I have a bid I'm working on for a customer that's building a big shed. I originally sized the conductors at 250MCM aluminum because the conductors were going to be about 400 feet long. Now, he says it's ok to put the panel on the other end of the shed, so the total length would be around 300 feet. It's a 200 amp service, but most likely the load would probably never exceed 100 amps. Mostly lighting. 20-6 lamp flourescents, an air compressor occasionally, a welder occasionally, etc.
Here's my question. If I use the 3% voltage drop for 120 volts, I can have a drop of 3.6 volts, so that would put the acceptable voltage at 116.4 volts. Ok....so his true voltage is around 124 volts. Do I use the 116.4 volts as the threshold? I would think so, because it's the acceptable level. When I do my calculation for conductor size, can I use 7.4 volts instead of 3.6 volts.
Here's my question. If I use the 3% voltage drop for 120 volts, I can have a drop of 3.6 volts, so that would put the acceptable voltage at 116.4 volts. Ok....so his true voltage is around 124 volts. Do I use the 116.4 volts as the threshold? I would think so, because it's the acceptable level. When I do my calculation for conductor size, can I use 7.4 volts instead of 3.6 volts.
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