what gauge for 15 amps?

[daz]

I know this isn't music related, but i didn't know where else to ask quickly. I have a friend who's in a wheelchair and in this heat he needs to be able to turn the window box air conditioner on and off without having to get up. Usually he's ok, but lately we are having a heat/humidity wave thats killing him. So i need to make a remote for him asap. I'm simply making a box to cut the mains in and out with a 20 amp rocker switch. What i need to know is what wire gauge to use for the 5 foot extra run? I don't know what his is rated but i looked online and most seem to be under 15A. Thanks

[Paleo Pete]

My sister and her boyfriend are both journeyman electricians, 30 years or more each, and they won't use any smaller than 12 in home wiring, most of it requiring up to 15 amps. Over 20 amps I think they use 10 gauge. Don't have my phone with me, (of course, just when I need it) but will call and ask later today, if different I'll correct myself tomorrow. I think 14 gauge may handle 15 amps, especially for a short run like that, but I would say stick to 12, that's what they always use for house wiring.

[Steve Conner]

Yeah, 14 gauge is the minimum but 12 would be better.
Ampacity Charts

[daz]

i have 14. Is it however ok to make the 5" junction between the unit's plug and into the wall where i plan to run the 14 ga from out of a a/c cable thats 16 ga?

[Tom Phillips]

You could consider a turnkey approach such as a wireless appliance switch module. For example ApplianceLinc Relay - INSTEON Plug-in Appliance Control Module, 3-pin - Smarthome .
This one is "Rated" at 15 A but a heavier duty version may be needed to handle an air conditioner which I'd expect to have a hefty turn on surge. Further searching should turn up some other choices.

[daz]

yeah, i looked into those but they aren't heavy duty till they are a lot $. In any case i already made this thing and i think it should be ok. I used 14 ga but it's 16 from the plug that goes into the wall to the outlet the unit plugs into, but thats maybe 4". I think it'll be good.

[eschertron]

I know this isn't music related, but i didn't know where else to ask quickly. I have a friend who's in a wheelchair and in this heat he needs to be able to turn the window box air conditioner on and off without having to get up. Usually he's ok, but lately we are having a heat/humidity wave thats killing him. So i need to make a remote for him asap. I'm simply making a box to cut the mains in and out with a 20 amp rocker switch. What i need to know is what wire gauge to use for the 5 foot extra run? I don't know what his is rated but i looked online and most seem to be under 15A. Thanks

His AC unit should have a sticker on it somewhere, or contact that manufacturer for the details. I'm a little concerned that you're using a length of 16ga. my ampacity chart doesn't go that low, but I think it's rated at no more than 10A.

Here's a story: I rented a drum sander to refinish the wood floors in my living room. I used an orange, heavy-duty extension cord I had in the house. When I stopped after running the sander for a while I discovered the extension cord had gotten hot enough to actually melt and deform. It was useless after that. Much more time running the sander and I might have melted through the insulators completely...

I'm not comfortable with the thought of building an electrical hazard and placing it in the home of someone who's wheelchair-bound. if you nee to run 16ga, then double up on the conductors. Or run the 14ga.

edit: Is there any way to interrupt the control circuit from the ON/OFF switch? that might be an easier solution when all is considered.

[daz]

I ran mabe 4-5" of 16 because i didn't have a male AC plug. I had a female tho. So i took a AC power cord that was 16 ga and ut it about 4-5" from the plug and the ground and one hot wire go to the female. Then the other hot wire from the plug comes out and is connected to the 14 ga. I guess i could cu the ires right at the very end of the plug and attach 14 ga. But i guess i better go get a plug. Problem is i can't do that till the weekend and it's getting hotter and more humid by the day. thats the only reason i used what i have. But if you think it's dangerous i'll wait on it.

His AC unit should have a sticker on it somewhere, or contact that manufacturer for the details. I'm a little concerned that you're using a length of 16ga. my ampacity chart doesn't go that low, but I think it's rated at no more than 10A.

Here's a story: I rented a drum sander to refinish the wood floors in my living room. I used an orange, heavy-duty extension cord I had in the house. When I stopped after running the sander for a while I discovered the extension cord had gotten hot enough to actually melt and deform. It was useless after that. Much more time running the sander and I might have melted through the insulators completely...

I'm not comfortable with the thought of building an electrical hazard and placing it in the home of someone who's wheelchair-bound. if you nee to run 16ga, then double up on the conductors. Or run the 14ga.

edit: Is there any way to interrupt the control circuit from the ON/OFF switch? that might be an easier solution when all is considered.

[daz]

Is there any way to interrupt the control circuit from the ON/OFF switch? that might be an easier solution when all is considered.

Not sure what u r asking.

