Relocating ATS

[jeff owens]

we are relocating an ATS installing it 30 feet from the existing location. due to limited space we are removing the switch and utilizing the existing enclosure to extend the sources to the new location as a junction box.. the conductors will be terminated on insulated blocks and/or extended to the new ATS enclosure. because the conduit penetrations are impossible to move (imbedded in concrete, chased to existing equipment etc.), we are simply making additional penetrations in the existing box. engineers are quoting article 700.10 (B) and interpreting it to say the conductors cannot be mixed in the same enclosure. are they not already? this box will remain strictly for the emergency system. they are requiring us to separate one set that is only feeding through. we are talking 500McM conductors, not easily formed or enclosed in sealtight. what is the intent of the code? Can 700.10 (b) (5) be applied here?? it is making our life very difficult.

 

[charlie b]

this box will remain strictly for the emergency system.

Unfortunately, I believe this statement is not true. The loads served by this box (this ?used-to-be-an-ATS-and-is-now-a-junction-box? box) are all emergency loads. But the box will have both normal source conductors and emergency source conductors coming in to it. That is the problem.

engineers are quoting article 700.10 (B) and interpreting it to say the conductors cannot be mixed in the same enclosure. are they not already?

They are. But that is acceptable because the box is presently an ATS. Having normal and emergency source conductors entering the same ATS is allowed by 700.10(B)(1). Once you convert the ATS to a junction box, that article will no longer apply. You will need to keep the normal source conductors separated from the emergency source conductors. I think you might be able to achieve this by installing some type of metal wall to separate the two sets of wires.

Can 700.10 (b) (5) be applied here??

No, that paragraph will not help you. It only talks about the conductors from the emergency power source. You are dealing with wires from both the normal source and the emergency source.

what is the intent of the code?

The intent is to prevent a fire or other fault that takes place within the normal source conductors from being able to damage the emergency source conductors.

 

[steve66]

So you are installing a new ATS, and in the old ATS you are leaving the normal power wiring and the generator power wiring? And maybe even the load side wiring?

In general, if this is an article 700 system, that would not be allowed. Wiring from the emergency source and normal source are allowed to be in the same ATS (they almost have to be), but they are not allowed to share other enclosures or splice boxes, or conduits. What was an ATS is no longer an ATS, so the normal and emergency wiring can't both be in the same box.

 

[jeff owens]

source commercial power will be relocated to the new ATS from the MDS. only the generator feeds and the redundant UPS/Battery back-up will be in the Junction box.