120/240V lines. And you'll see taps from the 120/240V
to individual drops to houses.

Below the power lines on the pole you'll see phone lines, which are
big and thick and black and very different-looking than the power
lines. They have long and round metal cans for junctions and splices
occasionally along the line. Sometimes you will see short squat silver
metal cans for junctions in GTE-land, bolted to poles.

The cable TV line is even lower than that. Depending on where you
are, it can be one or two big thick black cables, sometimes with
helical grooves on the outside. The TV backbone is either hardline
or Heliax material depending on where you are, but you can tell the
difference between it and the phone stuff because the junction boxes
are very different.

All this stuff is probably illegal for me to tell you under the new
anti-terrorism laws, but it's lots of fun to walk around town looking
at poles.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Chris Hornbeck

08-06-2003, 05:38 PM

On Wed, 6 Aug 2003 15:50:53 -0600, "Stephen Sank" <bk11@thuntek.net>
wrote:

> Isn't air dielectric strength
>about 1" per KV? Would that not make the panel a 1.5kv surge arrestor?

Auto ignitions fire at 12 to 20 KV, so the air in distributors,
etc, must withstand much more. Looking at a list of insulators,
puncture voltage expressed in volts per mil (.001") varies from
40 (porcelain!?) to 5600 (mica). Air is listed with no value
given.

Of course, I have been wrong a lot today.

Chris Hornbeck,

But I'd be offended if the listener wanted to undo something that I had
done deliberately. Not offended enough to buy the record back, mind you...
--scott

Mike Rivers

08-07-2003, 04:54 AM

In article <MPG.199b4716641401b09899ef@news-east.giganews.com> jay+news@jay.fm writes:

> When I lived in Northern
> Virginia, the forecast every day from May to October was "hot, hazy,
> humid, chance of thundershowers", and we had some doozies, yet I never
> lost a single piece of equipment.

That's where I am, that's what the forecast is, and that's what we
get. I lost a gutter once, but that was because a tree fell on it.

--
I'm really Mike Rivers - (mrivers@d-and-d.com)

Scott Dorsey

08-07-2003, 10:24 AM

Jay Levitt <jay+news@jay.fm> wrote:
>
>The ground itself is a thick braided cable, 3/0 gauge if I'm reading the
>smudged printing correctly. Oddly, I only see this cable going to one
>of the two panels, and one is NOT a sub-panel of the other; perhaps the
>ground is tied between them with regular Romex? These are 200-amp
>panels, FWIW.

The code says that each individual service needs to be grounded, so that
second panel should have a connection to a ground. Pull the cover off
and look inside and see if it doesn't.

It might be done with insulated wire, if the installing electrician had
some lying around, but that is not necessary or useful and costs more.

>The other bad part is that the ground cable runs at LEAST 30 feet before
>disappearing into a crawlspace. That doesn't seem like a good thing. I
>suspect that this ground wire was not redone when the house was rewired,
>so it could be as old as 1970, when the house was first wired (it used
>to be a carriage house). Heck, it could be going nowhere at all
>anymore.

The code says this is okay, as long as "the ground electrode is as near
as practicable to and preferably in the same area as the grounding conductor
connection to the system" (250-26C).

>Interestingly, nothing in my studio seems to have been damaged. I
>assumed that was because of the Equitech isolation panel, but perhaps
>it's actually because the studio has its own ground rod, which is much
>more likely to be done correctly. That's all behind drywall, so I can't
>see where it goes.

The isolation systems provide some isolation from trash on the power
lines, but they don't do anything about polluted grounds.

Does the studio have a seperate service? If so, it should have an individual
ground.

>My electrician's had a family emergency, but when he gets back to work,
>maybe he can shed some (battery-powered) light on the grounding system
>here.

Go to the bookstore and get a copy of the NEC. It's lots of fun to try
and figure out.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Jay Levitt

08-07-2003, 02:26 PM

In article <bgtugp$21l$1@panix2.panix.com>, kludge@panix.com says...
> Jay Levitt <jay+news@jay.fm> wrote:
> >
> >The ground itself is a thick braided cable, 3/0 gauge if I'm reading the
> >smudged printing correctly. Oddly, I only see this cable going to one
> >of the two panels, and one is NOT a sub-panel of the other; perhaps the
> >ground is tied between them with regular Romex? These are 200-amp
> >panels, FWIW.
>
> The code says that each individual service needs to be grounded, so that
> second panel should have a connection to a ground. Pull the cover off
> and look inside and see if it doesn't.

I actually need to pull the cover off to take photos for Cutler-Hammer
anyway. I presume that this is the sort of operation I'd want to shut
the main power off to do...? I worry about the (metal) panel brushing
against live wires, etc. as I remove it.

> >The other bad part is that the ground cable runs at LEAST 30 feet before
> >disappearing into a crawlspace. That doesn't seem like a good thing. I
> >suspect that this ground wire was not redone when the house was rewired,
> >so it could be as old as 1970, when the house was first wired (it used
> >to be a carriage house). Heck, it could be going nowhere at all
> >anymore.
>
> The code says this is okay, as long as "the ground electrode is as near
> as practicable to and preferably in the same area as the grounding conductor
> connection to the system" (250-26C).

I figured it was OK for code, but presumably bad for lightning
discharge, yes?

> >Interestingly, nothing in my studio seems to have been damaged. I
> >assumed that was because of the Equitech isolation panel, but perhaps
> >it's actually because the studio has its own ground rod, which is much
> >more likely to be done correctly. That's all behind drywall, so I can't
> >see where it goes.
>
> The isolation systems provide some isolation from trash on the power
> lines, but they don't do anything about polluted grounds.

Is that true even for the balanced power systems?

> Does the studio have a seperate service? If so, it should have an individual
> ground.

Nope, it doesn't - the Equitech panel is run off a 70A breaker on a
nearby sub-panel. However, the design for the studio specified a
separate, way-the-hell-oversized ground for audio reasons.

