 Mar 6, 2006
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How does it affect house wiring? I'm talking about all standard 120v US wiring using typical coper (15 amp outlet & breaker).
I see many 100ft 12 gauge extension cords claiming 15 amps, but what if house wiring is 14 gauge?
I see 200ft 10 gauge also claiming 15 amps, but again wouldn't the 14 gauge house wire be a bottleneck?
There's always going to be losses, even if the cord can handle the heat how can it still pull 15 amps from a 15 amp circuit?

I know they always say never to chain extension cords, and yet practically anybody that's used one has done it before.
How do you calculate a safe load when you do need to connect 2 extension cords? (any size/gauge/length)
In my case I need to go 150ft but only have 2x 100ft 12 gauge, it's certainly not safe to pull 15 amps anymore.
I can't seem to find any information on how to figure what a safe load would be for such a scenario.
Lots of "oh well it depends" answers, but I don't think that's true at all. It's either safe or it isn't.
There should be a safe number of amps to pull no matter what it is that's being plugged in.
Once I know the safe amp draw, then I can determine what items are safe to plug in.
If I had to just guess up a calculator I'd say something like this:
When chaining cords, use the lowest amp/ft cord and divide by total length
1 amp for each extension cord (14 amp max no matter the extension cord)
Problem is I don't know if electricity works linearly like that or if it covers edge cases well enough etc.
Probably shouldn't attempt chaining or heavy loads if you don't know what a cord is rated for.
In my case, with 2x 100ft 15 amp, my guesstimate would be:
.15 amp per foot, same cords and length, so just divide by 2.
2 "plugs" 2 amps
That would give me a total "safe" draw of 5.5 amps.
Let's say I got another cord instead that was 50ft, 15 amp rated.
.15 amp/ft still lowest, 100ft is 0.6666~ of total 150ft, 15amp x 0.6666~ = 10 amp
Still 2 "plugs", 2 amp
Here the guess would be about 8 amps safe max draw.
But would that be true if the 50ft was 14 gauge?
What if it was a cheapo cord that was 16 gauge?
Would it still be safe to pull 8 amp from a 100ft 12 gauge + 50ft 16 gauge?
Would the order in which the cords are connected matter?
I assume larger first would be best, but then house wiring is usually 14 gauge and comes first anyway.
I see many 100ft 12 gauge extension cords claiming 15 amps, but what if house wiring is 14 gauge?
I see 200ft 10 gauge also claiming 15 amps, but again wouldn't the 14 gauge house wire be a bottleneck?
There's always going to be losses, even if the cord can handle the heat how can it still pull 15 amps from a 15 amp circuit?

I know they always say never to chain extension cords, and yet practically anybody that's used one has done it before.
How do you calculate a safe load when you do need to connect 2 extension cords? (any size/gauge/length)
In my case I need to go 150ft but only have 2x 100ft 12 gauge, it's certainly not safe to pull 15 amps anymore.
I can't seem to find any information on how to figure what a safe load would be for such a scenario.
Lots of "oh well it depends" answers, but I don't think that's true at all. It's either safe or it isn't.
There should be a safe number of amps to pull no matter what it is that's being plugged in.
Once I know the safe amp draw, then I can determine what items are safe to plug in.
If I had to just guess up a calculator I'd say something like this:
When chaining cords, use the lowest amp/ft cord and divide by total length
1 amp for each extension cord (14 amp max no matter the extension cord)
Problem is I don't know if electricity works linearly like that or if it covers edge cases well enough etc.
Probably shouldn't attempt chaining or heavy loads if you don't know what a cord is rated for.
In my case, with 2x 100ft 15 amp, my guesstimate would be:
.15 amp per foot, same cords and length, so just divide by 2.
2 "plugs" 2 amps
That would give me a total "safe" draw of 5.5 amps.
Let's say I got another cord instead that was 50ft, 15 amp rated.
.15 amp/ft still lowest, 100ft is 0.6666~ of total 150ft, 15amp x 0.6666~ = 10 amp
Still 2 "plugs", 2 amp
Here the guess would be about 8 amps safe max draw.
But would that be true if the 50ft was 14 gauge?
What if it was a cheapo cord that was 16 gauge?
Would it still be safe to pull 8 amp from a 100ft 12 gauge + 50ft 16 gauge?
Would the order in which the cords are connected matter?
I assume larger first would be best, but then house wiring is usually 14 gauge and comes first anyway.