kona20001
Canada
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Joined: 07/09/2008
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HI,
I am new to this forum and have looked through the FAQ and have been unable to get an answer to my question.
I have a Jazz 2760 5th wheel and I am wondering if anyone knows if a roof A/C will be damaged if you operate it on the low speed setting when connected to a 15amp circuit (this is what I plug into at my residence)?
I know that the breaker will blow if it is turned to top speed, but does not blow if run on the low speed. I have been told by friends that if you run a roof A/C (13500 BTU I think)it will damage the A/C because it cannot draw enough power on the 15 amp circuit and will therefore damage the unit. Is this true?
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NGRRFan
Colo. Spgs., CO
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My trailer is sitting in my back yard right now plugged in with the air going.
Rich, Kim, and
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2oldman
WA
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It sounds like you're right on the edge of the capacity of that circuit. It's the voltage that is criticial in whether you'll damage the ac... but it's not the voltage itself, it's the increased amp draw due to a lower voltage.
If there's some way you can measure what the running voltage is, do that. And it should stay above 112 or so.
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tvman44
Southwest Louisiana
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As long as you are getting proper voltage you will be ok, just keep an eye out for freeze up.
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zigzagrv
Nazareth, PA
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I do it often when the mh is sitting in my backyard. Just be sure the voltage is ok and that no other appliances are on. Also, periodically check the 30-15 amp adapter to make sure it is not overheating. Had that happen once, but caught it before any damage was done.
Ron
2003 Gulf Stream Ultra Supreme 33'
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wa8yxm
Wherever I happen to park
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Low or High, likely won't make much difference.. If the breaker holds you are OK, just make sure the lines (Cords) are up to the job...
A 15 amp breaker may be feeding 14ga wire,
Nothin adds excitment like something that is none of your business
John is Near Kenwood TS-2000 housed in a 2005 Damon Intruder 377
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NCHornet1
Mt. Airy, NC.
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I did this for a while when I bought my first RV years ago, then I finally just put in a dedicated 30 amp outlet and now no worries. Cost ne about $30, not worth taking the chance if you ask me, the low voltage/amperage will destroy circuit boards slower and without warning, but more are destroyed from under power than over power ( spikes or surges).
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smkettner
Southern California
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Watch the voltage in the RV stays 110+. Otherwise it is fine.
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Ray,IN
IN, USA
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Much depends on the extension cord, like the lifespan of your A/C compressor. Go to most any box hardware store and buy a "kill-A-watt" line voltage monitor, insert it between your A/C plug and the receptacle. Safe line voltage is 120VAC + - 10%, or minimum 108 and maximum 132VAC. Outside those parameters you are damaging inductive-load motors and sensitive electronics.
Use this wire size calculator to select the correct size/length extension cord.
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wa8yxm
Wherever I happen to park
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Short answer.. The number of AMPS on the breaker matters only in that if you try to draw 20 amps on a 15 amp breaker you will hear a CLICK and.. Nothing works (The breaker trips) no damage is done so long as you wait at least THREE MINUTES before re-starting the A/C
However the size of the extension cord (and other wires) is another matter, A/C's like to have more than 105 volts.. if you use common cords you can quickly drop below that when you use bit ticket items.. I suggest you either use 30 amp cords for as much of the run as you can or get a 12ga outdoor cord from Sears or K-mart (they have 'em with lock-on outlet ends, very nice)
Here I have around 50-60 feet of 12ga UF feeding a 30 amp outlet (20 amp breaker) feeding about 2 or 3 feet of adapters to my 50 amp rig (Confused)
Loss figures courtesy of SNOWMAN
Short version, I have 50-60 feet of 12ga Romex feeding the rig.
The Autoformer does not kick in when I turn on the A/C
A 1500 watt space heater won't kick it in either.
No-load voltage is around 126 per the Kill-a-watt, goes down to around 118 under load. Let me do some math Voltage drop for 12 ga wire, 50 feet, 12.5 amps is about 2, Voltage drop will increase with amps so 6.25 maps = 1 volt, 18.75 amps = 3 volts
If you have a 50 foot 12 ga cord and 120 volts at the outlet (And no more than 50 feet of 12 ga feeding the outlet) you should be good
NOTE voltage drop increases with length of cord as well 100 foot would drop 4 volts at 12.5 (Which is close to what an AC draws running)
Start current however is much higher Using 50 feet of cord plus 50 feet of 12ga inside the house you might drop 10-15 volts on startup This is right close to the limit. Again shorter wires = lower drop, Larger wires = lower drop
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