External bus bar to form grounding electrode system and size

[hhsting]

Can an external busbar be used to bond together grounding electrodes to form grounding electrode system? Please see attached. If yes then what size should the external bus bar be? 250.53(C) says binding jumper size to form grounding electrode system should be sized per table 250.66

 

[petersonra]

Iirc, it has to be a minimum of 1/4" thick by 2" wide. I don't recall that there is a minimum length specified.

 

[suemarkp]

250.64(C) says you can use a busbar to interconnect GEC's and 250.64(F)(1) also allows a busbar. The bar in that section says 1/4" thick by 2" wide and the length would be whatever you need to give enough space to terminate al the connections.

 

[hhsting]

Iirc, it has to be a minimum of 1/4" thick by 2" wide. I don't recall that there is a minimum length specified.

What exactly is bus bar thickness and width? So 0.25x2= 0.5 square inches.

So then how many square inches in 3/0awg? Is it in NEC 2017?

 

[LarryFine]

So then how many square inches in 3/0awg?

0.1318 sq. in.

 

[suemarkp]

The width is going to be whatever is wide enough to take the terminations. You have 4 conductors in the drawing. If you put a lug on each and bolt them to the bar side by side, you'd need at least a 4" bar and really I'd like at least a 6".

Table 5A in chapter 9 gives the area of conductors. 4/0 bare copper is .475 sq in.

 

[LarryFine]

Table 5A in chapter 9 gives the area of conductors. 4/0 bare copper is .475 sq in.

No, sorry, that's the diameter; the area is 0.219 sq. in. Look at Table 8.