residential service entrance grounding

[-=PEAKABOO=-]

We have not done houses in a year or 2 and the last time we did there was copper water pipe. Now the houses we are going to be doing are using red and blue pex pipe and black plastic pipe to the water meter. The slabs have no steel and only use post tension cables. How are you guys grounding the service?

 

[hotwire1955]

Ground rod #6 copper #4 alum. two rods if 25 ohms or less

 

[augie47]

Building Codes here require most to have rebar in the footers so that solves that problem.
Like you, we see few metallic water lines so those without CEE get ground rods.

 

[-=PEAKABOO=-]

We usually have a ground rod and also a cold water clamp. There is rebar in the slab except for a few short pieces. The beams have post tension cables as well.

 

[infinity]

Ground rod #6 copper #4 alum. two rods if 25 ohms or less

The #4 Al is only good if it's more than 18" from the ground. Not much good unless you're using 10' rods.

 

[resistance]

Building Codes here require most to have rebar in the footers so that solves that problem.
Like you, we see few metallic water lines so those without CEE get ground rods.

I agree!!!!

 

[resistance]

We usually have a ground rod and also a cold water clamp. There is rebar in the slab except for a few short pieces. The beams have post tension cables as well.

Did you understand what augie said about the rebar?

 

[-=PEAKABOO=-]

Did you understand what augie said about the rebar?

Yes what I meant to say is there is NO rebar in the slab. except for a few pieces that are used as stakes to support the post tension cables. The beams all have post tension cables in them. I though this was strange but the slabs pass inspection. On top of this I may not have got the meaning of augies post. I am assuming you were referring to his CEE coment? No rebar and nothing else to ground to in the slab.

 

[infinity]

So no rebar and no metallic water pipe means that you have to install a made electrode. Pick one from the list in 250.53, (F), (G) or (H). The 8' ground rod(s) is the most common.

 

[hotwire1955]

So no rebar and no metallic water pipe means that you have to install a made electrode. Pick one from the list in 250.53, (F), (G) or (H). The 8' ground rod(s) is the most common.

or 10' rods if you use aluminum

 

[stjohnbarleycorn]

there is rebar in the footer, but it is not accessible, so a rod and #6, ground clamp for direct burial.

 

[RICK NAPIER]

If this is a new home the rebar in the footing if over 20' should have been used that is why in NJ they have the building inspectors look for this before footings are poured.

 

[Chamuit]

Lay or stake your ufer in the ground before the footing gets poured. Worry about bonding afterwards.

 

[infinity]

If this is a new home the rebar in the footing if over 20' should have been used that is why in NJ they have the building inspectors look for this before footings are poured.

One other requirement is that the rebar is #4 (1/2") or larger. I recently looked at an addition where the inspector failed the footing for not having a GEC connected to the 100' of rebar. The rebar was only #3 (3/8") but it failed anyway.

 

[LarryFine]

I recently looked at an addition where the inspector failed the footing for not having a GEC connected to the 100' of rebar. The rebar was only #3 (3/8") but it failed anyway.

What was the failure, and what was the correction (as the inspector saw it?)

 

[infinity]

What was the failure, and what was the correction (as the inspector saw it?)

The foundation guy called the architect who stated correctly that it wasn't required for 3/8" rebar. The inspector didn't care and said that it is required so no green sticker and no pour without the CEE. Concrete guy runs to Home Depot and buys a piece of #8 Cu solid and a clamp. Inspector returns and passes the footing. So the rebar is too small, the #8 is too small and the CEE is not required but the thing still gets a green sticker. Then as a parting shot he mentions that the electrical inspector will check to wire size when he inspects the service.

 

[LarryFine]

Outrageous. :roll:

 

[stjohnbarleycorn]

we are never there before the footer is poured, most of the time the footers are there before we bid on it.

 

[infinity]

we are never there before the footer is poured, most of the time the footers are there before we bid on it.

That still doesn't relieve someone of installing one. The key would be who is enforcing the code. Around here you won't get a green light to pour the footing without a footing inspection and possibly a CEE if required.