auxillary switch from handle of 480v disconnect to ERU

[let the light shine]

I'm puzzled on the wiring of this 2NO 2NC
electrical interlock auxillary switch from the
480v line side of power to the ERU unit which
operates off of DC power derived from the elevator
controller. I'm told by the elevator tech that when main power is lost, the ERU will call the
elevator down to the lobby and open the doors.

I understand the principle of the elevator's
ERU, what I don't understand is how will a 480v
feeder tie in with a 120v dc unit fed from the same source without exploding? The disconnect
is a Cutler-Hammer 200a Fused to 125a. The auxillary contact is a C-H DS200EK2.A wiring
diagram would help greatly.


Thanks,
Let the light shine