Size of GEC

[djtazjr]

What size GEC should be used with a 400 amp Residential service? 3/0 in parallel for the conductors.

 

[dana1028]

Re: Size of GEC

Where is the GEC terminating? water pipe, rod, Ufer, etc.?

 

[dereckbc]

Re: Size of GEC

Hint, 3/0 service conductor, 250.66.

 

[iwire]

Re: Size of GEC

Table 250.66 as Dereck pointed out.

Size of Largest Ungrounded Service-Entrance Conductor or Equivalent Area for Parallel Conductors (AWG/kcmil)

You said 2 sets of 3/0 you will need to go to Table 8 Conductor Properties to find the area of 3/0s and multiply that by 2 to find the equivalent area for your set up.

Once you have that you can use Table 250.66 to find the GEC size.

Take a look at 250.66(A), 250.66(B) and 250.66(C)
these articles may effect the size of the GEC.

Are these two sets of 3/0s in one raceway?

If yes, it is compliant with the use of 240.4(B) but you are pushing the limits, I hope the run is short.

 

[djtazjr]

Re: Size of GEC

It will be terminated on 8'x5/8" ground rods.

The conductors are in two seperate raceways for a total of 80 feet.

This is just another thing me and my super got into. I just dont know about him sometimes????

 

[iwire]

Re: Size of GEC

Originally posted by djtazjr:
It will be terminated on 8'x5/8" ground rods.

To the rods all you are required to use is 6 AWG regardless of the service conductor size.