Arc Flash Hazard Result

[jar546]

This is a photo of a 800 amp variable frequency drive, known as VFD. It looks like the B phase of this 480 V system let loose and you can see on the second photo all of the arc digits on the inside of the cabinet. I’m just happy no one was standing in front of it when it let go.

 

[ICE]

Is the cause known?

 

[jar546]

Is the cause known?

Not by me. I have to get follow up on this but will let you know. It tripped the breaker directly above it and the feeder breaker at the service to this panel too. That part has me curious.