1 - 7 of 7 Posts

#### baseballbuzz

· Registered
Joined
·
35 Posts
Discussion Starter · ·
I have used at least 5 voltage drop calculators that I found online and have come up with different numbers.

What would you calculate the voltage drop / percentage for the following 2 scenarios?

4 outlets with the farthest 310 ft away.
20 amp breaker
THHN 10 GA

Same thing with THHN 8 GA

#### mm11

· JW
Joined
·
428 Posts

15.4 volts using a #10 Cu= 12.8%
9.6 volts using a #8 Cu= 8%

NEC recommends that voltage drop on branch circuits not exceed 3%.

#### joecaption

· Registered
Joined
·
37,499 Posts
What is it your really trying to do?
Run power to an out building?
Good luck trying to connect a #10 wire to an outlet.

#### Oso954

· Registered
Joined
·
11,194 Posts

Most of the loads that you plug in are going to be 10 amps or less.

I don't usually leave things plugged into my yard receptacles. They are there so I can plug in one item when needed.

10 amps @ 310ft on #8, you are looking at about 4.8v drop or 4%. That right in line with the older 5% recommendation.

It will be less in the closer receptacles.

Unless you have a large known load out there or expect other people to be plugging in heavy loads and using them simultaneously with your use, I would be satisfied with it.

#### Speedy Petey

Joined
·
7,829 Posts
I have used at least 5 voltage drop calculators that I found online and have come up with different numbers.

What would you calculate the voltage drop / percentage for the following 2 scenarios?

4 outlets with the farthest 310 ft away.
20 amp breaker
THHN 10 GA

Same thing with THHN 8 GA
You cannot calculate voltage drop without knowing the load (amperage).
You can reverse calculate it for what the maximum load could be.
Remember, countering voltage drop is a suggestion, NOT a code requirement.

gregzoll

#### baseballbuzz

· Registered
Joined
·
35 Posts
Discussion Starter · ·
Putting in 20A breakers/outlets. May have a low voltage lighting transformer that stays plugged in at one outlet but other than that nothing except the occasional use.

#### Oso954

· Registered
Joined
·
11,194 Posts
Unless you have some device that actually has a 20amp male plug on it, there is no need for 20 amp receptacles in the US.

15 amp receptacles are rated for 20 amp pass thru.

1 - 7 of 7 Posts