tony_psuee
Senior Member
- Location
- PA/MD
I was recently at a jobsite with the following wiring configuration:
Two 460V VFD feeds from the MCC are run in a common conduit with a single EGC into a junction box. In that box the EGC is bonded to the RMC and then it continues with power feed to VFD #1. The EGC is landed on VFD #1 ground and run back into the junction box. In the junction box it is part of six #10AWG cluster in a Blue wire nut. An EGC is run into VFD #2 ground and another is in an RMC run to VFD #1 disconnect through a ?T?, terminates on the ground lug. From that ground lug an EGC is run up to motor #1while another EGC goes from the ground lug back into the RMC and T?s over to VFD #2 disconnect. I have the following question, should the RMC entering the motor disconnects also have a bonding jumper? I did not see any notation in the disconnect that stated it was listed as suitable for bonding. I have looked at 250.96 and 250.97 and it appears to me that a bonding jumper is required where the RMC enters the motor disconnect through a factory eccentric knockout. The entire EGC set up looks bush league to me, and I am now trying to research if it is completely code compliant. Any feedback is greatly appreciated.
Tony
Two 460V VFD feeds from the MCC are run in a common conduit with a single EGC into a junction box. In that box the EGC is bonded to the RMC and then it continues with power feed to VFD #1. The EGC is landed on VFD #1 ground and run back into the junction box. In the junction box it is part of six #10AWG cluster in a Blue wire nut. An EGC is run into VFD #2 ground and another is in an RMC run to VFD #1 disconnect through a ?T?, terminates on the ground lug. From that ground lug an EGC is run up to motor #1while another EGC goes from the ground lug back into the RMC and T?s over to VFD #2 disconnect. I have the following question, should the RMC entering the motor disconnects also have a bonding jumper? I did not see any notation in the disconnect that stated it was listed as suitable for bonding. I have looked at 250.96 and 250.97 and it appears to me that a bonding jumper is required where the RMC enters the motor disconnect through a factory eccentric knockout. The entire EGC set up looks bush league to me, and I am now trying to research if it is completely code compliant. Any feedback is greatly appreciated.
Tony