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Old 05-18-2017, 09:29 PM  
swimmer_spe
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Default Gauge of wire for 15 A extension cord

I want to get a 15A extension cord that will reach about 25 feet. I do not want to loose amperage over the length of cable. What gauge of wire do I need?


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Old 05-18-2017, 11:09 PM  
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You are plugging into 14 gauge but you can buy extension cords with 12.


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Old 05-19-2017, 12:58 AM  
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You are plugging into 14 gauge but you can buy extension cords with 12.
I know you loose either amperage or voltage over a wire, and I am trying to avoid that.
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Old 05-19-2017, 07:05 AM  
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voltage drop will not occur under 100 feet, so your ok to use 14AWG cord.
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Old 05-19-2017, 08:15 AM  
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There is a voltage drop whenever there is resistance. Resistance is based on the circular area of the conductor, the material in the conductor and the length of the conductor.

There are dozens of calculators on line you can use. Here is the first one that came up.

http://www.electrician2.com/calculat...r_initial.html

There will always be some drop no matter how short your cord is. But at some point it becomes significant.
For example: copper wire

#14 / 120v / 15a / 100’ = 9.4v drop
#12 / 120v / 15a / 100’ = 5.9v drop
#10 / 120v / 15a / 100’ = 3.7v drop

#14 / 120v / 15a / 50’ = 4.7v drop
#12 / 120v / 15a / 50’ = 3.0v drop
#10 / 120v / 15a / 50’ = 1.9v drop

Practically speaking a #12 is about twice the price as a #14 so you have the facts to decide what suits your needs best.

On a side note many years ago I was at a garage sale and an old guy had a homemade cord that was 200’ made out of heavy rubber coated wire #10 with a 4x4 box on the end. It weighs a ton. I asked him what he wanted for it and he said five bucks if you are going to use it and not sell it for scrap. I said I would use it quite a bit. He had it for many years and got the cable for free someplace and he wanted it to go to a good home. I’m not done with it yet but when I give up on bigger projects I figure I will sell it for 5 bucks also to the right person that comes along. I have loaned it out a dozen times and have thought about making a dolly to tote it around and wind it up on. Thing about tools is you only have to buy them once most of the time.
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Old 05-19-2017, 08:23 AM  
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I had a cord like that, we were using it on the roof of a church, wired into the breaker box, 20 ft up should be safe. They cut it where it came thru the wall, they must of brought a ladder.
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Old 05-19-2017, 10:39 AM  
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So, 12 or 10 gauge it is...
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Old 05-19-2017, 10:56 AM  
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Assuming you are going to power your whole garage thru this cord as you mentioned in another thread I would get a 50’ #12.

I doubt you will be drawing 15a very often but with lights and maybe an air compressor I could see you hitting 8-10a.
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Old 05-19-2017, 09:46 PM  
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Quote:
Originally Posted by bud16415 View Post
Assuming you are going to power your whole garage thru this cord as you mentioned in another thread I would get a 50 #12.

I doubt you will be drawing 15a very often but with lights and maybe an air compressor I could see you hitting 8-10a.
It is temp until he wire the garage.
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Old 05-21-2017, 03:47 PM  
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Quote:
Originally Posted by bud16415 View Post
Assuming you are going to power your whole garage thru this cord as you mentioned in another thread I would get a 50 #12.

I doubt you will be drawing 15a very often but with lights and maybe an air compressor I could see you hitting 8-10a.
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It is temp until he wire the garage.
That is correct, it will be temporary power for my garage.

I plan to run a couple of lights and possibly a power tool/compressor off of it, if possible. As far as I know, the outdoor plug is on it's own circuit.


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