Forum Discussion

Explorer

Sep 19, 2015

ATS (Automatic Transfer Switch) fried?

Last time out with the fifthwheel I saw a flash out of the corner of my eye when I had the basement door open coming from the vicinity of the ATS. Everything in the trailer kept working but I can't remember if I used anything that was 110 volt.

Today I bring the trailer home to work on it. I plugged the power cord with 50 amp surge suppressor in which then puts on its time delay light. After about 3 minutes the suppressor starts making a clicking sound and vibrates for about 10 seconds then stops. It pops the house breaker to the outside outlet which is the one I normally use with the trailer. When I plug in the trailer line without the suppressor and switch the house breaker on, it pops immediately.

I took the cover off of the ATS and I see nothing to indicate a flash has occurred inside of it or on the outside around it. Any suggestions on what I can check next? I don't want to buy a new ATS if I don't need it.

23 Replies

duggram
Explorer
Sep 19, 2015
Thanks for the quick replies. I was hooked up to a 15 amp 110 volt outlet and my EMS is in the line from the house to the trailer. With the main breaker in the trailer turned off my multimeter shows continuity from L1 to L2. However when I disconnect my 50 amp cable from the trailer, that wasn't plugged in at the other end, there is no needle movement at all between L1 and L2. Does this indicate a short in the cable?
time2roll
Nomad
Sep 19, 2015
Turn off the main breakers in the RV. You should then have no continuity between the plug L1-L2 also no continuity between L1-N or L2-N.

Post the results. Next will be disconnecting wire to isolate the short.

Do not continue to plug into 50 amps to verify if the short has been isolated.
Bobbo
Explorer III
Sep 19, 2015
If you are popping the 50 amp breaker at the house, you have a dead short. Unplug the RV until you track it down!

Hint: Since it doesn't pop until after the EMS connects, the short is AFTER the EMS.

You don't say if the EMS is before or after the ATS. If it is after the ATS, then the ATS is not the culprit. If it is before the ATS, the ATS is still a suspect.