Posted 2009-05-15 12:00 PM (#104973) Subject: electical ? on used diy
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Posts: 11
Location: Minnesota
I bought a used trailer from a dealership that someone had finished the dressing room themselves. It has a regular outlet on the outside to plug in (3 prong like in your home) and inside 3 outlets, AC unit, and 3 lights that run off this electricity. I tried plugging in somewhere and could not get anything to work (with a 15A 12g ext cord). I was at the dealership this week, he plugged in and everything worked - well, we blew the breaker when we turned the air on. They guy said to make sure I have a 30A cord.
So, now I've been looking and I can't find a 30A cord that has the plain 3 prong connection. What can I do? Should I redo the outlet to a 30A connection? I learned it's pretty hard to run an AC unit on 15A.
Posted 2009-05-15 3:29 PM (#104984 - in reply to #104973) Subject: RE: electical ? on used diy
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Posts: 2957
Location: North Carolina
You've said you have an inlet with the household plug pattern. That is rated at most, 20 amps. Use it for an extended time at 30 amps and the connection will overheat. Using a 30 amp RV cord doesn't change the weak link. Using a heavy cord does minimize voltage drop over long extension cords. (a good thing)
When you operated the a/c unit was anything else on in the trailer? I'm betting your circuit at home was already loaded and the additional load of the a/c unit was too much.
Posted 2009-05-15 3:46 PM (#104985 - in reply to #104973) Subject: RE: electical ? on used diy
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Posts: 5870
Location: western PA
If you plug a 30 amp line into a 20 amp circuit, you will only get maximum of 20 amps, and not over heat the line. The standard plug design of the adapter is only designed for a maximum of 20 amps. You can always draw less than the wiring's capacity.
Posted 2009-05-15 5:16 PM (#104990 - in reply to #104975) Subject: RE: electical ? on used diy
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Posts: 5870
Location: western PA
[ I'll have to check the circuit breakers inside - they should be 30 amp as well?
I doubt that your interior wiring is of 10 awg. If it is equipped with 12 awg, your breakers shouldn't exceed 20 A on each circuit. If you have 14 awg installed, your breakers should not exceed 15 A on each circuit.
If your AC circuit is protected with a 15 A breaker, it may trip upon a start up.
Posted 2009-05-18 12:36 PM (#105077 - in reply to #104984) Subject: RE: electical ? on used diy
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Posts: 11
Location: Minnesota
Originally written by hosspuller on 2009-05-15 3:29 PM
You've said you have an inlet with the household plug pattern. That is rated at most, 20 amps. Use it for an extended time at 30 amps and the connection will overheat. Using a 30 amp RV cord doesn't change the weak link. Using a heavy cord does minimize voltage drop over long extension cords. (a good thing)
When you operated the a/c unit was anything else on in the trailer? I'm betting your circuit at home was already loaded and the additional load of the a/c unit was too much.
This is why I was thinking I'd have to rewire the plug. We had the lights on, nothing in the outlets and the fan. Switched over to the A/C and it tripped the wall connection.
If I ever want to run the A/C with anything else - I'll have to redo the plug, right?
Posted 2009-05-18 2:42 PM (#105086 - in reply to #104973) Subject: RE: electical ? on used diy
Expert
Posts: 5870
Location: western PA
Your wall circuit isn't providing enough amps. To run many AC units, you have to have a 20 A circuit all the way to your AC unit. If the supply to the trailer cord isn't sufficient, the starting load will trip the wall supply breaker. If it is wired with 14 awg wiring or has a 15 amp breaker, it will be insufficient when combined with your line loss.