alananddena
Member
- Location
- Matthews, Missouri
I recently was at a grain elevator installing a PLC for some control and interlock solutions in a 480VAC control cabinet for various bucket elevators and drag conveyors, at first glance this cabinet looked clean and professionally wired. When I turned off the disconnect and locked it out I found that the control circuit was still energized and the cabinet sourcing all the motors did not have its own control transformer. Tracing down the control power source I found it to be five separate 20 circuits deriving from a nearby 240/120 distribution panel. I am unsure of why this cabinet was done this way because total load of the contactors coils is 7 amps if all were energized at once. I think this is a safety nightmare for there maintenance personnel, and I am looking for some standards for this in OSHA, and NEC but so far have come up with a bunch of refer to's.