Wire Size Chart With Grounding Conductor

[GaryBDavis]

I'm looking for a wire sizing chart that also has the minimum size conductor for the ground. I've searched my electical contractors book and it has all the wire sizing charts for voltage drop, etc but they don't include the ground size.

For example, a 200 amp service needs a 4AWG ground wire. I think 100 Amp is 8AWG. I'd like a chart that goes from 350 Amp service down to whatever size it is where the ground and hot/neutral are the same (I think its maybe 20 or 30 Amp).

If anyone has an online reference, please post the link for me.

Thanks!

 

[buckeyefarmer]

Table 250-95 of NEC

 

[Inspector507]

I think you're confusing 2 different NEC Tables. Table 250-66 sizes the Grounding Electrode Conductor that you would use for services which is different than Table 250-122 which sizes Equipment Grounding Conductors for Branch Circuits and Feeders.

BTW there is no Table 250-95 in the NEC.

 

[GaryBDavis]

I'm looking for both. I don't have a table that has the ground size for service entrance or branch circuits (if they are different).

I did find several on-line references to NEC table 250-95.

 

[Inspector507]

I did find several on-line references to NEC table 250-95.

Table 250-95 last appeared in the 1996 NEC. In 1999 all of Article 250 was reorganized. It was changed to 250-122.

 

[Inspector507]

This site has a calculator for both.

 

[GaryBDavis]

Cool site. Thanks!

 

[buckeyefarmer]

Table 250-95 last appeared in the 1996 NEC. In 1999 all of Article 250 was reorganized. It was changed to 250-122.

Thanks, 96 is last code book I bought.

 

[ahmed abdel rahman]

I have 38 KA,short circuit current .The earthing area is 40X80 meters,soil resistivity=420 ohm.meter.Iam asking about the most suitable earthing grid conductor size & the quantity& size of earthing rods?