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Old 02-22-2008, 01:45 PM   #1
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Ground Clamps Question


Im upgrading to 200 amp service and have a few questions.
First the clamps holding the riser show no more then 36" above the box it must be fastened (which right at the hight were the pipe runs threw the 2/4 header for the wall and out the roof). This is a flush mount panel so the 2" riser is running in the wall and taking up a good portion of with of the 2x4 wall. What kind of fastener can I use?
A u-clamp with screws on both sides wont fit due to the riser comming out of the box 1/2" from the side and not centered. I can fit those metal u-clamps that only have a hole on one side and use one screw/lag to hold it. It dont wrap all the way around the pipe just 50-60% around it. Would this work or is there special requirments for whats used to hold the riser pipe.
Heres a pic of the box.



Now onto my 2nd question. Im running 2 ground rods per requirements. They are more then 6' apart (around 8ft) and im running one to another then into the panel one contious wire. The wire I got is 4 guage stranded ground wire with a steel flex outside cover. (this is the same wire I ran from the water pipe infront of the house threw the crwal space under the house and into the panel on the back of the house. 80ft away)
My question is how do I fit the wire threw the clamp with the steel caseing on it. It has to be a contious wire and the ground clamps have a small hole on them for the wire that bearly fits as it is?
I plan on cementing the entire area where the groud rods are, which means the rods clamps and wire will all be under the slab when I finish. The clamps I have are rated for direct burial and they not only have a clamp for the wire but also a clamp for the wire caseing too.
Is the casing required? Can I leave the caseing on from the panel to the first clamp, then remove the caseing (which is going to be underground and under cement) from the first rod to the 2nd one?
Hows the inspector going to look at this. Theres a small 4-6" deep trench from one rod to the 2nd with a ground cable laying it (Then a few inchs away I drilled a hole threw the cement raised founadtion into the crawspace below the house then up into the wall and into the panel.
Does all seem ok? Thanks for your help JIM
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Old 02-22-2008, 03:01 PM   #2
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Ground Clamps Question


I have always used the Inspectors as an aid . . .a double check . . I dont know where you are at and thus which code is prevailent . .but I do not believe you can use " stranded " wire. Second . .It isnt my experience that the Inspectors care WHICH gadget we use to fasten the riser as long as it is
fastened well ands per interval your code requires

an excellent suggestion would be to work with your Inspector...PRIOR .to pouring concrete in anythig . .and have he and you agree on the correct set-up . . .you have an significant investment here . . . .lets not provide cause for failure . .or for having to dig it up

talk to your inspector and go over how you want to proceed


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Old 02-22-2008, 03:29 PM   #3
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Most inspectors would consider the pipe secured if it enters the top plate at or below the strapping requirement. In your case, if it enters the top plate at 36" and you need it supported there, you are OK.

As already mentioned by Kingsmurf, it will depend on your local codes, but the NEC allows a stranded grounding electrode conductor. If you put a grounding electrode conductor in a metal conduit, flexible or otherwise, the conduit must be bonded at both ends to the conductor. Usually this means using a connector that is designed for just that purpose. I know of no such connector that would allow you to install it in one continuous run and attach to each rod.

I would suggest as you mention, run it in the metal sheath to the first rod, then running it sheath-less to the next rod. I'm not sure if the metal sheath on the conductor is rated to be in direct contact with concrete.

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Last edited by InPhase277; 02-22-2008 at 03:33 PM.
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Old 02-22-2008, 03:58 PM   #4
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Thanks for the fast replys. Im not pouring any concrete for several months. The inspector will be out before then. So shall I be worried that the stranded wire I ran (took for ever under the crawspace) might not fly? I already installed 2 straps and the header is right at the max or maybe 1" over the max 36" rule so.
Maybe with the 2 straps I already installed and the header I should be ok. How do you fasten around the header besides sliding it threw the hole?

The cement shouldnt come in contact with the ground wire or sheath if I put dirt over the top then pour the cement correct?

