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Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom
reply to SmokChsr

Re: Surge Protection Residential Whole House

said by SmokChsr:

said by Jack_in_VA:

You have to know Wayne in spite of what you think, say or write your opinions mean nothing except to you. The inspector is the only one who matters and if he says to do something do it.

Until he leaves, then do it right.
If you read the NEC, (not something I do very often) you'll see for a fact that the inspector is WRONG! That leaves the question, are you going to do a proper job or just make the inspector happy at the cost of lost equipment, and dangerous conditions?

quote:
250.53(B) Electrode Spacing. Where more than one of the electrodes of the type specified in 250.52(A)(5) or (A)(7) are used, each electrode of one grounding system (including that used for air terminals) shall not be less than 1.83 m (6 ft) from any other electrode of another grounding system. Two or more grounding electrodes that are bonded together shall be considered a single grounding electrode system."

Given the two ground rods are bonded together with #6 solid copper wire it is considered a single grounding electrode system. That single system can't be less than 6 ft from another system.


49528867
Premium
join:2010-04-16
Fort Lauderdale, FL
kudos:3
reply to Jack_in_VA

said by Jack_in_VA:

It blew up most of the glass tube spark gap enclosures the telco had on their incoming circuits. They spent a lot of time repairing/replacing them and getting our phone system back up.

That’s old school, protectors used nowadays are hybrids providing gas tubes for the primary protection, backed by MOV for through thru protection and solid state protection facing the CPE.

Wayne
--
Madness takes its toll, please have exact change ready…


49528867
Premium
join:2010-04-16
Fort Lauderdale, FL
kudos:3
reply to Jack_in_VA

said by Jack_in_VA:

Given the two ground rods are bonded together with #6 solid copper wire it is considered a single grounding electrode system. That single system can't be less than 6 ft from another system.

Incorrect.

250.56 Resistance of Rod, Pipe, and Plate Electrodes.
A single electrode consisting of a rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional electrode of any of the types specified by 250.52(A)(2) through (A)(7). Where multiple rod, pipe, or plate electrodes are installed to meet the requirements of this section, they shall not be less than 1.8 m (6 ft) apart.

Note.
Where multiple rod, pipe, or plate electrodes are installed to meet the requirements of this section, they shall not be less than 1.8 m (6 ft) apart.

In the code "shall not means something."

Wayne
--
Madness takes its toll, please have exact change ready…


Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom
reply to CajunWon

OP I found some good equipment for lightning and surge protection. I don't think a single device will cover everything that needs protection effectively.

Lightning & Surge Protective Devices


laserfan

join:2005-01-14
Texas
reply to 49528867

said by 49528867:

If you cannot go down you might be able to trench horizontally (below the frost line if applicable) and achieve the same results by laying a bare conductor in the trench if you are limited in the length of you trench you can add a product before backfilling such as Erico GEM to enhance your grounds effectiveness.

»www.erico.com/products/GEM.asp

Now there is something I've never seen (nor heard of) before! Can't imagine we can get it from our local HD/Lowes though!

Or maybe we can--the local HD does have very-large-sheets of copper w/ground connection for this very purpose. Pricey as heck of course.


Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom

2 edits

said by laserfan:

said by 49528867:

If you cannot go down you might be able to trench horizontally (below the frost line if applicable) and achieve the same results by laying a bare conductor in the trench if you are limited in the length of you trench you can add a product before backfilling such as Erico GEM to enhance your grounds effectiveness.

»www.erico.com/products/GEM.asp

Now there is something I've never seen (nor heard of) before! Can't imagine we can get it from our local HD/Lowes though!

Or maybe we can--the local HD does have very-large-sheets of copper w/ground connection for this very purpose. Pricey as heck of course.

Ground Plate - An electrode made to the requirements of NEC article 250-52 (d). The material used shall be a copper alloy intended for the purpose with a minimum thickness of 0.060”. Each plate shall expose a minimum of 5 ft2 of surface area to contact the soil. Grounding conductors shall be attached to the plate using a welding process. Splices made to the grounding conductor shall be made using a welding process. Dissimilar metals and solder connections shall not be allowed. Usually installed in a horizontal position.

Achieving an Acceptable Ground in Poor Soil-EC&M Article

Ground Rods and Touch Voltages

Ground rods are not enough to protect from lethal voltages.


