shadyone72
New member
I need to ground multiple transformers to earth. Each unit requires a #2. How do I calculate the wire size needed to ground (4) of these units together?
Main GEC
- Thread starter shadyone72
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- Chapel Hill, NC
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- Retired Electrical Contractor
Are you asking about the gec to a ground rod ? Or do you mean EGC?
- Location
- Logan, Utah
Actually if you are connecting multiple separately derived systems to a single grounding electrode conductor the common grounding electrode must be a 3/0 and the taps to each transformer can be sized for each transformer.
Check out 250.30(A)(4) (2008 NEC)
Chris
It appears you are asking about sizing the GEC for multiple SDS's. If this is the case 250.30(A)(4) would be a good place to start. In this section it is permissible to use taps (sized based on the derived phase conductor) to a common GEC. The common GEC is required to be minimum 3/0 coper or 250kcmil AL.
Pete
Pete
- Location
- Logan, Utah
- Location
- Logan, Utah
You are correct Chris, I was posting before coffee.
Roger
Yep been there before.
I am not worth a whole lot until after my coffee kicks in.
Chris
Sparky340
New member
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- SACRAMENTO CA
Chris is correct on this I would look at 250.30 A 4
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