Anything else I should worry about?
Anyone know whats the codes are on the stranded wire vs solid in the LA area of cali. The paper I have dont say. My local HD dont have larger sizes of ground wires in the sheath in sold wire. Smaller sizes they do. 6 or 4 is only stranded and it looked to be more used. So I choose that, but might have screwed up. Thanks again JIM
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Old 02-22-2008, 04:10 PM   #5
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Originally Posted by integlikewhoa View Post
Thanks for the fast replys. Im not pouring any concrete for several months. The inspector will be out before then. So shall I be worried that the stranded wire I ran (took for ever under the crawspace) might not fly? I already installed 2 straps and the header is right at the max or maybe 1" over the max 36" rule so.
Maybe with the 2 straps I already installed and the header I should be ok. How do you fasten around the header besides sliding it threw the hole?

The cement shouldnt come in contact with the ground wire or sheath if I put dirt over the top then pour the cement correct?

Anything else I should worry about?
Anyone know whats the codes are on the stranded wire vs solid in the LA area of cali. The paper I have dont say. My local HD dont have larger sizes of ground wires in the sheath in sold wire. Smaller sizes they do. 6 or 4 is only stranded and it looked to be more used. So I choose that, but might have screwed up. Thanks again JIM
I think you are OK as far as strapping goes. In general, but by no means a certainty, if you bought the material there it is most likely approved there.

Solid wires larger than #8 aren't allowed to be installed in conduit, so don't bother trying to find some. And what I mean about being in contact with concrete is for the metal of the sheath. You may be wise to install a short run of 1" PVC with an elbow from the top of the concrete to the first rod, and run your grounding flex in there. This will keep the concrete from actually touching the sheath before it enters. I say this because the concrete may have a corrosive effect on the cable and deteriorate the metal prematurely. Once it is below it, you are OK.

Now, you have your Earth ground. Do you have your cold water ground and gas pipe bonds? These are primo important. You also need to install jumpers around the water pressure regulator and meter. Assuming you have metal piping of course.

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Old 02-22-2008, 06:44 PM   #6
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Thanks for your info Inphase.

The 1st ground rod is only 6-8" away from the house, just enough to clear the footing. And there is a hole drilled below the cement level going threw the cement foundation under the house where the wire comes up threw the wall and into the box. So with dirt over the rod, wire and the hole, everything is below grade and therefore below cement. I think I should be good right? If not I got what your saying about some PVC pipe with the wire ran threw it.

So do you think the stranded wire is ok?

The water side I ran the same wire from outside the front of the house (no pressure reegulator at my house) hooked to the water line just before it enters the crawlspace. I then drilled a 1/2" hole in cement foundation and ran the wire threw under the house and down a large beam to the back of the house then up into the wall and into the box. The wire is held up to the beam by 1" electrical wire staples that are hammered in. The paper i had showed the wire needed to be connected with the first 4 foot of entering the house, and the inspector said hes not crawling under the house to inspect it so I better put it just outside of the house.

It paper they gave me when I pulled the permit didnt say anything about bonding the gas line. I have my meter in the vault out by the curb underground. Then ran under ground to the house where there is a riser a manual shut off valve, an automatic earthquake shutoff valve and then a 90 degree going under the house into the crawl space.

The old box had a ground going to the water line in the back of the house, which would have been a hell of alot easier for me. The box is on the back of the house and the water line is like 5 foot away.

Well im trying to head off any problems before the inspector comes out and makes me redo it all again. Thanks JIM
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Old 02-22-2008, 08:41 PM   #7
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Heres some more pictures. The 2 ground wires I have comming in does the metal caseing have to be removed where it enters the box?
Other then that how does everything else look?





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Old 02-22-2008, 08:42 PM   #8
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Secure some 2x4 backing above the top plate and thru bolt a 2 hole strap.


Thru bolting is REQUIRED here in AZ.


Your ground wire CAN'T be in steel flex (unless bonded which is a difficult manuver) It can be run bare or in PVC.


I have never been turned down for using stranded wire. It MAY be in a code (NEC/local?) somewhere.

Bond the water and gas in an accessible location.
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Old 02-22-2008, 09:05 PM   #9
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Originally Posted by integlikewhoa View Post


Now onto my 2nd question. Im running 2 ground rods per requirements. They are more then 6' apart (around 8ft) and im running one to another then into the panel one contious wire.

