grounding conductor sizes

[uniondude]

I have a 400 amp 3 phase service being supplied with 4 500 mcm copper. All the grounds go directly from their grounding point to the main disconnect. There are 2 ground rods 6 ft. apart with #6 copper, a water line ground with #1/0 copper, a re-rod ground with #4 copper and a building steel ground with # 1/0 ground. Does this sound correct ?

 

[charlie b]

I'm no expert on ground wire sizes. But the 500 MCM does not sound right, unless you have a load calculation that shows a total load at or below 380 amps.

Welcome to the forum.

 

[augie47]

grounding electrode conductors sound correct also.
be sure service equipment is bonded

 

[Dennis Alwon]

I have a 400 amp 3 phase service being supplied with 4 500 mcm copper. All the grounds go directly from their grounding point to the main disconnect. There are 2 ground rods 6 ft. apart with #6 copper, a water line ground with #1/0 copper, a re-rod ground with #4 copper and a building steel ground with # 1/0 ground. Does this sound correct ?

It all sounds fine to me as long as you check what Charlie said in Post 2 about the 500 MCM copper. You don't need the ground rods.

 

[infinity]

You don't need the ground rods.

I agree. You could have looped the electrodes together instead of going back to a single point but everything else sounds like a normal 400 amp service.

 

[uniondude688]

It all sounds fine to me as long as you check what Charlie said in Post 2 about the 500 MCM copper. You don't need the ground rods.

You say you dont need the ground rods can you explain. They were required on the approved plans.

 

[tryinghard]

A compliant grounding system only requires [at leaste one of] an approved electrode as listed in 250.52, and of course all that are present shall be bonded together.

If your water pipe is an approved electrode it requires a supplimental with it, 250.53(D)(2). If the water pipe is not an approved electrode (does not meet all the criteria of 250.52(A)(1)) it still must be bonded (250.104) but supplimentals are not required.

 

[charlie b]

You say you dont need the ground rods can you explain. They were required on the approved plans.

"Required because the NEC says so" is different than "required because the plans say so," and both are different from "required because the inspector says so."

 

[augie47]

"Required because the NEC says so" is different than "required because the plans say so," and both are different from "required because the inspector says so."

we ALL know, ONLY THE LAST ONE COUNTS

 

[kstanton5]

Lightning Protection System Bond

Lightning Protection System Bond

Article 250.106 requires that the lightning protection system be bonded to the main grounding system. However no size requirements are given. Any suggestions?

 

[cparrott1984]

"Required because the NEC says so" is different than "required because the plans say so," and both are different from "required because the inspector says so."

HAHA, That's a catchy Saying!