Voltage drop and calculation

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Davidbear

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Air compressor. Single phase 240v 17.8amps 150f run of wire run inside of a shop. What size wire and voltage drop and breaker should it be ran on?
 
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I have a guess that it trying too learn something new. 25 amp breaker number 6 wire. Seeing how other people do calculations just learning.
 
You didn't say whether this was single phase or three phase. My calculation tells me you can stay below 2% VD if you use #10 wire for a three phase system or #8 wire for a single phase system. This assumes copper wire. I agree with a 25 amp breaker.
 
Newton said:
  • Multiply current in amperes by the length of the circuit in feet to get ampere-feet. Circuit length is the distance from the point of origin to the load end of the circuit.
  • Divide by 100.
  • Multiply by proper voltage drop value in tables. Result is voltage drop.
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Our cable tables per BS7671 give as mV/A/m. The m being metres. Seems simple enough.
 
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