49528867
Premium
join:2010-04-16
Fort Lauderdale, FL
kudos:3

In that article did you happen to catch this?

Always install multiple electrodes so they are more than 6 ft apart.

Wayne
--
Madness takes its toll, please have exact change ready…

laserfan

join:2005-01-14
Texas
reply to Jack_in_VA

Ok after reading all this stuff, and finding also this page on ground methods I am officially too smart for my own good.

The link says conventional ground rods suck, and even if I *was* able to somehow dig a 30" hole for a ground plate, it'd work poorly and last about a week.



This has been fun though. Maybe I'll play amateur chemist and build-my-own electrolytic...



Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom

said by laserfan:

Ok after reading all this stuff, and finding also this page on ground methods I am officially too smart for my own good.

The link says conventional ground rods suck, and even if I *was* able to somehow dig a 30" hole for a ground plate, it'd work poorly and last about a week.



This has been fun though. Maybe I'll play amateur chemist and build-my-own electrolytic...


It does show that there is way more considerations to effective grounding than many people realize. I especially liked finding an article on Touch Voltage. I had that in a seminar a long time ago.

You have rocks but Sandy soil is also a challenge but thankfully here I'm on the water and the water table is high enough for the ground rod to contact.

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
·callwithus
reply to laserfan

said by laserfan:

Ok after reading all this stuff, and finding also this page on ground methods I am officially too smart for my own good.

The link says conventional ground rods suck, and even if I *was* able to somehow dig a 30" hole for a ground plate, it'd work poorly and last about a week.



This has been fun though. Maybe I'll play amateur chemist and build-my-own electrolytic...


I suspect calcium chloride may be a good salt to use -- it's definitely a desiccant and would draw moisture from the atmosphere.

robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

1 recommendation

reply to laserfan

said by laserfan:

said by 49528867:

If you cannot go down you might be able to trench horizontally (below the frost line if applicable) and achieve the same results by laying a bare conductor in the trench if you are limited in the length of you trench you can add a product before backfilling such as Erico GEM to enhance your grounds effectiveness.

»www.erico.com/products/GEM.asp

Now there is something I've never seen (nor heard of) before! Can't imagine we can get it from our local HD/Lowes though!

Or maybe we can--the local HD does have very-large-sheets of copper w/ground connection for this very purpose. Pricey as heck of course.

I've used Erico GEM before. It's very interesting stuff. Seems like black tile grout with a lot of carbon (graphite) in it. I'm sure that's not how they make it, but that is what it seemed like. Very messy, stains your hands black, dries hard. I added extra ground rods to my system using it. Used a rock drill mounted on a Bobcat Excavator to drill 6" holes 8 foot deep and installed traditional ground rods in the bored holes using the GEM product. You could also use a rock saw to cut a trench. Best place to get Erico products in my area is Graybar. They do not stock GEM in Texas last I checked, but they do keep it in one of their warehouses somewhere up north. As I recall, the GEM product and shipping came to about $125 per hole (10 years ago).


49528867
Premium
join:2010-04-16
Fort Lauderdale, FL
kudos:3

said by robbin:

I've used Erico GEM before. It's very interesting stuff. Seems like black tile grout with a lot of carbon (graphite) in it.

Well consider this, Eirco builds Cadweld molds out of graphite so I am sure they have a silo or two of it on hand, then take that graphite powder and mix it with oh say some bentonite, add a touch of a chemical to lower ground resistance that will not attack copper or steel and meets the EPA leeching requirements, mix well and you have GEM.

And yes it is nasty to work with, I haven’t used GEM but have worked with a similar product sold by Harger.

»www.harger.com/

Wayne
--
Madness takes its toll, please have exact change ready…

robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

I don't think GEM has bentonite in It. It hardens (sets up firmly according to Erico) much like cement does. It doesn't loose conductivity when it dries. When I researched it years ago, it seemed that they had done something other than adding graphite to bentonite. The GEM performance seemed to indicate that they had taken a different path.


laserfan

join:2005-01-14
Texas
reply to robbin

said by robbin:

Used a rock drill mounted on a Bobcat Excavator to drill 6" holes 8 foot deep and installed traditional ground rods in the bored holes using the GEM product. You could also use a rock saw to cut a trench.

