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LOFAT36's avatar
LOFAT36
Explorer
Apr 16, 2016

AC question

We have a 33'-0 5th wheel with single AC. When plugged in at home will the AC function properly if plugged into a 15 Amp outlet ? If so, I usually have a normal extension cord running from the 5er's plug to the outlet. Any comments ?
  • We have run the A/C from a 15A outlet, but turning on anything else can pop the breaker.
    Run the big RV extension cord all the way to the conversion plug at the wall socket.
    When the circuit breaker pops, wait 5-10 minutes before you start the a/c again.
  • Thanks for the input. 13,500 BTU'S and I'll drop the extension and run my main cable to the outlet.
  • Most standard extension cords have 5-15 cord bodies. This is the NEMA standard for 15 amp.
    A true 20 amp is a 5-20 Nema configuration where the male end has the neutral perpendicular to the phase blade.
    Big thing is the gauge of the wire. Larger gauge is better. Minimum 12 gauge is best. Cord bodies are the weak point.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    I would consider upgrading that extension cord.. Sears (And K-Mart) both sell a 12ga cord which is designed for indoor/outdoor use, This cord is different from the nearly identical cords sold at Home Depot, lowes. Ace Hardware and .. most everywhere else, in that there is a push button on the outlet end that must be pushed when plugging into the cord or unplugging from it.

    Thus I recommend it

    But any good 12ga cord is better than the 14 or 16Ga "Standard" cords.


    I have 3 of those 12ga cords

    one is 100 ', the others are 10 and 20.
  • We ran a 50' heavy duty (15 Amp rated) extension cord from our rig to a 15 Amp outlet for over a month with no problems. We ran a 13.5K a/c a lot (it was DC during the summer). You must make sure than any other large load is off (no microwave, water heater, battery charger, etc).
  • Learjet wrote:
    15 amp is no good in my opinion...you need minimum 20 amp with no other loads on the house circuit and no other loads on in the RV expect the converter with fully charged batteries.


    The OP is here in Canada where 20 amp circuits aren't the norm as they are in the US. He hasn't told us anything about his A/C unit but if it's a 13,500 BTU then as long as the source voltage is a nominal 120 vac, the cable run isn't excessive, and he uses his main service cable instead of a small gauge extension cable then he'll be able to successfully start and run that A/C just fine on a 15 amp circuit. As you yourself say - "I do it all the time". ;) OTOH if his 5th has a 15,000 BTU A/C, or nominal voltage is significantly less than 120 vac, or he does use an excessively long, small gauge extension cable then his chances of success are much diminished. Without knowing these details which the OP hasn't told us it's impossible to answer his question accurately.
  • I usually pop the breaker on a 15 amp circuit, 15Kbtu AC unit. Any extension cord should be 12 gauge, not a "normal" extension cord. Sometimes it works for a while though.
  • Answers will vary. I am guessing you have a 30 amp rig!
    Extension cord needs to be a healthy size. a standard 16 or even 14 gauge cord would not be adequate. 12 gauge or a standard 30 amp RV extension cord would do better. The 30 amp extension cord could come in handy on the road.
    Charge up the batteries good before running AC should reduce the load and keep voltage levels up a little.
    How far are you talking?
  • 15 amp is no good in my opinion...you need minimum 20 amp with no other loads on the house circuit and no other loads on in the RV expect the converter with fully charged batteries. Maybe a low wattage TV on would be OK.

    And yes I have done this many times on a 20 amp circuit.
  • Maybe but maybe not depends on the size of the ac and how long the extension cord is.

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