> Go to the bookstore and get a copy of the NEC. It's lots of fun to try
> and figure out.

I'd rather get a hundred thousand paper cuts on my face...

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

Scott Dorsey

08-07-2003, 04:07 PM

Jay Levitt <jay+news@jay.fm> wrote:
>
>I actually need to pull the cover off to take photos for Cutler-Hammer
>anyway. I presume that this is the sort of operation I'd want to shut
>the main power off to do...? I worry about the (metal) panel brushing
>against live wires, etc. as I remove it.

You probably should. I've never done it, and I'm still okay, though.
(In fact, my house doesn't have a main shutoff... the cartridge fuses
at the top of the panel are always live. I keep saying I'll upgrade
the panel but frankly the old panel is fine and it's grandfathered in
under the old code).

Just don't touch anything live.

>> >The other bad part is that the ground cable runs at LEAST 30 feet before
>> >disappearing into a crawlspace. That doesn't seem like a good thing. I
>> >suspect that this ground wire was not redone when the house was rewired,
>> >so it could be as old as 1970, when the house was first wired (it used
>> >to be a carriage house). Heck, it could be going nowhere at all
>> >anymore.
>>
>> The code says this is okay, as long as "the ground electrode is as near
>> as practicable to and preferably in the same area as the grounding conductor
>> connection to the system" (250-26C).
>
>I figured it was OK for code, but presumably bad for lightning
>discharge, yes?

Right, you want as short and straight a connection as possible. In many
installations, the main service entry point (which may or may not be the
main panel) is located in a place specifically so it can have a good
ground.

>> >Interestingly, nothing in my studio seems to have been damaged. I
>> >assumed that was because of the Equitech isolation panel, but perhaps
>> >it's actually because the studio has its own ground rod, which is much
>> >more likely to be done correctly. That's all behind drywall, so I can't
>> >see where it goes.
>>
>> The isolation systems provide some isolation from trash on the power
>> lines, but they don't do anything about polluted grounds.
>
>Is that true even for the balanced power systems?

Yes. The balanced power buys you nothing over isolation, other than reduced
chassis leakage. This can be a big deal with old guitar amps but most of
the time it's no advantage. These things are much more marketing than
substance, but they DO provide a good low-pass and good isolation on the
line.

>> Does the studio have a seperate service? If so, it should have an individual
>> ground.
>
>Nope, it doesn't - the Equitech panel is run off a 70A breaker on a
>nearby sub-panel. However, the design for the studio specified a
>separate, way-the-hell-oversized ground for audio reasons.

Wait, so the subpanel is grounded seperately? With additional lightning
arrestors at the subpanel?

>> Go to the bookstore and get a copy of the NEC. It's lots of fun to try
>> and figure out.
>
>I'd rather get a hundred thousand paper cuts on my face...

No, really, it's like a huge puzzle where they give you only the answers
and you try to figure the questions out. Think of it as a game!
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

w_tom

08-07-2003, 04:09 PM

Thirty feet to earth ground is fine for human safety
requirements that concern code. But code does not establish
requirements for transistor safety - surge protection. Thirty
feet would be low resistance - sufficient earthing for code.
But thirty feet would be high impedance - insufficient
earthing for surge protection.

Earthing for surge protection usually means both meeting and
exceeding what code required. That connection to earth ground
must be less than 10 feet, no splices, no sharp bends, not
bundled with other wires, etc.

Furthermore, any other utility that enters that same "other
service" area must first be earthed to the same ground.
Others call it ground bounce or earth borne surges. But an
area with multiple earth grounds means damage from surge
transients is possible - again a failure directly traceable to
human failure. If cable or ethernet network wire or whatever
does not connect to that same '10 foot distant' earth ground
before entering that area, then surge damage such (as those
from earth) is possible.

Again, none of this is addressed by code because code only
addresses human safety issues. Owner is concerned with human
safety and electronic safety meaning that owner earth in
excess of what code requires - especially if the facility has
separate AC mains service and therefore separate single point
grounds.

Scott Dorsey wrote:
> ...
> The code says that each individual service needs to be grounded, so
> that second panel should have a connection to a ground. Pull the
> cover off and look inside and see if it doesn't.
>
> It might be done with insulated wire, if the installing electrician
> had some lying around, but that is not necessary or useful and
> costs more.
>
>> The other bad part is that the ground cable runs at LEAST 30
>> feet before disappearing into a crawlspace. That doesn't seem
>> like a good thing. I suspect that this ground wire was not
>> redone when the house was rewired, so it could be as old as
>> 1970, when the house was first wired (it used to be a carriage
>> house). Heck, it could be going nowhere at all anymore.
>
> The code says this is okay, as long as "the ground electrode is
> as near as practicable to and preferably in the same area as the
> grounding conductor connection to the system" (250-26C).
> ...

Jay Levitt

08-07-2003, 10:24 PM

>
> >> Does the studio have a seperate service? If so, it should have an individual
> >> ground.
> >
> >Nope, it doesn't - the Equitech panel is run off a 70A breaker on a
> >nearby sub-panel. However, the design for the studio specified a
> >separate, way-the-hell-oversized ground for audio reasons.
>
> Wait, so the subpanel is grounded seperately? With additional lightning
> arrestors at the subpanel?

According to the plans, there should be a separate 4-gauge ground cable
running from the Equitech to the main ground rod. I seem to recall the
electrician telling me he just sunk a separate ground rod to keep the
run short. There are no separate lightning arrestors on the Equitech,
but it is downstream of the main panel which has them...

----------------- ---------------- ----------------
| 200A Panel A |-----|100A sub-panel|---|Equitech panel|
-|w/suppressor|-- ---------------- ----------------
| |
| really long ground braid | ground #2
V V

-----------------
| 200A Panel B |
-|w/suppressor|--
|
|
V

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

Roger W. Norman

08-08-2003, 07:00 AM

Just put the A/C on the other rail and the light problem should go away,
BUT, don't do it if your room is going to be on the same rail. In fact,
plan with your electrician to put all the noisy motor stuff, A/C,
Freezers/refrigerators, humidifiers, sump pumps, etc., either on one rail or
run a sub-panel that handles those pieces of equipment.