Ah yes, it seems in Texas a real man needs either a skid-steer or a backhoe. I'd love both but have only a lowly Tractor. I've used a little Dingo trencher (nice for laying low voltage wire) but not one of the big rock saws--our contractor broke one laying our main house conduit. Took 3 days continuous to get thru one ~35ft leg of the trench.

Anyway I like the Bobcat idea but it would be hard getting it close to where I need to put my rods. Still toying with making some sort of steel extension for use with a large masonry bit and my 1" hammer drill. Oughta be able to weld something that would work. Maybe I will just ask our rental guys about this.

robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

You can't drill a hole for a ground rod. They must be driven. The reason I went with GEM in a hole as opposed to a trench is than in summer the limestone dries out. I wanted to try to get contact with an area which may retain some moisture. The Bobcat was able to drill a 6" hole. Most everything and everyone else could only drill minimum of 9".



disconnected

@snet.net
reply to laserfan

Re: SPD

said by laserfan:

said by disconnected :

One thing often overlooked in the art of protecting against lightning on the mains drop is the fact that it is a high frequency event. The use of inductors to absorb the brunt of the energy, rather than simply trying to shunt 40,000 amperes to ground, is the route I chose in the 1960s. Historically, every summer, our neighbors complain of losing TVs, well pump motors and lights during electrical storms. In 46 years of living at this address, we have had zero problems with these lightning strikes to our branch, while the neighbors are replacing their electronic every summer. The difference is likely the loop of wire, coiled up before it comes into the service panel.

If you already said, I missed it: what does this "coiled-up loop of wire" in advance of the Service Panel look like? Can it be retrofitted into a site?

I completely buy the "high frequency event" statement. At least, an acquaintance of mine, along with having many things in his house fry, did also suffer major electrical damage to his truck with an indirect lightning strike.

As for the "single point ground", the way we are set-up this is really difficult to achieve as our pole and house and garage are 175, 200, and 150 feet apart from one another. We do have a swimming pool, with of course lots of in-ground rebar, and are grounded to *it*--I dunno but maybe this has helped (we've had lots of lightning in 9 years here but no damage to other than trees).

It looks like a coil, or a loop of wire. The size varies with the installation. One member here has a NEMA box with heavy guage wire coils in it, ahead of his panel. Mine's a coil about 4' diameter, and four turns. A neat installation could implement a large metal enclosure for the coil and mounted on a pedestal outside the residence.

Looking at lightning on a spectrum analyzer, one sees the whole baseline noise level jump about 30dB for distant lightning. It's easy to see how a local strike could be well over 100dB rise in voltage across the 1GHz spectrum.

For multiple buildings you might have them all tap a central earth ground nearest the center of the complex. Copper strapping, buried in concrete, is effective over moderate distances. Use of ordinary wire like Home Depot sells as "ground wire" is ineffective for anything more than static drainoff with a nearby strike. Heavy, and wide, copper strapping has an effectively low impedance at these higher frequencies. It's what we use at broadcast tower sites as ground and towers get hit several times a summer.

garys_2k
Premium
join:2004-05-07
Farmington, MI

I'd guess that the coils would need to be spread apart a bit to prevent flash-over from the incoming wires to those leaving for the house. Probably would be good to provide a low impedance arc path to ground in that enclosure, too.



SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL
reply to 49528867

Re: Surge Protection Residential Whole House

Eeeks!!! that's in Radio World!! Why would anyone want to write for a rag like that? theBDR.net is where all the good writers hangout


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL
reply to alkizmo

Click for full size
The right Chimney was struck
Click for full size
Off to the races..
said by alkizmo:

Ties everything together? You mean the multiple ground electrodes?
Or are you saying to ground anything that's conductive attached to the house, such as roof antenna, attic venting hoods, drain stacks and so on, to a #6 that goes to your ground rod?

It can be one or more ground electrodes, but they must all be bonded together outside.

Yes, I am saying anything conductive entering or attached to the structure should be bonded to the ground system. For an antenna mast, I would definitely want to home run it to the ground system. On the other roof items you have to use a judgement. While the best practice would be to bond everything, sometimes it's just not practical, especially in a residential setting. If you have an antenna mast it will tend to protect most other roof items in the area.

