flashlight
Senior Member
- Location
- NY, NY
- Occupation
- Electrician, semi-retired
We are installing 6 low voltage light fixtures in a courtyard space. The nearest is 25 feet from the transformer, the farthest is 75 feet. When I did the voltage drop calculation, I used the full load and the farthest distance, which I felt gave an overkill factor for safety.
However, we don't usually have such a large spread between fixtures. Calculating it this way, with 300W total load and 150 feet total distance, with #8 wire at 24 volts, I get a voltage drop of 6.25 %. With #10 I get 9.77 %. But the actual voltage drops are going to be smaller, since the entire load is not at the end of the run.
What is the accurate way to calculate this ? The conduit (existing) is 1/2-in. aluminum, so there will not be room for separate pairs of conductors to each fixture.
However, we don't usually have such a large spread between fixtures. Calculating it this way, with 300W total load and 150 feet total distance, with #8 wire at 24 volts, I get a voltage drop of 6.25 %. With #10 I get 9.77 %. But the actual voltage drops are going to be smaller, since the entire load is not at the end of the run.
What is the accurate way to calculate this ? The conduit (existing) is 1/2-in. aluminum, so there will not be room for separate pairs of conductors to each fixture.
