After being left all alone in the rain for four months in the rain forest, we came back to find that there was a short in the AC system in our 1979 31ft Sovereign. A little trial and error in the "fuse" box isolated the problem to a white wire connected directly to the AC in, and whose matched black wire went through a breaker labeled "air conditioning". Now, the circuit I plug in would blow even with the breaker on OFF, so I'm guessing that there's a short between the "white" line and ground. The only way to avoid blowing the entire circuit was to disconnect the white line (and isolate it, naturally).
1) Does my diagnosis of a short between the AC circuit and the ground make sense?
2) any idea how to figure out where the short would be? I'll clearly need to go on the roof some sunny day and take apart some of the AC unit, as that's the most likely place for some bad water pooling, but any hints appreciated.
... Now, the circuit I plug in would blow even with the breaker on OFF, so I'm guessing that there's a short between the "white" line and ground. ...
What exactly 'blows' when the breaker is off? Normally, a fuse 'blows', and a breaker 'trips'. Can you rephrase?
If you follow the wiring back to the house/campground, you will note that the white wire (neutral) and the ground wire are electrically tied together at one point. So a short between the two connectors may or may not be noticeable.
I'm currently plugging in to an outside outlet of my neighbor's via an extension cord. The breaker on his outlet trips as soon as I plug in, if and only if the AC line is connected (in the electrical box in the trailer).
I'm currently plugging in to an outside outlet of my neighbor's via an extension cord. The breaker on his outlet trips as soon as I plug in, if and only if the AC line is connected (in the electrical box in the trailer).
Does that help?
--david
SO this is AC-alternating current, not AC-Air Condintioning, right?
1) Yes, this is an extension cord off of 20A or so. However, it's worked fine for months. Only recently did connecting cause the breaker to trip. It's a heavy duty outdoor extension cord rated for 30A or so IIRC. The extension cord itself tests fine.
2) This is a "parked" unit -- I only run on 110V AC. (the batteries are disconnected, I think).
3) If I don't disconnect the white wire to the air conditioning loop, the breaker trips even with all breakers in the Airstream off. The breakers are all inline with the "black" wires, which is why I'm guessing that there's a short between the white wire and the ground. If I disconnect the white wire to the air conditioning loop, then I can flip the breakers on and everything works fine (lights, furnace, hydraulic jack, etc.).
I did test the continuity of the breaker associated with the air conditioning system (I was thinking like you that the breaker was the problem), and it is working ok. (I didn't test all of them, I'll do that next time I'm there).
Still, I'm not sure I understand. If my hypothesis of a short between the white line and ground is correct, wouldn't that current loop bypass all of the breakers which are on the black wire?
... If my hypothesis of a short between the white line and ground is correct, wouldn't that current loop bypass all of the breakers which are on the black wire?
No.
David, I think you have more than one problem. The best starting place is to be able to plug your airstream into shore power without blowing your neighbor's breaker.
I'd love to plug in to real shore power, but for that I have to build a shed, get the electric co to setup a meter and run a line from the pole, etc, and that'll take a couple of months =)
I get to the trailer only every few weeks, so I'm trying to "store up" as much info between visits as I can, especially since I don't have good net access there.
So far, I plan on checking each of the breakers, and testing for shorts between the suspicious lead and whatever wires I can get my ohmmeter on.
Oh, one other thought that could explain why my breakers don't trip but the neighbor's does is that it could be his is rated lower, so his trips first, no?
I was drawing out the schematic on the board to try and understand what might be going on, and I just wondered something. If my neighbor's outlet was miswired and what my airstream thinks of as the neutral is actually live, wouldn't that explain why the breakers aren't having an effect?
Let me get this straight.
All is well until you wonnect the white wire in the breaker pannel in the trailer to the white wire buss strip?
If that is the case, go to the AC unit where the electrical wires hook into the wires of the AC unit and see if there is anything amiss. If every thing looks alright disconnect the black, white and green wires from the AC. Tape the black white and green wires comming from the breaker panel(in the trailer).
Hook the white wire back up in the breaker panel (in the trailer). Plug the trailer back in to your power sourse and see if every thing is alright.
Let me know what happens.
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