Case in point, I recently went to a $1mil+ house that burnt down after lightning struck the metal chimney cover, traveled down the flu pipe and arched over to the propane line. The arch caused a hole in the line and ignited the escaping propane. In this case it's very easy to see the lightning path from the chimney to the buried propane tank which was a very nice ground. There was a code violation that the propane line should have been bonded to the fireplace.


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL
reply to Jack_in_VA

said by Jack_in_VA:

Given the two ground rods are bonded together with #6 solid copper wire it is considered a single grounding electrode system. That single system can't be less than 6 ft from another system.

Close, but not exactly what it said. The rods of the single system can't be less than 6' apart, preferably they should be 8'-12' apart.
You had stated earlier that the inspector made you space them 5' apart, which didn't meet code. The primary reason the rods should be spaced is that if they are too close together the additional rod is not effective because it is trying to conduct into the same earth as the first rod. Or said another way, if the rods are too close together you wasted time and money driving the second rod, and it's not much more effective than a single rod.

Forget a second system, since you should NEVER have a second system at any one structure. As for the detached building, it likely doesn't need a rod of it's own, but as long as it was bonded by a #6 back to the house system, it is a part of that one system and should meet code.


49528867
Premium
join:2010-04-16
Fort Lauderdale, FL
kudos:3

said by SmokChsr:

Close, but not exactly what it said. The rods of the single system can't be less than 6' apart, preferably they should be 8'-12' apart. You had stated earlier that the inspector made you space them 5' apart, which didn't meet code.

250.56 Resistance of Rod, Pipe, and Plate Electrodes.
A single electrode consisting of a rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional electrode of any of the types specified by 250.52(A)(2) through (A)(7). Where multiple rod, pipe, or plate electrodes are installed to meet the requirements of this section, they shall not be less than 1.8 m (6 ft) apart.

When it comes to misinterpreting the code some AHJ’s are the best

Wayne
--
Madness takes its toll, please have exact change ready…

laserfan

join:2005-01-14
Texas
reply to robbin

said by robbin:

You can't drill a hole for a ground rod. They must be driven. The reason I went with GEM in a hole as opposed to a trench is than in summer the limestone dries out. I wanted to try to get contact with an area which may retain some moisture. The Bobcat was able to drill a 6" hole. Most everything and everyone else could only drill minimum of 9".

No doubt your point is: if you drill a hole thru solid rock you aren't going to get any grounding benefit. I was hoping for SOME grounding benefit in that the rock here is a mix of granite and caliche.

But it might be a whole lot of trouble for a very-little-or-no benefit so thanks for turning me off to drilling.

I guess I should rent the Bobcat and plant a rod w/GEM as close as I can get it, then couple to the building service with #6 or bigger.


49528867
Premium
join:2010-04-16
Fort Lauderdale, FL
kudos:3

said by laserfan:

I guess I should rent the Bobcat and plant a rod w/GEM as close as I can get it, then couple to the building service with #6 or bigger.

Do you plan to bond the sub buildings ground to the pole ground?

If so how are you going to get the wire from the sub building to the pole?

Wayne
--
Madness takes its toll, please have exact change ready…

laserfan

join:2005-01-14
Texas

Just a shallow trench.



49528867
Premium
join:2010-04-16
Fort Lauderdale, FL
kudos:3

said by laserfan:

Just a shallow trench.

Then drop a bare conductor in there and backfill it with some GEM and there's your ground for the sub building.

Wayne
--
Madness takes its toll, please have exact change ready…

laserfan

join:2005-01-14
Texas

Bare conductor...more GEM...hmm, that makes too much sense! Thanks!



SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL

I don't know about the costs, but there is also "conductive" concrete that is often poured in trenches to create a ground in rock. They use this mostly on mountain tops where it's solid rock. They say it's pretty darn good, though I've never had any experience with it myself. I'm a Florida boy, What's a rock??



49528867
Premium
join:2010-04-16
Fort Lauderdale, FL
kudos:3

said by SmokChsr:

I'm a Florida boy, What's a rock??

A rock is what you bruise your foot with when younger by steeping on and when older by dropping them.

Though as another Florida boy I must admit excepting the female form, everything else down here is flat as a pancake.

Wayne
--
Madness takes its toll, please have exact change ready…