GEC

[tshea]

After looking at Mike Holt's diagrams and reading the NEC, I believe that I can route the GEC from the service panel, in a concrete slab then up to the copper water line entering the building. GEC will be #4. Service size is 100A, resi 120/240v. Water line from street is copper pipe. I also need to jumper the water meter, and protect the #4 when it exits the concrete slab by the panel and water meter. Length is approx 40'.

Do you agree?

 

[jwelectric]

Re: GEC

If you want me to agree I will.

 

[bphgravity]

Re: GEC

Sounds good to me too. What part are you questioning?

 

[JohnE]

Re: GEC

Originally posted by bphgravity:
Sounds good to me too. What part are you questioning?

I too agree that you can do that. But, per table 310.15(B)(6) you are only required to use #2 Aluminum or #4 copper service entrance conductors and per table 250.66 only requied to use #8 copper GEC.

Oops, meant to reply to original post, not Bryan's reply.

[ December 01, 2005, 11:18 AM: Message edited by: j_erickson ]

 

[tshea]

Re: GEC

Originally posted by j_erickson:
and per table 250.66 only requied to use #8 copper GEC.

I'm using the #4 as a concrete encased electrode, therefore it must be #4.

Sounds good to me too. What part are you questioning?

Just bouncing this off the experts!

 

[physis]

Re: GEC

I like to use 4 just because it doesn't need to be protected everywhere.

 

[paul32]

Re: GEC

Originally posted by tshea:

Originally posted by j_erickson:
and per table 250.66 only requied to use #8 copper GEC.

I'm using the #4 as a concrete encased electrode, therefore it must be #4.

250.66(B) indicates you don't need to go larger than 4AWG (if table 250.66 indicated 2AWG, the connection to the concrete encased electrode could still be 4AWG). So you can use 8AWG, but since 250.64(B) requires it in a raceway or cable armor, I would use a 6AWG.

 

[JohnE]

Re: GEC

Originally posted by tshea:

Originally posted by j_erickson:
and per table 250.66 only requied to use #8 copper GEC.

I'm using the #4 as a concrete encased electrode, therefore it must be #4.

Sounds good to me too. What part are you questioning?

Just bouncing this off the experts!

A concrete encased electrode must be at or near the bottom of a foundation or footing. Running the #4 through or under the poured floor to the water pipe is ok, it just will not be considered an electrode. So, you will have to supplement the water pipe if there isn't any additional electrode available.

 

[George Stolz]

Re: GEC

John, he just needs to be sure that 20' of the #4 is in the proper location. After that he can encase hula hoop shapes at the top of the foundation wall if he is so inclined.

Sounds like a great method, if he's confident on where the water pipe will be with certainty.

 

[JohnE]

Re: GEC

It is a good method. I do it regularly. I was not exactly sure of what the question was , so I was trying to just cover all aspects of the install.

 

[mc5w]

Re: GEC

Back when John Labriola was an electrical contractor he would go into a house before the basement slab was poured, drive a ground rod well below the basement floor, run the GEC unbroken from the panel location straight down to the ground rod, under the slab and over to the water meter.

You also need to consider 250.64(B) mechanical strength requirements which can be interpreted to require a #4 copper GEC to a ground rod. Akron, Ohio and a few other places require a minimum of #4 solid copper or #2 stranded copper because they do not want to fool around with checking for a GEC that is closely following the woodwork.

Actually though, the minimum service that I would put into a single family dwelling would be 200 amps. 100 amp services tend to spot weld the service entrance conductors to the circuit breaker and meter terminals!

 

[tshea]

Re: GEC

Originally posted by mc5w:
Actually though, the minimum service that I would put into a single family dwelling would be 200 amps. 100 amp services tend to spot weld the service entrance conductors to the circuit breaker and meter terminals!

In this case the house is under 800 sqft. Gas stove, gas water heater, gas furnace, gas dryer. Laundry, sump pump, microwave.
This is a Habitat for Humanity new house. Since the work I do on it is FREE, as no charge, I'm looking for the MOST COST EFFECTIVE way to do certain parts of the job. Square D supplies the QO main breaker panel for free also.

 

[roger]

Re: GEC

mc5w,

Originally posted by mc5w:
100 amp services tend to spot weld the service entrance conductors to the circuit breaker and meter terminals!

have you been sniffing silicone again? :roll:

Roger