Run AC on 15 Amp at Home?

[Max23]

Originally Posted by NH_Bulldog

I have purchased wiring by the foot from Lowes and Home Depot. I just did a search at HD and you can get Romex 10/2 w/ground for $1.98/ft and free shipping.

Thanks for the suggestion. Never even seen anything in store about buying it by the foot. That could be just what I'm after. Thanks!

[rhagfo]

Originally Posted by PolarisCobra

In my case, the outlet is one I added in my garage for an air compressor. It is a dedicated 20A line, properly wired, only the one plug in the garage is on the circuit. I know enough not to run the air compressor if the trailer is plugged into the outlet.

I understand that there are a number of people who would suggest that it is a bad idea, and I would say that I value your opinion.

Can anyone chime in who has connected their 30 Amp plug into a 15 Amp circuit, run the AC, and actually had a failure, or experienced what they believe was a premature failure?

So one question you haven't answered, how far is the camper from said outlet?
The camper sounds like a 30 amp service unit, I would use the full length of the 30 amp camper cable, then only a 10 gauge extension cord long enough to make up the distance between the outlet and the camper cord.

[notanlines]

Max, all the Home Depot’s, Lowe’s and Menard’s that I know of, even in the middle of nowhere, have wire by the foot.

[PolarisCobra]

That is my plan. Use the 30 amp cable from the trailer, then extend as needed to get to the plug, with a 12 gauge cord. Will try it, and watch the voltage in the trailer when I try it, to make sure there is no voltage drop.

[rhagfo]

Originally Posted by PolarisCobra

That is my plan. Use the 30 amp cable from the trailer, then extend as needed to get to the plug, with a 12 gauge cord. Will try it, and watch the voltage in the trailer when I try it, to make sure there is no voltage drop.

You don't mention distance, I would look at either buying or building the necessary length of extension out of 10/3 cord.

Here it is from HD https://www.homedepot.com/p/Southwir...2599/204633009

[JBM3M]

Gonna be mighty hard to 'monitor' voltage drop as when the compressor kicks in, it is very quick.



You still have not addressed the distance from the 20 amp to the RV cord and length of RV cord. Adapters are notorious for causing resistance in a circuit.


You should be okay, if you use large enough wire for the distance. Additionally I would suggest a Micro Aire easy start regardless of what you do. They really cut down on the surge and will benefit your AC unit regardless of the input. I have one on each AC unit on my 5th wheel and put one on my home AC also, it makes that much of a difference.


For RV:
https://www.microair.net/collections...r-conditioners

[PolarisCobra]

Trailer will be behind garage, with the hitch end closest to the garage. So - the 30 ft cable that comes with the trailer will reach from the back to the front. Will need most of a 50 ft cord to reach the plug.

[sourdough]

Are you saying you will have 80' of cable? The 30' of the trailer cable plus 50' extension cord? If so you really need to forget any kind of 12 gauge cord/cable.

[notanlines]

What Danny just wrote^^^^. The difference in price for 50 feet of 10 vs 12 gauge is about $25. Go with the 10 gauge.

[wiredgeorge]

Seems to me if this is where the trailer will be parked you could hire a bona fide electrician and run a 30A service to an outdoor 30A outlet on the back of the garage.

[rhagfo]

Originally Posted by notanlines

What Danny just wrote^^^^. The difference in price for 50 feet of 10 vs 12 gauge is about $25. Go with the 10 gauge.

Well you could order an RV 30 amp extension cord or a 10/3 standard extension cord like the following.

https://www.lowes.com/pd/Southwire-5...ord/5013119451

[PolarisCobra]

Originally Posted by sourdough

Are you saying you will have 80' of cable? The 30' of the trailer cable plus 50' extension cord? If so you really need to forget any kind of 12 gauge cord/cable.

Yes the total length gets to 80 feet in this example, but it seems to me that the 30 foot cable that is part of the trailer is not part of the problem. That cable is part of the design of the system, and already accounted for.

I would only be adding the 50 ft 12 gauge cord, running the fridge on gas, no microwave. It seems like this should be doable on a dedicated 20 amp circuit.

