Window AC and extension cord

[jessrice]

Until i finish the electricity, (okay, start and finish) in my shop, I need to power a window ac unit, that is in my wine barrel room from an outlet located my power pedestal, which is 65 feet away

The outlet is a standard 20 amp gfci ( i have several i run the tools from, each wiht there own 20amp breaker.

The AC unit i am buying is rated at 115v, 1380 w, and 12 amps. I don't know what the start up amps are, but instructions recommend a 20 amp breaker.

So, even though its not recommended, I am trying to figure out what gauge cord to use.

I own one 75' 12 gauge, which states its good for 15 amps at that distance, and i do run my table saw with it. I also have a 2 100 footers, I run my delta 760 dust collector with one of those.

Or I can buy a 10 gauge 100 footer from home depot, but would like to avoid the extra 100.00 since after i get done with my wiring, i never have plans on needing a cord that heavy.

When i permanently wire the outlet for the ac i will be using 12 gauge Romex, but at only 40'.

So, what do you engineering types think? 12 gauge 75' okay for 12 amps, or buy a 100' 10 gauge?

thanks

jesse

[LCHIEN]

The 10 gauge will have about 70% of the resistance per foot of the 12 gauge but in going from 75' to 100' you would have added 33% more resistance, so its a wash or maybe 3% worse. You would only get an improvement if you use a cord that's the same length and heavier wire.

The real question then is 75' of 12 ga OK at 12 amps, running. The starting current is somewhat immaterial. I think the 75' 12 ga will work OK.

[Tom Miller]

Or, you could make a temporary extension cord out of the 40' of 12ga romex you plan to use for the permanent wiring, thereby cutting the resistance roughly in half compared to the 75' cord. Or do you need the length?

Regards,
Tom

[LCHIEN]

Or, you could make a temporary extension cord out of the 40' of 12ga romex you plan to use for the permanent wiring, thereby cutting the resistance roughly in half compared to the 75' cord. Or do you need the length?

Regards,
Tom

he said the temporary power point was 65' away. 40' was the final location of the power but its not built yet.

[Tom Miller]

he said the temporary power point was 65' away.

Ahhh, missed that on my quick scan....never mind!


Regards,
Tom

[big tim]

I agree with Loring, it should be OK, you loose about 3Volt in that cord at 12 Amp.

Tim

[jessrice]

Thanks guys,

I am going to look at lowes and home depot for a 75' 10 ga, which would probably be the best, but will probably just end up using the 12 ga 75' I have.

One end of it, needs the plug replaced due the insulation/sheathing getting stretched to far, so i will trim the cord down to the 65' I need and that will help a little with the voltage drop.

I bought the AC last night form Sears (had to get a Kenmore due to the thermostat type, and the modification i need to due to it to chill down to 55 degrees), and got an email saying its ready for pickup.

So i grab the wife, who charged it online, and away we went. Go to the sears 15 minutes before they closed, and the ware house kid looked at my receipt and said he couldn't get it right now and handed back my paper.

I asked what do you mean, and he said they were way up high, and that a few pallets were in the way. I asked when it would be ready and he said a few days.

I was pi**ed by now, but decided to hold my cool. I asked for his name and left, slamming the door shut. Another worker asks what the problem is and i repeat my story and he says that they just got 15 pallets in, and they are in the way, plus they leave in 5 minutes.

Come back tomorrow. Now i explain to him that we are here now, my wife will be busy tomorrow and i need to get the this AC framed in. he tells me it not warm enough for AC, and to come back tomorrow.

I am sure when i go back today, with out my wife the same worthless sh*t is gonna tell me that I cant get it with out my wife present. I will be tracking down the manager for sure if that happens.

If this was something i could get somewhere else i would cancel, but i cant find the manufacturer of the ac unit.

Anyway, sometimes i wish the unemployment rate wasn't so low in my area, and the housing industry still not growing so that some of these worthless people couldn't get a job, and I could get someone that appreciated being employed and wanted to help. I know my theory isn't perfect, but its all i got!

If this would have been a new bandsaw or table saw, it could have gotten ugly.

Actually if this would have been ten years ago, and i wasn't married, i would have parked in front of the employee parking spots, and told them i couldn't move until a manager arrives. I bet when the manager showed up they would have gotten my ac unit down.

End of rant,

thanks for the electrical help.

jesse

[LCHIEN]

electrically you're being overly conservative,
12 ga. will be fine, cutting 10 feet off to make it shorter will save maybe 1/2 of a percent at the most, electrically insignificent compare to coming up a few feet short next time you need that cord, because this is just temporary.

As for Sears, the one near here guarantees 5 minutes pickup time. You log into a terminal when you arrive and they're supposed to respond and get you your item. I can't recall what the penalty is if they don't make it., probably a coupon for $$$ off next purchase.

[sbs]

#12 is plenty.

http://www.elec-toolbox.com/calculators/voltdrop.htm

I can't recall what the penalty is if they don't make it., probably a coupon for $$$ off next purchase.

$5 coupon, only good for in-store purchases, expires after 3-4 weeks.

I've gotten several...