Thor Forums

[16ACE27]

Originally Posted by steve2777

If I tested between the neutral bus and each circuit breaker's black wire contact screw, every circuit EXCEPT the a/c circuit showed a reading of between .05 and .5 kohm.

You are measuring parallel paths through loads at the other end of the circuit:
50 to 500 ohms.

Originally Posted by steve2777

But the a/c circuit showed a reading of .5 mohm.

That would be 500,000 ohms and is probably a good reading.

Originally Posted by steve2777

Sounds from what you're saying that, if anything, there was less resistance in the a/c circuit than the other circuits. But maybe I'm barking up the wrong tree.

No, there's MORE resistance in the A/C circuit than what you measured in the other circuits.

If the repair shop did nothing else but replace the A/C, and the new A/C is wired correctly, then you have a bigger wiring problem somewhere, like maybe an open ground to SP.

Your neutral and ground buss should NOT be bonded in the RV. You can test this with your ohmmeter.

They are bonded in the house's main control panel, or in the RV parks main distribution panel. They are also bonded in your RV's generator.

So if you have a problem in the wiring to your A/C - say, a screw is shorting the hot lead to the ground cable, but you have an open ground connection in your SP cable, the A/C would still run normally but you may also be energizing the ground of your RV - a "hot skin" condition.

But when switched to the generator which does bond the ground and neutral, that same screw creates a short circuit and overloads the generator. The fact that it does not happen until you turn the A/C on makes it seem like the short is in the A/C itself and not the wiring to it.

At this point I think you are beyond the non-electrician handyman DIY stage and need onsite electrical expertise troubleshooting. A good mobile RV tech or electrician should be able to help troubleshoot this issue.

You need to verify the wiring from your RV's main panel, back through the ATS to the end of the SP cord is good. This is most important as "hot skin"/open ground is a dangerous thing.

You need to verify the wiring from the RV's main control panel to the A/C, through the controller and relays, to the fan motor and compressor is good as well.

Good luck and let us know what you find out.

All connections in the ATS need to be verified correct and good as well.