[Don77]

I wold not do it for All the reasons stated above!
Don

[PolarisCobra]

Thanks for the advice.

[JRTJH]

Originally Posted by PolarisCobra

Yes the total length gets to 80 feet in this example, but it seems to me that the 30 foot cable that is part of the trailer is not part of the problem. That cable is part of the design of the system, and already accounted for.

I would only be adding the 50 ft 12 gauge cord, running the fridge on gas, no microwave. It seems like this should be doable on a dedicated 20 amp circuit.

Isn't that the same as saying, "I have a blue 2x4 that's 8 feet long. If I lay a green 12' 2x4 at the end of it, I only need enough red paint to paint the 12' part to make it all red" ???? You have to consider the entire length of board, so you'll need enough red paint to paint 20' of 2x4.

Ot's the same with electrical cable. If you "plug a 50' extension cord to a 30' cord" the total length of run for electricity "at the house plug" is 80'. It doesn't "just stop and wait at the end of the 50' cord or get a "free pass the rest of the way". It has to travel through the resistance of that other 30' as well before it can run the air conditioner, and the total resistance of the entire length of wire is what determines the voltage drop from point A to point B.... It doesn't matter that the first 30' was "already there", when you add to that 30', the ENTIRE length is what the electricity must travel through to get from point A to point B.....

[Canonman]

CURRENT DRAW 20A MINIMUM WIRE GAUGE 12-gauge VOLTAGE DROP 3.33%

This is from an extension cord size chart assuming a 50' cord, a 20 amp load and 110 vac. So, at the end of the cord you would have roughly 106 volts. Pretty sure the trailer service cord is 10 awg so the voltage drop there would need to be added in.
A 50' 10 gauge extension cord can be purchased from Harbor Freight for about $75:
https://www.harborfreight.com/50-ft-...iABEgL9_fD_BwE

Having the larger gauge cord would be good, as there is still a 4% voltage drop at 100'
We seem to get by with our set up but I'm only using a 25' cord.

[rlh1957]

With a SoftStartRV box installed on AC and a 20Amp plug & circuit breaker you could run one AC. A15Amp is just to borderline.
Maybe w/ fridge and maybe not. Depending on start/run Amps needed by the fridge and if fridge & AC start at the same time.

You’ll really do yourself a favor to put in a dedicated 30Amp RV or 50Amp RV breaker and receptacle.

Just be certain your installer electrician acknowledges that 30A & 50A RV wiring is different than standard house plugs & circuits.
If they don’t agree to or know that, get another electrician.

[LHaven]

Originally Posted by PolarisCobra

If I connect it, and plug a voltmeter into a plug in the trailer when I turn the AC on, I should be able to watch for a voltage drop, which will give me an indication if I am going to have trouble.

An even better idea is to get yourself a true EMS unit while your rig is still new. It will not only tell you the voltage any time you want to glance at it, but it will shut down power to the rig if it is in any way hazardous to you or your equipment.

[PolarisCobra]

Got my trailer yesterday. Measured voltage at my 20A plug in the garage, reads 119 VAC. Plugged the 12 gauge cord into the trailer cord, and measured voltage inside the trailer, 119 VAC.

With the fridge off, water heater off, everything else off except a few LED lights, it turned on the AC. It did not seem to labor at all at startup, voltage dropped to 112 VAC in the trailer with it running. When I get it to a campground with a 30 A circuit, and no need for the extension, I will see if it sounds different, and what happens with the voltage.

Not something I would do all the time, and I may well consider adding a 30A plug on the outside of the house, but it made cleaning the trailer MUCH easier on a warm very humid afternoon.

[rlh1957]

Using volt meter to watch for voltage drop won’t tell you much, otger than being harder on an AC.
The real figure is amps being drawn on start up and amps being used while running.
If you can run an AC it most likely will be the only thing and will heat up that extension cord running at near capacity of a 15A circuit.
A 14gauge extension cord is not preferable, but 12gauge extension cord as short as possible from the outlet.
If the 15A house outlet has any other plugs on the circuit domething will trip the breaker in the house.