This question might be better suited in the Building Codes area, but it also is NEC relavent.
Question is in regards to Emergency Egress Lighting (Fluorescent fixtures, not Exits):
I am involved in the Design and Engineering of a very large, new Industrial project (+375,000 sq,ft. , then 230,000 sq. ft. in future).
The customer will have a Generator, which will be used for powering loads designated as "Emergency Loads" (critical loads).
We (the Electrical Design Team) wish to drive the Emergency Egress area lighting from the Generator, as opposed to having the typical Unit Equipment installed for the "Emergency Lights".
(FYI: "Unit Equipment" = Fixtures with Battery Back-up Ballasts included within the fixture assembly).
The problem with using Unit Equipment is there will be close to 100 Emergency fixtures installed in Freezer / Cooler areas, having normal ambient temperatures of -20º C on average.
In these situations, the Battery Back-up Ballast is normally mounted remote from the fixture (outside the Freezer "Box"), and an Insulated Panel Penetration is required at each fixture's location.
BTW:, the Exit signs will be Unit types, and will be on the General Lighting circuitry.
Will it be compliant to not have Battery Back-up Ballasts on the Emergency Lighting Fixtures, and have them driven from the Generator "Emergency Power" Panelboards?
In County of Los Angeles, we had to use Unit Equipment + connected to the Emergency Panels - but this was for a high rise Commercial Building.
Any responses are greatly appreciated.
Thanks in advance.