I was asked to troubleshoot a supposedly non-functioning electrical cut-off situation in a restaurant fire-suppression system. I traced the wiring to an ITE load-center panel, where a 200a or 225a breaker feeds a panel in an adjoining section.
There are three black wires and one white wire emerging from the back of the breaker. Two of the black wires are taped off, and the third black and the white wires land on a 2-section barrier strip. I measure 120v between the black and white wires.
The complaint is from the fire marshal, that the electrical equipment does not de-energize when the system is tripped. The white is grounded, while the black is hot, returning from the fire suppression system. Here is my question:
Do all shunt-trip breakers trip when 120v is fed into the breaker, or do some trip when the 120v is removed? When I disconnected the wire returning from the system control box, nothing happens. Why are there four wires out of the breaker?
As always, any info is welcome. :smile: Danke!