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pcskier · 06-03-2021, 05:42 PM

If I made a 200 foot extension cord with this cable to run ONLY my AC, would it get me by? According to online calculators, if I limit current to 20a, and allow for a 10v voltage drop from a 120v source, 10 awg is adequate. Am I missing anything here? This cable is 10/3.

https://www.amazon.com/Bulk-Cable-20...p?ie=UTF8&th=1

An older thread referenced Inland Andy using one that worked great, but he didnt mention what wire size it was.

ITSNO60 · 06-03-2021, 06:33 PM

The answer is not so simple. The AC compressor is rated at 115 volts and listing requirements dictate that it must be able to operate at plus or minus 10% of that. So your 200 feet of 10AWG will deliver 115.2 volts at 20 amps and 116.1 volts at 16 amps (provided there is a full 120 volts being supplied at the source), which is right in the ball park however you must also consider the run from where you plug it in to the main service, and from the main service to the transformer. If you are plugging in right at your house main this will probably be negligible unless your incoming service wires are unusually long and/or small. If there is another run of #10 between your RV outlet and your main all that needs to be added to the length. Once you are hooked up you can measure voltage at the trailer when your load(s) are running to verify. This is very important because you don't know what the power company is giving you at any particular time, if your neighborhood transformer is heavily loaded you could already have a voltage drop before you even plug in. If you know you have decent power being delivered I would probably go with the #10 but I would still monitor it, even though the motor rating allows you to drop as low as 103.5 volts I would not like to see that.

I paid $1.29/ft for that cable a couple of months ago at the supply house.

Belegedhel · 06-03-2021, 07:49 PM

You might also consider installing a Micro-Air EasyStart on the air conditioner--its a game changer in terms of the power required to run your AC.

good luck!

**wulfraat** · 06-03-2021, 08:43 PM

You will probably want a voltage regulator at the trailer. that is a LONG distance I'd be surprised if the voltage drop was only 10v. That would be without load best case I imagine....

bweybright · 06-03-2021, 10:10 PM

My question is what are you pulling the power from? When I put my shop in they ran 8 gauge (I think) to give me a 50 and 30 amp box in the shop, 100 ft. from where they pulled it in the main house. Now the main house has 400 amp service so how they pulled it I have no idea. I think they tapped into the main feed into the house which has the 400 amp from the street.

No real clue here but, just pondering?

GMFL · 06-04-2021, 06:31 AM

6AWG. 6-2 UF with ground it what you need. 200’ of 6AWG will maintain voltage with a 4.46% drop.

OTRA15 · 06-04-2021, 06:54 AM

Quote:

Originally Posted by GMFL

6AWG.
. . .

Yup . . . get the right tool and be done with it.

Avoid analysis paralysis.

Saving money on tools is usually a false economy IMO.

200' 6AWG extension cord.

A great investment for the rest of you life.

Life is short.

Live it well.

johndpolk37 · 06-04-2021, 09:38 AM

Quote:

Originally Posted by pcskier

If I made a 200 foot extension cord with this cable to run ONLY my AC, would it get me by? According to online calculators, if I limit current to 20a, and allow for a 10v voltage drop from a 120v source, 10 awg is adequate. Am I missing anything here? This cable is 10/3.

https://www.amazon.com/Bulk-Cable-20...p?ie=UTF8&th=1

An older thread referenced Inland Andy using one that worked great, but he didnt mention what wire size it was.

If this is a 1 time power cord (you're going to leave it in place, across the ground) then you will want something that is "sun rated" or at least "outdoor rated". The regular black jacket on the wire, you show will deteriorate over the years... If you are going to pick it up and move it often, then the wire you show should be OK.
Another, less expensive, option would be to get outdoor rated 10/2 (or larger) Romex. The 3rd conductor, for ground is included, so 10/2 is fine... and being 'outdoor rated' means it can stay outside, and even be buried at a later date!
https://www.homedepot.com/p/Cerrowir...862G/202304619

John & Roberta · 06-04-2021, 09:50 AM

At the end of the day, after you’ve attached your 200-foot 10/3 extension cord and operated your one air conditioner, take hold of the cord near where it enters the trailer (assuming the location is not in the sun)—if the cord is warm, you are pushing it. (Joule heating comes at the expense of voltage. A significant voltage drop will either shut down the AC or damage it.)

uncle_bob · 06-04-2021, 11:04 AM

Hi

Your A/C unit *might* have a surge current as high as 45 amps. You do *not* want a voltage sag at startup. That's how you fry the compressor motor starting winding. Roughly speaking, that cuts your loop resistance down to about 30% of the 15 to 20A calculations.

200' at 45A is a 400' loop. If you are allowing 10V then you are at 10/45 = 0.22 ohms for the loop. At 400 feet, you get 0.55 mili ohms per foot. That puts you past number 8 and into the number 6 cable.

Bob

OTRA15 · 06-04-2021, 11:46 AM

Quote:

Originally Posted by pcskier

. . .
An older thread referenced Inland Andy using one that worked great, but he didnt mention what wire size it was.