The problems with most grids is that the most current draw is in the newer
sections where houses typically have 200 amp services and actually USE them,
plus a lot of housing tracts are surrounded by industrialized areas. I
upgraded our box to 200 amps and absolutely use it, but that's because I'm
in an old section of town (75 year old house) that has no air ducts to run
central air and heat. When I was doing the design for adding the woodshop
and the pool heater/filter, I found only ONE circuit running that was
drawing more than 10 amps (the pool filter and some stuff). Everything else
was pretty much pulling maybe 2 amps, but I didn't check when all the A/C
units were fired up.

The point being that all the older housing was designed with maybe 60 amp
panels, a few light circuits, MAYBE an electric range and MAYBE an electric
clothes dryer, but not much more than that. So the grid in the old sections
of town usually represents THAT design rather than the design of today where
someone may do Arc welding for a hobby, or have 4 computers running along
with at least one TV all day. Then there's the microwave, a toaster oven,
A/C, you name it. The grid's ability to put the electricity over it is
fine, but it's the inability of the grid to handle large system draws, which
is why I was lucky enough to be living in an area where my friend was
responsible for doing the grid redesign. Once his design was implemented,
most of my apparent problems went away. Not saying I don't have a small
ground loop here or there, but they are defeatable if I wish to take a
couple of minutes. But to prove the point, about two years after I was
basking in my luck of great electrical supply, Pepco came over and swapped
out my old analog meter for a new digitally probed unit (honesly why can't
they just use FTP?) which wasn't seated quite right and I raised a stink
about it. After some hemming and hawing, they finally came over, yanked out
the new meter and simply seated it better and I've been back to nice clean
power ever since.

Your problem doesn't seem likely to go away just from some of your efforts.
This sounds like you're going to need to get the power company involved to
sort the problems out. And they aren't likely to want to accomodate you if
it means they have to put out lots of money to redesign and implement their
grids.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Jay Levitt" <jay+news@jay.fm> wrote in message
news:MPG.199b4716641401b09899ef@news-east.giganews.com...
> In article <bgr09i$rta$1@bob.news.rcn.net>, rnorman@starpower.net
> says...
> > There are arc triggered breakers that see a "serious" drain on a system,
> > like a unit frying, and do their job of breaking. Simple replacements
for
> > the panel, and although I think it would work for outside events, it's
> > principally designed to stop arc from dangerous internal circuits. I
don't
> > know what it would do if it saw too much current coming in.
>
> If these are what I'm thinking of, they are actually now required for
> bedrooms as of 2002 or 2003. The electrician and I discussed installing
> them in 2001 when we renovated, but at that point he felt they were
> somewhat new, tripped way too easily, and that I shouldn't be a guinea
> pig - better to wait for the second generation of equipment once
> everyone else started installing these things en masse.
>
> > Plus, were you home when this happened? Do you know how close the
strike
> > was? Even some of our household equipment and computers and such are
> > effected by strikes that can set off a local micro "EMP" burst from 70
> > million volts coming close. This would certainly bypass any electronics
> > used to monitor/condition/interrupt the power as it's a physical
phenomena
> > not reduced to using wires.
>
> I wasn't home. I didn't see any trees down near me. In fact, as
> thunderstorms go, this seemed pretty tame. When I lived in Northern
> Virginia, the forecast every day from May to October was "hot, hazy,
> humid, chance of thundershowers", and we had some doozies, yet I never
> lost a single piece of equipment. In New England we get maybe a dozen
> storms a season, and here I have things frying left and right... that
> was one reason I called the power company. I figured maybe they had
> received multiple reports from customers, but no.
>
> > So I'd suggest that you find someone at the power company who will
> > come over and take a look at what you're running, give him any
documentation
> > of what's been happening, and I'll bet somebody will get the grid right.
>
> Not a bad idea at all, once I straighten out the questionable grounding.
> Wellesley has its own tiny power company, and I've talked to their
> engineer on a few occasions for other reasons (most recently to figure
> out why my lights were dimming on a 400-amp service when a 150A-LRA air
> conditioner kicks in. Never did figure that out, but now I'm on my own
> personal transformer secondary...)
>
> --
> Jay Levitt |
> Wellesley, MA | Hi!
> Faster: jay at jay dot eff-em | Where are we going?
> http://www.jay.fm | Why am I in this handbasket?

Roger W. Norman

08-08-2003, 07:04 AM

Interestingly enough, most of the storms seem to come right down the Potomac
river, and generally stay on the low side of DC (Virginia side), but when I
do get hit, it's likely to make the house move. Living at one of the
highest places around, it's always bothered me somewhat, but my fears have
been only that so far. Still, enough come through to cause problems, and I
still proactively shut down the studio and the computers when my dog shows
up in the studio under my desk. That means he knows something I don't, so
it's time to batten down the hatches! <g> He hears storms that are out near
Leesburg, which is a good 35 miles from here.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Mike Rivers" <mrivers@d-and-d.com> wrote in message
news:znr1060216687k@trad...
>
> In article <MPG.199b4716641401b09899ef@news-east.giganews.com>
jay+news@jay.fm writes:
>
> > When I lived in Northern
> > Virginia, the forecast every day from May to October was "hot, hazy,
> > humid, chance of thundershowers", and we had some doozies, yet I never
> > lost a single piece of equipment.
>
> That's where I am, that's what the forecast is, and that's what we
> get. I lost a gutter once, but that was because a tree fell on it.
>
>
>
> --
> I'm really Mike Rivers - (mrivers@d-and-d.com)

Roger W. Norman

08-08-2003, 07:14 AM

And that's why I am taking the electrical and re-doing it, which, of course,
puts the patio thing on a slower track because I have to carefully dig up
all that 6/2 UFB cable and re-do the circuits without touching the shell of
the pool. Admittedly, a non conducting mouting surface, outdoor
weatherproofed boxes, GFI breakered power and a properly run 8' #6 ground
rod should do the job, but not the way NEC states the job should be done.

Looks like I won't get this yard done until we're into the fall, dammit. Oh
well, maybe we'll get a couple of bushels of crabs and have a crab feast
instead. Who the hell wants to party in the heat of August with a pool and
A/C going in the studio? <g>

Of course, if you want to stop by and help on one of your weekends up here,
I'll be glad to provide all the comforts like meals, beers, a swim in the
pool, bathtub spa (if you need it). Know anything about doing brick mason
work or even how to mix mortar to the right consistency? <g>

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Scott Dorsey" <kludge@panix.com> wrote in message
news:bgr6dm$ngk$1@panix2.panix.com...
> Roger W. Norman <rnorman@starpower.net> wrote:
> >
> >Now I'm a kinda hands on guy, so when I saw this I called my Pepco friend
> >back over, and I've since redone the electrical to meet code even if an
> >inspector isn't coming over. But in some cases, maybe an inspector is
the
> >best way to get the local utility to do it's job. If not, prepare to
learn
> >something about electricity and then make some design changes. The
concept
> >of a field wide grounding system isn't that big of a deal. It takes less
> >time than the damage that can ensue costs.
>
> A lot of electricians just plain don't know the code outside the little
> area where they normally work. The code is big and it's pretty dense,
> and it can be difficult to read because it explains what to do but never
> why it's necessary.
>
> If he's never looked at the swimming pool section of the code, he might
> very well not know that this is a bad thing to do.
>
> I know that I have had a lot of nightmares dealing with licensed
electricians
> at festival gigs and film shoots who have never used remote generators and
> don't know about the varied and unusual grounding regulations for remote
power
> systems. (Regulations that do make sense if you sit down and really think
> about them, but which can seem alarming if you don't. I had a lot of fun
> explaining to one fellow at the Potomac festival last year that his
generator
> had to run ungrounded and that tying it to a ground rod was a code
violation,
> but that if it was connected to a fixed trailer it would have to be
grounded).
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

Roger W. Norman

08-08-2003, 07:24 AM

A subpanel is not necessary to ground separately, but a new SERVICE needs to
be grounded separately. A subpanel runs off a circuit from the panel using
whatever breaker/wire combination necessary to handle the amperage. But in
Jay's case, if BOTH are 200 Amp circuits, well, there's no breaker big
enough to do that job except in a new service panel, so probably Jay DOES
need the second panel to be grounded to it's own ground point. It cannot be
grounded to the original service's grounding point or tied back into that
braid.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Scott Dorsey" <kludge@panix.com> wrote in message
news:bgtugp$21l$1@panix2.panix.com...
> Jay Levitt <jay+news@jay.fm> wrote:
> >
> >The ground itself is a thick braided cable, 3/0 gauge if I'm reading the
> >smudged printing correctly. Oddly, I only see this cable going to one
> >of the two panels, and one is NOT a sub-panel of the other; perhaps the
> >ground is tied between them with regular Romex? These are 200-amp
> >panels, FWIW.
>
> The code says that each individual service needs to be grounded, so that
> second panel should have a connection to a ground. Pull the cover off
> and look inside and see if it doesn't.
>
> It might be done with insulated wire, if the installing electrician had
> some lying around, but that is not necessary or useful and costs more.
>
> >The other bad part is that the ground cable runs at LEAST 30 feet before
> >disappearing into a crawlspace. That doesn't seem like a good thing. I
> >suspect that this ground wire was not redone when the house was rewired,
> >so it could be as old as 1970, when the house was first wired (it used
> >to be a carriage house). Heck, it could be going nowhere at all
> >anymore.
>
> The code says this is okay, as long as "the ground electrode is as near
> as practicable to and preferably in the same area as the grounding
conductor
> connection to the system" (250-26C).
>
> >Interestingly, nothing in my studio seems to have been damaged. I
> >assumed that was because of the Equitech isolation panel, but perhaps
> >it's actually because the studio has its own ground rod, which is much
> >more likely to be done correctly. That's all behind drywall, so I can't
> >see where it goes.
>
> The isolation systems provide some isolation from trash on the power
> lines, but they don't do anything about polluted grounds.
>
> Does the studio have a seperate service? If so, it should have an
individual
> ground.
>
> >My electrician's had a family emergency, but when he gets back to work,
> >maybe he can shed some (battery-powered) light on the grounding system
> >here.
>
> Go to the bookstore and get a copy of the NEC. It's lots of fun to try
> and figure out.
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

Roger W. Norman

08-08-2003, 07:26 AM

You don't ground a subpanel unless you are effectively making it another
service. Technically, what I did (run a 60 amp circuit to the woodshop
subpanel with a grounding rod) causes that to be another service, but code
wise there should be another run of electrical from the street to that panel
to create a new service. So not having the grounding braid from both panels
is incorrect in your situation.

Most likely your grounding braid simply ties to a grounding rod in the crawl
space. Of course, you can always pull on the damned thing and see if it's
hooked up to anything. But you seriously need to have your electrician look
at the grounding and get it fixed, if what you report is correct.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Jay Levitt" <jay+news@jay.fm> wrote in message
news:MPG.199b43f7987efb409899ed@news-east.giganews.com...
> In article <bgq0c0$lt0$1@panix2.panix.com>, kludge@panix.com says...
> > Ground impedance at very high frequencies is a big issue, which is why
> > the ground wire has to go from the panel straight to the rod without
> > any loops or kinks along the way. Lightning is a very fast risetime
> > pulse, so you need to think about stuff in the MHz region and not just
> > DC.
>
> Interesting and educational.. thanks. I realized that code is only a
> minimum standard, but hadn't thought about the vast difference in
> requirements between a safety ground and a lightning discharge.
>
> The ground from my panel is not via the water pipe, although (as
> mentioned elsewhere in the thread it's bonded to that, and in fact any
> gaps in that (e.g. water filter, softener) have large jumpers.
>
> The ground itself is a thick braided cable, 3/0 gauge if I'm reading the
> smudged printing correctly. Oddly, I only see this cable going to one
> of the two panels, and one is NOT a sub-panel of the other; perhaps the
> ground is tied between them with regular Romex? These are 200-amp
> panels, FWIW.
>
> The other bad part is that the ground cable runs at LEAST 30 feet before
> disappearing into a crawlspace. That doesn't seem like a good thing. I
> suspect that this ground wire was not redone when the house was rewired,
> so it could be as old as 1970, when the house was first wired (it used
> to be a carriage house). Heck, it could be going nowhere at all
> anymore.
>
> Interestingly, nothing in my studio seems to have been damaged. I
> assumed that was because of the Equitech isolation panel, but perhaps
> it's actually because the studio has its own ground rod, which is much
> more likely to be done correctly. That's all behind drywall, so I can't
> see where it goes.
>
> My electrician's had a family emergency, but when he gets back to work,
> maybe he can shed some (battery-powered) light on the grounding system
> here.
>
> --
> Jay Levitt |
> Wellesley, MA | Hi!
> Faster: jay at jay dot eff-em | Where are we going?
> http://www.jay.fm | Why am I in this handbasket?

Roger W. Norman

08-08-2003, 07:29 AM

Don't be a wimp. Two screws and you'd really have to **** up to "brush" any
wires. Electricians install my previously run circuits all the time without
bringing the house down. However, if you like resetting all your clocks
again...! <g> And besides, one can never be too safe around electricity,
especially service panels. I regularly open mine because I'm always running
new circuits, but regularly may mean once a year.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Jay Levitt" <jay+news@jay.fm> wrote in message
news:MPG.199c7ff27108c41c9899f1@news-east.giganews.com...
> In article <bgtugp$21l$1@panix2.panix.com>, kludge@panix.com says...
> > Jay Levitt <jay+news@jay.fm> wrote:
> > >
> > >The ground itself is a thick braided cable, 3/0 gauge if I'm reading
the
> > >smudged printing correctly. Oddly, I only see this cable going to one
> > >of the two panels, and one is NOT a sub-panel of the other; perhaps the
> > >ground is tied between them with regular Romex? These are 200-amp
> > >panels, FWIW.
> >
> > The code says that each individual service needs to be grounded, so that
> > second panel should have a connection to a ground. Pull the cover off
> > and look inside and see if it doesn't.
>
> I actually need to pull the cover off to take photos for Cutler-Hammer
> anyway. I presume that this is the sort of operation I'd want to shut
> the main power off to do...? I worry about the (metal) panel brushing
> against live wires, etc. as I remove it.
>
> > >The other bad part is that the ground cable runs at LEAST 30 feet
before
> > >disappearing into a crawlspace. That doesn't seem like a good thing.
I
> > >suspect that this ground wire was not redone when the house was
rewired,
> > >so it could be as old as 1970, when the house was first wired (it used
> > >to be a carriage house). Heck, it could be going nowhere at all
> > >anymore.
> >
> > The code says this is okay, as long as "the ground electrode is as near
> > as practicable to and preferably in the same area as the grounding
conductor
> > connection to the system" (250-26C).
>
> I figured it was OK for code, but presumably bad for lightning
> discharge, yes?
>
> > >Interestingly, nothing in my studio seems to have been damaged. I
> > >assumed that was because of the Equitech isolation panel, but perhaps
> > >it's actually because the studio has its own ground rod, which is much
> > >more likely to be done correctly. That's all behind drywall, so I
can't
> > >see where it goes.
> >
> > The isolation systems provide some isolation from trash on the power
> > lines, but they don't do anything about polluted grounds.
>
> Is that true even for the balanced power systems?
>
> > Does the studio have a seperate service? If so, it should have an
individual
> > ground.
>
> Nope, it doesn't - the Equitech panel is run off a 70A breaker on a
> nearby sub-panel. However, the design for the studio specified a
> separate, way-the-hell-oversized ground for audio reasons.
>
>
> > Go to the bookstore and get a copy of the NEC. It's lots of fun to try
> > and figure out.
>
> I'd rather get a hundred thousand paper cuts on my face...
>
> --
> Jay Levitt |
> Wellesley, MA | Hi!
> Faster: jay at jay dot eff-em | Where are we going?
> http://www.jay.fm | Why am I in this handbasket?

Roger W. Norman

08-08-2003, 07:34 AM

A subpanel SHOULD NOT be running to a separate ground. The ground runs back
from the subpanel to the service or it's a real, separate service. A new
service needs grounding. A subpanel should not be grounded. 70 Amps
requires 6/2 cable for anything less than 150 feet, so your Equitech panel
is indeed a new service and needs to have it's own ground. If it doesn't
have 6/2 cable or larger, then it's the wrong wire, and it's wired wrong.

