grounding

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shaw0486

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If you have 2 transformers sitting side by side one of them is a 75 KVA and one is a 45 KVA and building steel is about 40' away can i run one grounding electrode to both of them. The 75 KVA requires a #2 and the 45 KVA requires a #8. So i was think could i use a #1 copper this equals the total circular mill of the #2 and the #8 added together?
 
well as long as it was kept continuous it would not make much differance but i could see the difficulty. But it would nt be a code issue?
 
It is permissible. Look at 250.30(A)(4) for some particular requirements.
If I read that section correctly, there is a requirement that the common electrode conductor be 3/0 minimum.
 
augie47 said:
It is permissible. Look at 250.30(A)(4) for some particular requirements.
If I read that section correctly, there is a requirement that the common electrode conductor be 3/0 minimum.
Click to expand...

Correct, 250.30(A)(4)(a) requires the common grounding electrode to be a 3/0 copper conductor.

The taps from the common GEC to each separately derived system can be sized based on the largest ungrounded secondary phase conductor of each transformer. (See 250.30(A)(4)(b))

Chris
 
augie47 said:
It is permissible. Look at 250.30(A)(4) for some particular requirements.
If I read that section correctly, there is a requirement that the common electrode conductor be 3/0 minimum.
Click to expand...


Over the years, there are so many changes. It took me making the mistake twice to finally remember this requirement. Good call Augi!

The OP can install the common Grounding Electrode Conductor, and tap off of it to supply each transformer, thus making maintenance on either not an issue in regards to the GEC.
 
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