Speaking of older threads, could you please update us on how the winter went in your aluminum tent in Park City, Utah?

https://www.airforums.com/forums/f46...-a-215428.html

Thanks,

Peter

BandLAir · 06-04-2021, 12:19 PM

200 feet of 6 AWG + Ground is going to be a heck of an extension cable in terms of bulk and weight. But if that is what is needed then that is what is required.

Al and Missy · 06-04-2021, 12:37 PM

...calculations should be made for 400'. There is 400' of wire between the AC and the source.

If it were DC, the voltage would drop on the plus side and rise on the minus side resulting in the difference between the two to be less by twice the loss in a 200' run. With AC the plus and minus reverse 60 times per second, but the result is still the same.

Edit:
Uncle Bob beat me to it.

That said, an EasyStart only reduces the start current, not the run current. Still, it would be a good investment for this application and will probably be dwarfed by the bill for the wire.

uncle_bob · 06-04-2021, 01:08 PM

Quote:

Originally Posted by BandLAir

200 feet of 6 AWG + Ground is going to be a heck of an extension cable in terms of bulk and weight. But if that is what is needed then that is what is required.

Hi

Best guess is it comes in just over a half pound a foot. Maybe 110 pounds for the whole thing. Dropping back to 8/3 might get it down to the vicinity of 80 pounds.

Bob

pcskier · 06-04-2021, 01:15 PM

Thanks all. Good feedback, and I touched base with Ronnie.

This is just temporary for the summer. I do have an Easy Start so starting amps will be reduced. Power is coming from a meter base that is 20-30 feet from the power company transformer.

I'm spending the summer on some property I bought and plan to build on next year, and even though it's at 7850 feet elevation, it gets warm in the afternoon if I'm working from 'home' and also warm for the pup if I leave. So I thought it would be nice to have a few hours of AC in the afternoon.

The crazy cost of wire (I'm guessing it's higher post-Covid like everything else) is why I was looking to see what I could do economically and avoiding 6 ga wire for a temporary extension cord. My thought was I would turn off all other loads on the AC side including the converter (plenty of power from solar to keep batts charged, run tv, fans and coffee maker on inverter, etc) and JUST use AC.

While I think I could squeak by with 10/3 and have a little more wiggle room with 8/3, if I do this I'll likely bite the bullet and go with ground-burial rated 6/3 that will let me run AC with no worry. I can also use the water heater and Microwave and fridge on electric, so the extra cost is worth it overall, and as Peter noted, I'll have a handy 200 ft extension cord forever. Not that I know when I'd ever need it again. The thought just occurred to me I could probably sell it as well. But also, I think I will be able to reuse the wire later when I build a guest RV Pad and Barn. So it's all good. Just need to cough up $518.

Fungus · 06-04-2021, 01:29 PM

I have a Ting device for the house. It measures voltages and send reports to me. It sends immediate notifications of power outages.

You can measure the amperage draw with a clamp meter.

pcskier · 06-04-2021, 02:27 PM

Thanks all. I also touched base with Ronnie who of course talked sensibly.

This is just temporary for the summer. I do have an Easy Start so starting amps will be reduced. Power is coming from a meter base that is 20-30 feet from the power company transformer.

I'm spending the summer on some property I bought and plan to build on next year, and even though it's at 7850 feet elevation, it gets warm in the afternoon if I'm working from 'home' and also warm for the pup if I leave. So I thought it would be nice to have a few hours of AC in the afternoon. I wasn't expecting the need for this but this aluminum tube gets warm in the sun.

The crazy cost of wire (I'm guessing it's higher post-Covid like everything else) is why I was looking to see what I could do economically and avoid 6 ga wire. My thought was I would turn off all other loads on the AC side (plenty of power from solar to keep batts charged) and JUST use AC.

While I think I could squeak by with 10/2 and have a little more wiggle room with 8/2, if I do this I'll bite the bullet and go with ground-burial rated 6/2 to make the extension cord that will let me run AC with no worry. I can also use the water heater and Microwave and fridge on electric, so the extra cost is worth it overall, and as Peter noted, I'll have a handy 200 ft extension cord forever. Not that I'll ever need it again LOL. But also, I think I will be able to reuse the wire later when I build a guest RV Pad and Barn. So it's all good. Just need to cough up $518 for 200 feet of were

OTRA15 · 06-04-2021, 02:52 PM

A good investment, preceded by a wise decision IMO!

In terms of all of your overall investment costs, including the trailer, tow vehicle, property costs, all the various insurances, etc., this is a very minor out-of-pocket expense . . . and a good foundational building block in your country fortress! Yes you can sell the wire used, or use it in a shop/building later, perhaps in shorter lengths as needed.

coasttocoast · 06-04-2021, 07:50 PM

You can check your voltage drop with an Ideal 61-164 SureTest Circuit Analyzer. I always spend a little extra on my electrical system. Thicker wires and premium plugs will make a more secure connection.

guskmg · 06-04-2021, 08:00 PM

If you ae going to be building a house why don't you get your power company to go ahead and put in a full sevice and be done with it. Even if it is temporary you could put in a large underground propane tank and run a generator. Either, a portable or an emergency sized genny. Bulk propane is way cheaper than by the portable tank.
guskmg