A customer is renovating a loft above a barn to basically a small house. The barn is currently fed with 1AWG copper under a 125amp breaker from the main house which is about 400 ft away if not more. I did an optional load calculation which came out to 91amps. Should I be concerned with the load under a 125amp breaker and also voltage drop? Using a calculator by cerro wire i get the following. 400ft at 50 amps = 6.2v dropped at 120 and 240. I chose 50 because of load demand.
Voltage Drop to a barn
- Thread starter HuntNJ
- Start date
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
How hard is it to increase the conductor size?
ptonsparky
Tom
- Occupation
- EC - retired
I would warn them, but not be overly concerned.
If anything, the solar should help the voltage drop. At least while it’s producing.
ptonsparky
Tom
- Occupation
- EC - retired
I know just as much as you about solar, but I would think it would help considerably or negate it entirely during the day.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
If there is enough solar, then the wire resistance can cause voltage rise. Sufficient voltage rise will cause the solar to trip out.
Your numbers don't look bad enough to be a problem, except perhaps with dimmable some LED lighting. I'm with post #3, warn but don't worry.
Your numbers don't look bad enough to be a problem, except perhaps with dimmable some LED lighting. I'm with post #3, warn but don't worry.
If the solar isn’t tripping out currently, adding loads on the solar end of the feeder isn’t going to cause it to start.
solarken
NABCEP PVIP
- Location
- Hudson, OH, USA
- Occupation
- Solar Design and Installation Professional
I think this would be unlikely. If the subpanel is fed from a 200A main panel, the inverter is probably a 7.6kW model or less, so 32A. That would not have much voltage rise on 1AWG feeder, even if no loads on in the barn. I'm also with post #3.