250.30 I am confusing myself

[dcspector]

I have a 4 pole ATS and a 3 pole ATS from same Generator. I missed the 3 pole first time around (Big Building) and had them bond at Generator. So my question is if both are from the Generator SDS did I mess up? How would one do the N-G bond with two separate ATS 4p and 3p or am I simply confusing myself as usual?

 

[wirenut1980]

If the ATS's get the alternate supply from the same generator, and the neutral is bonded at the generator, then both ATS's need to be 4 pole. Or they could remove the bond at the generator and make both ATS's 3 pole.

 

[dcspector]

If the ATS's get the alternate supply from the same generator, and the neutral is bonded at the generator, then both ATS's need to be 4 pole. Or they could remove the bond at the generator and make both ATS's 3 pole.

Thanks Wirenut. I actually knew that. However, I was confused as heck when I looked at the situation after miising the 3p. The EC is calling me back we think we have a designer issue. I will keep you posted.

 

[dcspector]

They are going to replace a 3p with a 4p. Just got off the phone. Coordination drawing issue.

 

[dcspector]

In summary what confused me for a bit was all trusted the EE on the plans.

 

[zbang]

This is why PEs have insurance for omissions & errors .

 

[dcspector]

This is why PEs have insurance for omissions & errors .

Exactly. I am upset with myself for not seeing that 3p ATS hidden and the EC forgot about it as well. (Big Building easy to get lost) Oh well all is taken care of. Thanks.

 

[erickench]

A 4P ATS would ensure that each system is separately derived. If this what you're trying to achieve then use the 4P. If not then use the 3P.