Lazy Daze Owners' Group

Air Conditioner Power Question

January 31, 2016, 06:32:18 pm

Yahoo Message Number: 158446

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I'm just a little bit confused about running the air conditioner on a 15 amp circuit. If I use a heavy enough extension cord and can connect to the 30 amp connector on the LD, is it safe to run the air conditioner?  I thought the LD manual says that this could cause damage to the A/C?  Yet if the A/C operates on a 15 amp circuit, why can't I use a heavy duty extension cord connected to a 120V connection, which is a 20 amp circuit in my house?  I'd sure like to be able to run the A/C in the summer while getting it ready for trips, without installing 30 amp service.

Ed & Margee Eisenhower State Park, TX

Re: Air Conditioner Power Question

Reply #2 – January 31, 2016, 11:00:28 pm

Yahoo Message Number: 158448

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Hi, Ed--

I ran the AC when I was plugged in at my aunt's home last summer (& a space heater later in the fall), using an adapter like the one shown in Chris's response.  I had to learn not to use the microwave & AC at the same time--half-popped popcorn doesn't finish popping after I went stumbling around in the dark with a flashlight to reset the GFCI outlet under the deck...but the birds cleaned up the old maids the next day.  Also, I plug in here at home so I can get the fridge cooled down when I'm prepping to head out, & have had no problems.

Lynne LDy Lulubelle, '05 30' TB Lilly, 4-Legged Alarm

Re: Air Conditioner Power Question

Reply #4 – February 01, 2016, 02:26:25 am

Yahoo Message Number: 158450

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"I'm just a little bit  confused about running the air conditioner on a 15 amp circuit. If I use  a heavy enough extension cord and can connect to the 30 amp connector  on the LD, is it safe to run the air conditioner?  I thought the LD  manual says that this could cause damage to the A/C?  Yet if the A/C  operates on a 15 amp circuit, why can't I use a heavy duty extension  cord connected to a 120V connection, which is a 20 amp circuit in my  house?"

Here is the issue:
 The 15A A/C circuit in the rig is a short run from the breaker to the unit, so if the 30A circuit to the panel has correctly sized wiring, that 15A breaker will see essentially 120 VAC. Even with 14 gauge wiring to the unit, voltage drop should be minimal at the A/C. However, if you connect the 30A shorepower cable to a 20A circuit, the voltage drop at the panel will be much higher under load, and under extreme conditions of low voltage, the additional voltage drop could be enough to damage the compressor. A household 20A circuit will likely use 12 gauge wiring from the breaker panel, and a good 30A circuit typically uses 8 gauge.

Steve

Re: Air Conditioner Power Question

Reply #6 – February 01, 2016, 09:11:50 am

Yahoo Message Number: 158457

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I fear the charts in are more likely to confuse than inform the typical RV owner. The first chart is for bare wire, which we do not use in our RVs, and the second chart is for Teflon insulated wire that we do not use either. Ampacity varies considerably with the wire's insulation, the operating temperature, and whether wires are free-standing or bundled, and using charts like this without training or experience will lead to potentially serious mistakes.

Here's my analysis:

* For 120 vac wiring, a person capable and comfortable with doing wiring changes in their house can also do so in their RV.
* For safe high current (anything over 30 amps) 12 volt DC wiring needed for inverters and chargers, you should be very knowledgeable or have someone that is checking your work. Undersized wiring is inefficient at best, and can be a fire hazard at worst.
* Effective, efficient solar panel wiring can be determined with some research by the less experienced, and using too small a wire size is not a safety hazard, as it would be with 120 vac or high current 12 volt DC wiring.
* Most people can safely do low current (10 amps or less) 12 volt DC wiring with some help; e.g., adding a power socket, a lighting fixture, a vent fan, etc.

Eric Greenwell
  [lifewithalazydazerv] wrote on 2/1/2016 6:04 AM:

Re: Air Conditioner Power Question

Reply #8 – February 01, 2016, 09:58:09 am

Yahoo Message Number: 158459

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" using charts like this without training or experience will lead to potentially serious mistakes."

---- Agreed, of course, but one would hope that anyone reading the AWG wires size/type charts would have the sense to recognize his/her "wire savvy" limitations and do further research, skill-building, and/or expert assistance before tackling projects, particularly "sparky stuff" projects, that are beyond their reach? ;-)

Joan

Re: Air Conditioner Power Question

Reply #10 – February 01, 2016, 11:41:41 am

Yahoo Message Number: 158464

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I've heard a few horror stories over the years about electricians who were unfamiliar with the RV outlet type, or just "thought they knew better."

--- Yes, I had an encounter with one of these: "RVs use 220V, just like your washer and dryer." Uh huh. (I suspect that this thinking was the cumulative result of brain jolts from mis-wired outlets.)

Joan

Re: Air Conditioner Power Question

Reply #12 – February 01, 2016, 12:32:50 pm

Yahoo Message Number: 158468

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One thing to note here is when it comes to 240V wiring, the plugs, sockets, etc are common to a household standard. The expression 220 VAC comes from an earlier vintage when 110 VAC was more common in homes due to line drops, etc. However, it is the same split-phase service that is now referred to as 240VAC for home or RV. Single-phase 30A service is a different animal.

Steve

Re: Air Conditioner Power Question

Reply #14 – February 01, 2016, 02:13:35 pm

Yahoo Message Number: 158470

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We moved into a new home just after we bought the LD and I had the builder install a 30amp plug in the garage. All went well except it was installed upside down! I even provided an internet photo of the plug. Well, it works and surely is handy for loading, unloading and working on the LD.

Chris

Re: Air Conditioner Power Question

Reply #16 – February 01, 2016, 09:52:39 pm

Yahoo Message Number: 158475

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I suppose it's easy to see why I said that this matter can be a bit confusing.  In fact, it makes my head hurt.  It would certainly be wonderful to have 30 amp service at the homestead, but not this year.  Finally, I'm mighty pleased that cleaning the black tank of "solids" is easier to understand than electricity!  Otherwise, we'd be up to our necks in "solids." 

Please know that we're sure appreciative of all the guidance and feedback from the Faithful.

Ed & Margee Back Home in Fort Worth

Re: Air Conditioner Power Question

Reply #18 – February 02, 2016, 04:45:09 pm

Yahoo Message Number: 158488

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Those are also the charts I refer to for inverters and solar charging - easy to use and understand.

Eric
  [lifewithalazydazerv] wrote on 2/2/2016 9:27 AM: