Dead short

[Castor Troy]

I'm new to a company in Nevada. Prior to my arrival last week, there was a power outage with a tripped breaker 175 amp (sub panel) and it also tripped the main 3k amp. It appears that the contactor went phase to phase to phase. A-B-C I have no drawings or schematics; it appears this cabinet was hand made and piecemealed together. I'm tracing the primary and secondary wires from the contactor. With an Ohm meter I'm reading a "short" between A phase and C phase on the primary and A phase and B phase on the secondary. But I may be reading across two separate transformers. I realize this is scattered information but has anyone come across this type of scenario before? Advice? I removed the contactor to take it out of play; I still have the same readings on the wire.

 

[hillbilly1]

So on the line side of the contactor you are reading shorted between A and C, but not on the load side? And on the load side you have a short between B and C? Have you checked for continuity between the line and load contacts on the contactor? Is this contactor feeding a transformer? Or a panel?

 

[4x4dually]

If transformers are still connected, you are gonna have phase to phase shorts on a DMM.....maybe I'm stating the obvious here.

 

[LarryFine]

Welcome to the forum.

Are you sure you're reading a short, or could it be the low impedance of a transformer coil or a load?

 

[Castor Troy]

The contactor feeds a motor. I rang the contactor out, top to bottom and and doesn't ring true. I'll order a replacement contactor and follow up.
And yes, I was reading through more than one transformer.
Thank you everyone