[daz]

I asked the facilities guys if they were going to a hardware store today, and they said yes and they're gonna pick me up a plug. So i'll redo it with all 14 ga. Also, the wire is rubber jacketed so heat wont kill it as easily as plastic.

[Mark Black]

The unit on/off switch MAY be a low-voltage or at least low-current system controlling a solid state or mechanical relay within the unit to handle the larger current needed to run. Accessing that circuit MIGHT get you the ability to use smaller gauge wire and would prolong the life of your remote switch.

For the mains power feed using a short length of smaller-gauge wire effectively creates a "fusible link" which could burn up with a fault condition in the A/C unit or just with continued high current demand. I don't like it. I also don't like the use of unconventional wiring.

Use minimum of the same gauge as the A/C unit existing cord, and follow UL/NEC conventions for wiring. Even then if there is a fire it's probably going to be your fault - most of the fire inspectors I have run across will "red-tag" ANY home-built devices/wiring and demand use of commercially-built UL-listed equipment. You can't even use a "repaired" AC cord at a construction site around here - gotta be all stock with the molded ends. After all, many (if not most) of the NEC rules exist because somebody died, and UL is in the business of making sure equipment lives up to those rules.

Edit: I see while I was typing you came up with some larger gauge wire - that's better at least.

[daz]

I got the plug and when i started to redo it i noticed the blades can be pulled out. So i not only screwed them on, i soldered them while out so it wouldn't melt the plastic. So they are rock solid and all wiring is 14 ga. It very well insulated and where i sliced the wires i triple heat shrunk them and wrapped the whole thing up tight with duct tape so it's solid as a rock. I even used both sides of the 20A rocker just to be even safer there. I'll see if his cable has the gauge on it and not use it if it states a gauge bigger than 14.

[Bill Moore]

Soldering is not a good idea for high current wiring. I have done it for automotive repairs for low current devices, but on high current devices, the wire will heat, and the solder is holding nothing. A solid mechanical connection is the best!

[Steve A.]

As a retired HVAC service tech I worked on many room air conditioners. To add a wired remote I would wire in a contactor which is a heavy duty relay used for AC compressors. I would probably add a 24vac transformer so that the wiring to the remote switch would be low voltage. Or you could use a contactor with a 120vac coil and follow the rules for proper line voltage wiring.

An AC compressor usually draws several times its operating current on start-up which is why contactors are used instead of regular relays.

P.S. Another option is for your friend to buy a new window AC that has a remote control which can do a lot more things than just turning it on and off. You didn't mention if your friend is in a wheelchair temporarily in which case it might not be a good investment. Here is a 5,200 BTU room air conditioner that I found at Amazon for $155.77 with free shipping.

Amazon.com: Keystone KSTAW05A Energy Star 5,200 BTU 115-Volt Window-Mounted Air Conditioner with "Follow Me" LCD Remote Control: Home & Kitchen

Soldering is not a good idea for high current wiring. I have done it for automotive repairs for low current devices, but on high current devices, the wire will heat, and the solder is holding nothing. A solid mechanical connection is the best!

Having spent 20+ years in the field repairing air conditioner I carried a portable soldering iron so that I could solder the high-temperature uninsulated crimp terminals I used. A crimped terminal might last 5 years but I rarely saw a crimp terminal fail when I soldered it as well.

You do bring up a good point about the necessity of have a solid mechanical connection in a solder joint. And in an automobile the side-to-side and back-and-forth forces on a wire splice would make a good mechanical connection critical.

Thanks!

Steve Ahola

[daz]

Soldering is not a good idea for high current wiring. I have done it for automotive repairs for low current devices, but on high current devices, the wire will heat, and the solder is holding nothing. A solid mechanical connection is the best!

If you read my post again you'll see i didn't just solder them. I used the screw terminals and screwed them in tight, but just to make it even stronger so as not to rely totally on the screw i soldered them as well after i screwed them on.

On a side note. i found some 12 ga rubber jacketed stuff and i'm redoing it with that. i gotta think thats good enough unless his unit is much beefier than most. But i am going to look at it when i get there and see if it list the amps on it. So as it is, we have a 20A switch in which i doubled up the sides which should be a non issue, and about 5 feet of 12 ga rubber jacketed wire screwed then soldered to the terminals. Can anyone still see fault with that is his unit is ay 15A or less? Or should i just tell him we can't do this? If its still a issue i will consider Steve's idea and look for a 120v relay with heavy duty contacts. A great idea, but i fear when i go to find one it will cost a fortune, be had to find with a 12v coil, be too big or some other issue.

EDIT: nevermind what i said....the jacket is plastic. Coulda sworn it was rubber till i stripped it. And i really don't want to use anything without a very sturdy jacket. If i use a relay, what should i look for as far as the contacts besides a good solid 30A ?