Damn, you have a mishmash of electrical in your house.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Jay Levitt" <jay+news@jay.fm> wrote in message
news:MPG.199c7ff27108c41c9899f1@news-east.giganews.com...
> In article <bgtugp$21l$1@panix2.panix.com>, kludge@panix.com says...
> > Jay Levitt <jay+news@jay.fm> wrote:
> > >
> > >The ground itself is a thick braided cable, 3/0 gauge if I'm reading
the
> > >smudged printing correctly. Oddly, I only see this cable going to one
> > >of the two panels, and one is NOT a sub-panel of the other; perhaps the
> > >ground is tied between them with regular Romex? These are 200-amp
> > >panels, FWIW.
> >
> > The code says that each individual service needs to be grounded, so that
> > second panel should have a connection to a ground. Pull the cover off
> > and look inside and see if it doesn't.
>
> I actually need to pull the cover off to take photos for Cutler-Hammer
> anyway. I presume that this is the sort of operation I'd want to shut
> the main power off to do...? I worry about the (metal) panel brushing
> against live wires, etc. as I remove it.
>
> > >The other bad part is that the ground cable runs at LEAST 30 feet
before
> > >disappearing into a crawlspace. That doesn't seem like a good thing.
I
> > >suspect that this ground wire was not redone when the house was
rewired,
> > >so it could be as old as 1970, when the house was first wired (it used
> > >to be a carriage house). Heck, it could be going nowhere at all
> > >anymore.
> >
> > The code says this is okay, as long as "the ground electrode is as near
> > as practicable to and preferably in the same area as the grounding
conductor
> > connection to the system" (250-26C).
>
> I figured it was OK for code, but presumably bad for lightning
> discharge, yes?
>
> > >Interestingly, nothing in my studio seems to have been damaged. I
> > >assumed that was because of the Equitech isolation panel, but perhaps
> > >it's actually because the studio has its own ground rod, which is much
> > >more likely to be done correctly. That's all behind drywall, so I
can't
> > >see where it goes.
> >
> > The isolation systems provide some isolation from trash on the power
> > lines, but they don't do anything about polluted grounds.
>
> Is that true even for the balanced power systems?
>
> > Does the studio have a seperate service? If so, it should have an
individual
> > ground.
>
> Nope, it doesn't - the Equitech panel is run off a 70A breaker on a
> nearby sub-panel. However, the design for the studio specified a
> separate, way-the-hell-oversized ground for audio reasons.
>
>
> > Go to the bookstore and get a copy of the NEC. It's lots of fun to try
> > and figure out.
>
> I'd rather get a hundred thousand paper cuts on my face...
>
> --
> Jay Levitt |
> Wellesley, MA | Hi!
> Faster: jay at jay dot eff-em | Where are we going?
> http://www.jay.fm | Why am I in this handbasket?

Roger W. Norman

08-08-2003, 07:38 AM

Then run two rods, tying those together with some #3 braid, and ground to
one. Gives the effective grounding of an 8' rod in a 4 foot depth. The
bigger the rod, the better! <g>

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"ScotFraser" <scotfraser@aol.com> wrote in message
news:20030806164743.00947.00000078@mb-m11.aol.com...
> << You can get air powered
> palm nailers that will take a #6 8' copper rod and put it 7' 11" into the
> ground in about 15 seconds. I think that's the thing that scares most
> people from doing their own grounding work. Trying to drive the rod in.
> Short work with the right tools. >>
>
> Not where I live. There's solid rock about 4 feet down. Both studio ground
rods
> I've installed over the years just stopped right there & the biggest
sledges in
> the hands of the strongest guys on site just couldn't get it any further,
while
> completely mushrooming the top. So that's where we cut it off.
>
>
> Scott Fraser

Roger W. Norman

08-08-2003, 07:38 AM

No common ground points for boxes, please. The new service (the Equitech)
should have it's own ground point, so he did the right thing.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Jay Levitt" <jay+news@jay.fm> wrote in message
news:MPG.199cf01c783c0d1c9899f2@news-east.giganews.com...
> >
> > >> Does the studio have a seperate service? If so, it should have an
individual
> > >> ground.
> > >
> > >Nope, it doesn't - the Equitech panel is run off a 70A breaker on a
> > >nearby sub-panel. However, the design for the studio specified a
> > >separate, way-the-hell-oversized ground for audio reasons.
> >
> > Wait, so the subpanel is grounded seperately? With additional lightning
> > arrestors at the subpanel?
>
> According to the plans, there should be a separate 4-gauge ground cable
> running from the Equitech to the main ground rod. I seem to recall the
> electrician telling me he just sunk a separate ground rod to keep the
> run short. There are no separate lightning arrestors on the Equitech,
> but it is downstream of the main panel which has them...
>
> ----------------- ---------------- ----------------
> | 200A Panel A |-----|100A sub-panel|---|Equitech panel|
> -|w/suppressor|-- ---------------- ----------------
> | |
> | really long ground braid | ground #2
> V V
>
> -----------------
> | 200A Panel B |
> -|w/suppressor|--
> |
> |
> V
>
> --
> Jay Levitt |
> Wellesley, MA | Hi!
> Faster: jay at jay dot eff-em | Where are we going?
> http://www.jay.fm | Why am I in this handbasket?

Dave Martin

08-08-2003, 09:15 AM

"Roger W. Norman" <rnorman@starpower.net> wrote to Scott Dorsey>

Know anything about doing brick mason
> work or even how to mix mortar to the right consistency? <g>
>
Somehow, I'm afraid that he does...

--
Dave Martin
Java Jive Studio
Nashville, TN
www.javajivestudio.com

Jay Levitt

08-08-2003, 12:04 PM

In article <bh08f7$kv2$1@bob.news.rcn.net>, rnorman@starpower.net
says...
> A subpanel SHOULD NOT be running to a separate ground. The ground runs back
> from the subpanel to the service or it's a real, separate service. A new
> service needs grounding. A subpanel should not be grounded. 70 Amps
> requires 6/2 cable for anything less than 150 feet, so your Equitech panel
> is indeed a new service and needs to have it's own ground.

I'm confused. I thought a "new service" means that it's actually a
parallel feed from the street - e.g. right now I have two 200-amp
services going to two main panels (with two big shutoffs outside). But
the Equitech is hanging off a 70A breaker in a subpanel, as depicted in
my stunningly aesthetic diagram elsewhere in this thread.. am I
misunderstanding what a service is, or is the whole thing just wired
wrong?

I am starting to wonder if maybe I shouldn't wait for this electrician
to get back to work, but should instead call someone else, and get a
second pair of eyes on it...

