rburkees57
New member
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- Indiana
I know what size wire to use for short runs, but at what length do you have to take in consideration distance?
Sizing Wire (Considering Run Length)
- Thread starter rburkees57
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bphgravity
Senior Member
- Location
- Florida
Re: Sizing Wire (Considering Run Length)
The length at which on branch circuits the voltage drop exceeds 3% per 210.19(A)(1)(FPN4) or 3% on only the feeder per 215.2(A)(4)(FPN2) or a total of 5% from the OCD of the feeder to the last outlet on the branch-circuit. This is not an actual requirement, but considered for efficent operation. The short way, start doing calculations when lengths start exceeding 100 feet.
The length at which on branch circuits the voltage drop exceeds 3% per 210.19(A)(1)(FPN4) or 3% on only the feeder per 215.2(A)(4)(FPN2) or a total of 5% from the OCD of the feeder to the last outlet on the branch-circuit. This is not an actual requirement, but considered for efficent operation. The short way, start doing calculations when lengths start exceeding 100 feet.
- Location
- Massachusetts
Re: Sizing Wire (Considering Run Length)
bphgravity, that is exactly what we do too, for lighting and general purpose outlets we bump up a size for every 100' from the panel this usually works out well.
On a engineered job we did, the 20 amp roof top outlets needed #4 copper. try landing that on a GFI outlet
bphgravity, that is exactly what we do too, for lighting and general purpose outlets we bump up a size for every 100' from the panel this usually works out well.
On a engineered job we did, the 20 amp roof top outlets needed #4 copper. try landing that on a GFI outlet
bryonb
Member
- Location
- Oklahoma City, OK
Re: Sizing Wire (Considering Run Length)
This rule of thumb Generally works, but lets look at a common 20 amp 120 volt branch circuit. You can only run about 55 feet at 16 amps before you have to upsize to #10. At about 90 feet you would have to run #8.
This has bit more that one electrician in the butt, myself included.
This rule of thumb Generally works, but lets look at a common 20 amp 120 volt branch circuit. You can only run about 55 feet at 16 amps before you have to upsize to #10. At about 90 feet you would have to run #8.
This has bit more that one electrician in the butt, myself included.
Re: Sizing Wire (Considering Run Length)
Try going to www.tvss.net/ go down to free tools and find the voltage drop caculator.
Try going to www.tvss.net/ go down to free tools and find the voltage drop caculator.
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