What's the requirement for 2 ground rods about. The only one I know about is the more than 25 ohms one, is that the one your talking about?
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Old 02-22-2008, 09:11 PM   #10
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Bonding to the gas line in my neck of the woods is considered to be sufficient by the use of the EGC run to a furnace or whatever else may be hooked into the gas sysem.
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Old 02-22-2008, 09:22 PM   #11
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Originally Posted by 220/221 View Post
Secure some 2x4 backing above the top plate and thru bolt a 2 hole strap.


Thru bolting is REQUIRED here in AZ.


Your ground wire CAN'T be in steel flex (unless bonded which is a difficult manuver) It can be run bare or in PVC.


I have never been turned down for using stranded wire. It MAY be in a code (NEC/local?) somewhere.

Bond the water and gas in an accessible location.
If I put a 2x4 behind the pipe above the top plate its going to stick out the wall. Thers only 1/2" between the pipe and the edge of the 2x4's (where the drywall mounts too) then you say threw bolt them so the bolts stick out even further? I woulds say this would work if the wall was was 6" thick, but after I put a 2" id pipe going threw a 3 1/2 (2x4) wall doesnt leave any room for a 2x4 turned up on its side and threw bolt it, plus the theres even less room on the side of the pipe to the 2x4 next to it. A bolt nor the strap would fit between the 2.

Should I pull all the flex off the wire? I bought a roll of 100ft of 4 guage. I used all of it.

I still havent read anything on bonding the gas and water together. Where can I read up on this?
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Old 02-22-2008, 09:27 PM   #12
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What's the requirement for 2 ground rods about. The only one I know about is the more than 25 ohms one, is that the one your talking about?
Its not code I from what I read, but when I pull the permit they gave me a paper which showed what they (local permit office) wanted. I have read about the ohm requirment, but I have also read online that unless you provide the equipment to prove that it is less then required, you should just throw that extra ground rod in. On top of that I put 2 10ft rods in. It shows 8ft min. like 30 bucks and my ground was soft. So no biggy. Rather be safe then to try and argue with the inspector when im no PRO. Thanks again JIM
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Old 02-22-2008, 09:36 PM   #13
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Requirements for water:

NEC 250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors. Interior metal water piping located more than 1.52 m (5 ft) from the point of entrance to the building shall not be used as a part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system.

Requirements for Gas:

NEC 250.104(B) Other Metal Piping. Where installed in or attached to a building or structure, a metal piping system(s), including gas piping, that is likely to become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with 250.122, using the rating of the circuit that is likely to energize the piping system(s). The equipment grounding conductor for the circuit that is likely to energize the piping shall be permitted to serve as the bonding means. The points of attachment of the bonding jumper(s) shall be accessible.

Now, why are you using 2 ground rods, greater than 25 ohms?
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Old 02-22-2008, 09:37 PM   #14
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Sorry, you responded faster than I can type. Local stuff, I understand thanks.
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Old 02-22-2008, 09:39 PM   #15
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Quote:
Originally Posted by integlikewhoa View Post
If I put a 2x4 behind the pipe above the top plate its going to stick out the wall. Thers only 1/2" between the pipe and the edge of the 2x4's (where the drywall mounts too) then you say threw bolt them so the bolts stick out even further? I woulds say this would work if the wall was was 6" thick, but after I put a 2" id pipe going threw a 3 1/2 (2x4) wall doesnt leave any room for a 2x4 turned up on its side and threw bolt it, plus the theres even less room on the side of the pipe to the 2x4 next to it. A bolt nor the strap would fit between the 2.

Should I pull all the flex off the wire? I bought a roll of 100ft of 4 guage. I used all of it.

I still havent read anything on bonding the gas and water together. Where can I read up on this?
No, do not pull the flex off the wire. If you have the clamps that are made to to secure the flex to as well as the wire, which you do, you can leave the flex.

As far as strapping goes, I think you are fine, because of the distance to the top plate. But, talk to your inspector anyway, he'll most likely understand.

As far as bonding the gas pipe, call the local inspections dept. They may or may not require you to bond it.

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