Mixing generator and general power in a common junction box

[mjc1060]

I am on a job where the generator and general power conduits feeding ATS share a common junction box. Does the NEC or NFPA have restrictions that prohibit this? Does anyone know where I can find more information on this.

 

[iwire]

Articles 700, 701 and 702 are where the NEC addresses this.


But you need to determine if this is really an emergency generator for things like egress lights, smoke evacuation etc. Or is it an optional standby by generator powering things the customer chooses to like data rooms, refrigeration equipment, machinery etc.

The rules change dependent on the use.

 

[mjc1060]

More than just emergency power

More than just emergency power

The generators (there are more than one) supply power for the whole building (all loads). There are also around 9 ATS in the mechanical rooms for chillers providing cooling for data rooms.

 

[Smart $]

The generators (there are more than one) supply power for the whole building (all loads). There are also around 9 ATS in the mechanical rooms for chillers providing cooling for data rooms.

Bob (iwire) pointed you in the right direction, but to narrow it down a bit, each emergency system must be kept separate from all non-emergency systems. See 700.2 for the definition and 700.10 for specifics.

Also, though you only mentioned junction boxes on the source side of the ATS's, wiring does have to enter and exit them. If any wiring is service conductors, then 230.7 prohibits other than service conductors from sharing the same raceway or cable.

 

[mjc1060]

Thank you

Thank you

Bob (iwire) pointed you in the right direction, but to narrow it down a bit, each emergency system must be kept separate from all non-emergency systems. See 700.2 for the definition and 700.10 for specifics.

Also, though you only mentioned junction boxes on the source side of the ATS's, wiring does have to enter and exit them. If any wiring is service conductors, then 230.7 prohibits other than service conductors from sharing the same raceway or cable.

There are no service conductors in the juntion boxes.
Thank you very much