I need to feed an ALCR with 120VAC or 277VAC on the Normal Power Sense, but the fixture it controls is fed the other voltage via Emergency Power.
Would the ALCR be able to handle this and still remain under its UL 924 rating?
Yes, it can!
Because the ALCR is a Shunting device, and not a transfer device, it will pass along to the fixture whichever voltage is tied to Emergency Power In.
Inside the ALCR, there is no connection between the Normal Power Sense and Emergency Power In/Out. Connected fixtures only use the Emergency Power.