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

Scott Dorsey

08-08-2003, 01:37 PM

Jay Levitt <jay+news@jay.fm> wrote:
>In article <bh08f7$kv2$1@bob.news.rcn.net>, rnorman@starpower.net
>says...
>> A subpanel SHOULD NOT be running to a separate ground. The ground runs back
>> from the subpanel to the service or it's a real, separate service. A new
>> service needs grounding. A subpanel should not be grounded. 70 Amps
>> requires 6/2 cable for anything less than 150 feet, so your Equitech panel
>> is indeed a new service and needs to have it's own ground.
>
>I'm confused. I thought a "new service" means that it's actually a
>parallel feed from the street - e.g. right now I have two 200-amp
>services going to two main panels (with two big shutoffs outside).

Right.

>But
>the Equitech is hanging off a 70A breaker in a subpanel, as depicted in
>my stunningly aesthetic diagram elsewhere in this thread.. am I
>misunderstanding what a service is, or is the whole thing just wired
>wrong?

The Equitech isolates the input and output lines, SO the neutral wire on
the input has no connection to the neutral wire on the output.

This means that the ground on the input doesn't need to be connected to
the ground on the output either, and you can have a seperate ground for
the circuits on the other side of the isolation transformer, and lift the
ground on the line from the main service panel to the isolation transformer.

This is the big deal about isolation transformers, that you are now totally
separated from the grounding system in the rest of the building. So everything
on the secondary is like having a different service altogether.

>I am starting to wonder if maybe I shouldn't wait for this electrician
>to get back to work, but should instead call someone else, and get a
>second pair of eyes on it...

If I were you, I'd call a lightning protection company. Find out who your
local Staticat dealer is and talk to them.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Jay Levitt

08-08-2003, 02:55 PM

In article <bh0u56$5g4$1@panix2.panix.com>, kludge@panix.com says...
> The Equitech isolates the input and output lines, SO the neutral wire on
> the input has no connection to the neutral wire on the output.

Right.. and in fact the neutral isn't even neutral anymore, being
balanced power. (If you get electrocuted by a negative voltage, does it
make you more alive?)

> This means that the ground on the input doesn't need to be connected to
> the ground on the output either, and you can have a seperate ground for
> the circuits on the other side of the isolation transformer, and lift the
> ground on the line from the main service panel to the isolation transformer.

AH! Because, as I always forget, the neutral and ground are actually
(normally) tied together, so you can't cascade the neutral but have a
separate ground. I think I see now.

I'm so glad I went into software. I still don't quite follow how all
the little minus signs get over to the big plus sign...

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

Dale Farmer

08-08-2003, 11:27 PM

"Roger W. Norman" wrote:

> And that's why I am taking the electrical and re-doing it, which, of course,
> puts the patio thing on a slower track because I have to carefully dig up
> all that 6/2 UFB cable and re-do the circuits without touching the shell of
> the pool. Admittedly, a non conducting mouting surface, outdoor
> weatherproofed boxes, GFI breakered power and a properly run 8' #6 ground
> rod should do the job, but not the way NEC states the job should be done.
>
> Looks like I won't get this yard done until we're into the fall, dammit. Oh
> well, maybe we'll get a couple of bushels of crabs and have a crab feast
> instead. Who the hell wants to party in the heat of August with a pool and
> A/C going in the studio? <g>
>
> Of course, if you want to stop by and help on one of your weekends up here,
> I'll be glad to provide all the comforts like meals, beers, a swim in the
> pool, bathtub spa (if you need it). Know anything about doing brick mason
> work or even how to mix mortar to the right consistency? <g>

room temperature peanut butter. Leave no voids in the mortar. When your
mortar starts to get stiff, toss it and mix a fresh batch. Don't work too
fast
for the mortar. If you go too fast the still wet mortar below gets squeezed out

by the weight of the bricks above and the whole structure starts to tilt. Take
your time, check your level *every* course of bricks. Don't forget to tie the
face bricks to the inner layers of the wall/chimney. Use bricks that are outdoor

rated for outdoor structures. Make your foundation stronger than you think
it needs to be. Much stronger, the Building Code is the minimum, not the
best.
( I was a masons helper when I was a teenager, on the houses that my
grandfather built... as well as carpenter's helper, electricians helper,
cleanup
guy and go get lunch guy. One of the happiest day of my younger life was
when my granddad finally broke down and bought a power saw. )

Dale Farmer

08-08-2003, 11:30 PM

Scott Dorsey wrote:

> Jay Levitt <jay+news@jay.fm> wrote:
> >In article <bh08f7$kv2$1@bob.news.rcn.net>, rnorman@starpower.net
> >says...
> >> A subpanel SHOULD NOT be running to a separate ground. The ground runs back
> >> from the subpanel to the service or it's a real, separate service. A new
> >> service needs grounding. A subpanel should not be grounded. 70 Amps
> >> requires 6/2 cable for anything less than 150 feet, so your Equitech panel
> >> is indeed a new service and needs to have it's own ground.
> >
> >I'm confused. I thought a "new service" means that it's actually a
> >parallel feed from the street - e.g. right now I have two 200-amp
> >services going to two main panels (with two big shutoffs outside).
>
> Right.
>
> >But
> >the Equitech is hanging off a 70A breaker in a subpanel, as depicted in
> >my stunningly aesthetic diagram elsewhere in this thread.. am I
> >misunderstanding what a service is, or is the whole thing just wired
> >wrong?
>
> The Equitech isolates the input and output lines, SO the neutral wire on
> the input has no connection to the neutral wire on the output.
>
> This means that the ground on the input doesn't need to be connected to
> the ground on the output either, and you can have a seperate ground for
> the circuits on the other side of the isolation transformer, and lift the
> ground on the line from the main service panel to the isolation transformer.
>
> This is the big deal about isolation transformers, that you are now totally
> separated from the grounding system in the rest of the building. So everything
> on the secondary is like having a different service altogether.
>
> >I am starting to wonder if maybe I shouldn't wait for this electrician
> >to get back to work, but should instead call someone else, and get a
> >second pair of eyes on it...
>
> If I were you, I'd call a lightning protection company. Find out who your
> local Staticat dealer is and talk to them.
> --scott

You are getting into 'Separately derived service' I think the phrase is.
It is touched on in a couple of the NEC chapters. Go and read some more.

