dwanderson
Member
We are adding motor control panels to an existing system of motor control panels. The 480vac power source for our new motor control panels is fed from a different power source used to feed the existing motor control panels.
We have to run interlock wires between the old and new motor control panels and see a 220volt difference of potential between the hot wires from each system. We didn't realize this until we blew up a PLC input card in one of the existing system's motor control panels.
What if an NEC codes address this situation?
I think we will have to install a junctiom box with relays to keep the wires of different potentiol out of the motor control panels, but we just move the problem to the junction box. Is this alowable per the NEC?
We have to run interlock wires between the old and new motor control panels and see a 220volt difference of potential between the hot wires from each system. We didn't realize this until we blew up a PLC input card in one of the existing system's motor control panels.
What if an NEC codes address this situation?
I think we will have to install a junctiom box with relays to keep the wires of different potentiol out of the motor control panels, but we just move the problem to the junction box. Is this alowable per the NEC?
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