grounding of service
- Thread starter boboelectric
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wireman3736
Senior Member
- Location
- Vermont/Mass.
gndrod said:3736, There may be two options if the plumber is using plastic or has the Water Heater in the garage. He's probably avoiding the copper cost crunch too. Let the GC run the UFER rebar if it's ok in your AHJ area. A six pack goes a long way.rbj, Seattle
I have two houses coming up in the next few weeks, the foundation guy's connected the ufer to the rebar and left a piece hanging out of the top of the foundation, I don't know if I feel comfortable about them doing this, You don't have to be licensed to do single family houses in Vermont and they don't have to be inspected, I couldn't get to either of these houses when they were doing the foundations. Who knows they could have just dropped the wire down in the wall before the pour.
Wow, that is a coin flip and no way of telling what is in there unless you are Clark Kent. See if the GC can answer that if you can trust him. If water pipe is being direct buried that is your best bet otherwise I'd back the GES up with rods to be NEC compliant. The UFER must be encased 2" around in concrete at the bottom of the footer in hard-pan per 250.52(A)(3). Also check the 6 AWG size min to match the service size you're going with. Ps. Some contractors skimp with 3/8 rebar (instead of the required 1/2" for a 200A UFER bonded with #4 AWG GEC.)
See if the GC can answer that if you can trust him. If water pipe is being direct buried that is your best bet otherwise I'd back the GES up with rods to be NEC compliant. The UFER must be encased 2" around in concrete at the bottom of the footer in hard-pan per 250.52(A)(3). Also check the 6 AWG size min to match the service size you're going with. Ps. Some contractors skimp with 3/8 rebar (instead of the required 1/2" for a 200A UFER bonded with #4 AWG GEC.)
- Location
- Massachusetts
LarryFine said:
Huh?
You can 'land' the GEC anywhere from the service point to the service disconnect
- Location
- Massachusetts
Roger that is clearly a serious violation.
It is imperative that the ground clamp be moved to the brass valve to provide an effective ground fault path.
Of course as it is it is about as effective as a ground rod.
It is imperative that the ground clamp be moved to the brass valve to provide an effective ground fault path.
Of course as it is it is about as effective as a ground rod.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
gndrod said:Wow, that is a coin flip and no way of telling what is in there unless you are Clark Kent.
If the contractor were to use 3/8" rebar a CEE is not required.
- Location
- Massachusetts
infinity said:
Good point.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
wireman3736 said:Who knows they could have just dropped the wire down in the wall before the pour.
And this would be unsafe in what way?
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Not unsafe, just not a 250.52-defined grounding electrode. You can pitch stuff down the formers all day and not hurt anybody.petersonra said:
- Location
- Massachusetts
georgestolz said:
I agree.
What if 'stuff' includes an apprentice or two?
Hi Trevor, Ideally a six pack to get the GC to put in the 1/2" Ufer for you will save the cost of buying and pounding 2 ground rods, bonding jumper, one acorn, one junior weaver, and extra length GEC costly copper. I must have milsled you to think you didn't need to bond to an undersized 3/8" rebar Ufer. My intent being keep an eye what is being installed for the project. The electrical trade takes clever backscratching to save bucks and a six pack is a great trade for a free UFER in the footer stubbed up under the Service Main. BTW, using 3/8" or #3 rebar in footers is a UBC or IRC violation for most stemwall installations. This is my opinion and intended to help future money conscious EC's. rbj, Seattle
rbj, Seattle
- Location
- New Jersey
- Occupation
- Journeyman Electrician
gndrod said:Hi Trevor, Ideally a six pack to get the GC to put in the 1/2" Ufer for you will save the cost of buying and pounding 2 ground rods, bonding jumper, one acorn, one junior weaver, and extra length GEC costly copper. I must have milsled you to think you didn't need to bond to an undersized 3/8" rebar Ufer. My intent being keep an eye what is being installed for the project. The electrical trade takes clever backscratching to save bucks and a six pack is a great trade for a free UFER in the footer stubbed up under the Service Main. BTW, using 3/8" or #3 rebar in footers is a UBC or IRC violation for most stemwall installations. This is my opinion and intended to help future money conscious EC's.
I agree that using a CEE is easier and possibly better than pounding in two ground rods. The point is, if the rebar is 1/2" or larger than a CEE is required. If it's 3/8" than the CEE is not required. You could always make your own by laying 20" of bare copper at the base of the footing. This would easier and cheaper than using 2 ground rods. The 3/8" rebar makes the CEE optional, 1/2" or larger does not.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Easier if scheduling is easy.infinity said:
Cheaper if gas for that first trip is cheap.
If you've got a crew that can wrap a house in a day's roughing, that extra trip may not be cheaper or easier. Just throwing that out there.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
georgestolz said:Easier if scheduling is easy.
Cheaper if gas for that first trip is cheap.
If you've got a crew that can wrap a house in a day's roughing, that extra trip may not be cheaper or easier. Just throwing that out there.
You're right. My assumption was based on you being there at the time of the footing be setup. Some of the time this isn't going to happen so a separate trip wouldn't be cost effective. We try to install the temporary service at the same time the footing is ready for the CEE connection to make only one trip.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
That is so simple it's positively brilliant. I wish I had thought of it first! Thanks, Trevor.infinity said:
Ok, Most homes are lower end laterals that are surface mounted. If you ever get to do a recessed configuration, the sweep must be roughed in the forms. That just about requires you to be there to lay in a #4 rebar or the required copper electrode conductor also. (And in CA the high-end developers almost always require a recessed setup.) I repeat, 3/8 rebar is a UBC code violation in the foundation footer and retainers so expect #4 every time. rbj, Seattle.
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winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
georgestolz said:
My guess: When you have multiple grounding electrodes, you can _expect_ current to flow from one to the other, caused by any current flowing through the earth. This current flow may be caused by systems that have multiple grounds (eg. multi-earth-neutral primary distribution), systems that intentionally use the earth as a conductor (eg. single wire earth return distribution) or natural effects (lightning). If you connect a GEC between some ground rods and the main disconnect, and a second GEC from the water pipe electrode and a subpanel, then this current would flow on the EGC between the two panels.
Real problem? I don't know. Is this any different from having a _supplemntary_ ground rod at a piece of equipment where the rod is connected to the EGC?
-Jon
A/A Fuel GTX
Senior Member
- Location
- WI & AZ
- Occupation
- Electrician
The way I read 250.52 (A) (3), the CEE would still be required by virtue of the " or " in between the 1/2" rod requirement and the 20' of bare #4 option. If the building has footings, the ability to install a CEE would be there and I would take the word " present " from 250.50 as the enforceable kicker.infinity said:
- Location
- New Jersey
- Occupation
- Journeyman Electrician
m73214 said:
I disagree. If the building is surrounded by earth is a ground rod required? A CEE that isn't 1/2" or larger rebar is a made electrode. Absence of the 1/2" or larger rebar removes the requirement to use the footing. It becomes optional. The code allow me to use whatever made electrode that I choose to supplement the water pipe. If I choose I could use 20' of Cu in the footing but it is not required.
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