Size of ground rods?

[djtazjr]

What size ground rod should be used and GEC with 400 amp residential service?

 

[iwire]

Re: Size of ground rods?

The rod could be as small as 1/2" x 8' and the GEC to this rod need not be larger than 6 awg regardless of service size.

 

[djtazjr]

Re: Size of ground rods?

Thanks Iwire, however, the service entrance will be 2-2" raceways containing 3/0 awg.

Then you size the GEC to the total area of the conductors correct?

 

[iwire]

Re: Size of ground rods?

As with many NEC questions it is not a yes or no answer.

If this GEC is running to the water pipe it will have to be sized as you say.

If the GEC is running just to a ground rod it will not be required to be larger than 6 awg copper.

If it was running to a concrete encased electrode it would not have to be larger than 4 awg.

250.66(A) Connections to Rod, Pipe, or Plate Electrodes. Where the grounding electrode conductor is connected to rod, pipe, or plate electrodes as permitted in 250.52(A)(5) or 250.52(A)(6), that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper wire or 4 AWG aluminum wire.

 

[djtazjr]

Re: Size of ground rods?

Thanks iwire! I really appreciate your help. Don't want to be argumentive; always appreciate help from the more experienced.

 

[iwire]

Re: Size of ground rods?

Originally posted by djtazjr:
Thanks iwire! I really appreciate your help. Don't want to be argumentative

Glad to help and I did not think you were being argumentative.

It is good to ask questions all it means is you care about your trade.

Personally I use a 2 awg bare to a rod.

In my opinion it stands up better over time and I usually have a cad weld mold that fits 2 awg to 3/4" rods in the truck.

 

[hurk27]

Re: Size of ground rods?

a cad weld mold that fits 2 awg to 3/4" rods in the truck.

Iwire how low is the resistance of the rod in your truck? LOL
Just had to ask.

 

[iwire]

Re: Size of ground rods?

Originally posted by hurk27:
Iwire how low is the resistance of the rod in your truck?

It depends if where I park the truck.

Puddle or dry sand.

 

[tonyi]

Re: Size of ground rods?

I always use the #2 and one-shots as well - one size fits all for most situations.