JohnDS
Senior Member
- Location
- Suffolk, Long Island
- Occupation
- Electrician
Just a refresh if someone can clear this up based on these numbers. I'm probably screwing it up somewhere.
Appliance 200ft away and 7amp draw on 120v
Max allowable voltage drop 3%
CMVD=2KIL
2 x 12.9 x 7a x 200' ÷ 3.6v = 10,033cm = round up to 10,400cm which is 10awg.
So why when I do it the other way, it's telling me 10awg will give more than a 3% voltage drop?
2 x 12.9 x 7a x 200' ÷ 10,400cm = 3.47%vd
When I do the same as if it was 240v it's over 5%vd respectfully.
2 x 12.9 x 7a x 200' ÷ 7.2v = 5,017cm = round up to 6530cm = 12awg
2 x 12.9 x 7a x 200' ÷ 6530cm = 5.53%vd
What did I do wrong?
Appliance 200ft away and 7amp draw on 120v
Max allowable voltage drop 3%
CMVD=2KIL
2 x 12.9 x 7a x 200' ÷ 3.6v = 10,033cm = round up to 10,400cm which is 10awg.
So why when I do it the other way, it's telling me 10awg will give more than a 3% voltage drop?
2 x 12.9 x 7a x 200' ÷ 10,400cm = 3.47%vd
When I do the same as if it was 240v it's over 5%vd respectfully.
2 x 12.9 x 7a x 200' ÷ 7.2v = 5,017cm = round up to 6530cm = 12awg
2 x 12.9 x 7a x 200' ÷ 6530cm = 5.53%vd
What did I do wrong?