Is it OK to use a local lighting circuit to supply battery packs and exit signs?
No it is not ok. Rule 46-400(1)(2) is pretty clear about that
Maybe a better way to put or pose the question would be " Why shouldn't battery packs and exit signs be fed from a local lighting circuit?". What technical problems could arise from such an installation?
Well they shouldn't be fed from a local lighting circuit because it would be illegal.
Maybe the intent is to eliminate as many potential mistakes as possible such as having a switch or timer in the circuit. Who knows, maybe sometime down the road someone will decide to place the complete lighting circuit on a timer without realizing the exit signs and emergency lighting is on the same circuit. I am just taking a guess at the reasoning though.