--Dale

Dale Farmer

08-08-2003, 11:36 PM

"Roger W. Norman" wrote:

> You don't ground a subpanel unless you are effectively making it another
> service. Technically, what I did (run a 60 amp circuit to the woodshop
> subpanel with a grounding rod) causes that to be another service, but code
> wise there should be another run of electrical from the street to that panel
> to create a new service. So not having the grounding braid from both panels
> is incorrect in your situation.
>
> Most likely your grounding braid simply ties to a grounding rod in the crawl
> space. Of course, you can always pull on the damned thing and see if it's
> hooked up to anything. But you seriously need to have your electrician look
> at the grounding and get it fixed, if what you report is correct.
>
> --
>
> Roger W. Norman
> SirMusic Studio
> Roger@SirMusicStudio.com
> 301-585-4681

If you have two service entrance panels in the building, and their ground
rods
are not close to each other, then you probably have some voltage present between

the two ground references. I've personally see 30 volts difference in a hotel
ballroom, where the stage power came from one end onf the building, and the
wall plugs up on the balcony came from another end of the building. I've heard
tell of larger differences.
So if your PC in your bedroom is on the house panel, and the signal cable
to the mixer in the studio plugged into the other panel, may be causing a huge
ground loop on that signal wire. This is speculation, of course.

--Dale

Roger W. Norman

08-09-2003, 05:31 AM

Ah, somewhat akin to me being pleased that, as a plumber's helper, we
finally got a power threader for gas pipe. Spent a year on gas piping
alone.

Good tips on the mason stuff, but I've been working alone, so there's really
no time to let mortar sit. I make it, go get the next corse of blocks, mud
it and do it again. Luckily it's just a retaining wall, so if it leaned,
and did so in the direction of the higher level of dirt, that wouldn't be
too bad. But so far so good. I'll be doing the facing with brick and can
start that pretty soon. Then it's truckloads of dirt and gravel, make about
80 more concrete pavers (that's the one that hurts the back), one 60 lbs bag
per mould, wait an hour, do it again (and I have four moulds). I still have
3,000 lbs of concrete to move up out of the driveway - by myself. What's
the use in having kids?

BTW, I check level on every block. Although I don't trust NOT doing so, so
far each corse has been correct.

--

Roger W. Norman
SirMusic Studio
Roger@SirMusicStudio.com
301-585-4681

"Dale Farmer" <Dale@cybercom.net> wrote in message
news:3F34863D.341BE938@cybercom.net...
>
>
> "Roger W. Norman" wrote:
>
> > And that's why I am taking the electrical and re-doing it, which, of
course,
> > puts the patio thing on a slower track because I have to carefully dig
up
> > all that 6/2 UFB cable and re-do the circuits without touching the shell
of
> > the pool. Admittedly, a non conducting mouting surface, outdoor
> > weatherproofed boxes, GFI breakered power and a properly run 8' #6
ground
> > rod should do the job, but not the way NEC states the job should be
done.
> >
> > Looks like I won't get this yard done until we're into the fall, dammit.
Oh
> > well, maybe we'll get a couple of bushels of crabs and have a crab feast
> > instead. Who the hell wants to party in the heat of August with a pool
and
> > A/C going in the studio? <g>
> >
> > Of course, if you want to stop by and help on one of your weekends up
here,
> > I'll be glad to provide all the comforts like meals, beers, a swim in
the
> > pool, bathtub spa (if you need it). Know anything about doing brick
mason
> > work or even how to mix mortar to the right consistency? <g>
>
> room temperature peanut butter. Leave no voids in the mortar. When
your
> mortar starts to get stiff, toss it and mix a fresh batch. Don't work
too
> fast
> for the mortar. If you go too fast the still wet mortar below gets
squeezed out
>
> by the weight of the bricks above and the whole structure starts to tilt.
Take
> your time, check your level *every* course of bricks. Don't forget to tie
the
> face bricks to the inner layers of the wall/chimney. Use bricks that are
outdoor
>
> rated for outdoor structures. Make your foundation stronger than you
think
> it needs to be. Much stronger, the Building Code is the minimum, not the
> best.
> ( I was a masons helper when I was a teenager, on the houses that my
> grandfather built... as well as carpenter's helper, electricians helper,
> cleanup
> guy and go get lunch guy. One of the happiest day of my younger life was
> when my granddad finally broke down and bought a power saw. )
>

Bruce L. Bergman

08-20-2003, 08:31 AM

On Wed, 6 Aug 2003 09:44:19 -0400, someone who calls themselves "Roger
W. Norman" <rnorman@starpower.net> wrote:

>There are arc triggered breakers that see a "serious" drain on a system,
>like a unit frying, and do their job of breaking. Simple replacements for
>the panel, and although I think it would work for outside events, it's
>principally designed to stop arc from dangerous internal circuits. I don't
>know what it would do if it saw too much current coming in.
>

I know I'm late on this (this newsgroup is like getting a drink out
of a firehose), but an Arc Fault circuit breaker won't work for
lightning strikes.

The AFCI is looking for arc effects on the Load side that you would
get from a Romex staple pinch inside the wall (possibly causing a
smouldering fire inside the wall) or a bad appliance cord to trip the
breaker - a few thousand volts coming in the Line side from a
lightning strike will just fry the whole thing....

--<< Bruce >>--
--
Bruce L. Bergman, POB 394, Woodland Hills CA 91365, USA
Electrician, Westend Electric (#726700) Agoura, CA

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