Help figuring out voltage drop

[olytdi]

I'm trying to figure out voltage drop for lighting wiring (two banks of LEDs, each bank is 650W / 5.4 amp). Distance to switches from the panel is 60 ft. Distance to the last fixture in each bank from its respective switch is 50 ft for one bank and 70 ft for the other. I was hoping to feed both banks with one feed from the panel.

When I calculate for voltage drop, how are these lengths calculated? In other words, is one bank calculated at 110 ft (60ft plus 50 ft) and the other branch at 130 ft (60 ft plus 70 ft)? Do I calculate each branch independently with their respective 5.4 amp draw or combine them and use the longest length (130 ft)?

I was going to feed both switches with a single 12/2 feed then wire with 14/2 from each switch to its respective bank (using a 15 amp breaker at the panel, of course) but not sure that's possible with these distances due to voltage drop.

Heck, I'm not even sure that I can accommodate voltage drop even with 12/2 used throughout. Any guidance appreciated!

Thanks up front!

 

[rooster59]

You could try here-

https://www.southwire.com/calculator-vdrop

 

[mike93lx]

12/2 on each is more than enough. Run the wire and don't spend any more time worrying about it.

 

[olytdi]

Okay. I was concerned in that at those lengths and that draw, the voltage drop was approaching 5% since I would be using a single 12/2 feed that splits after 60 ft for two branch circuits totaling 11 amps at those distances.

 

[olytdi]

You could try here-

https://www.southwire.com/calculator-vdrop

Thanks you! I was using that -- the question really is how to calculate the distances on a circuit with a single feed to two branches.

 

[mike93lx]

The southwire calc at least used to be bad. Maybe they fixed it but I would trust it.

Look at the voltage range of the leds. I bet they will be fine. It's a different story when you are running stuff like motors that have startup draws which draw the power down further.

 

[olytdi]

Thanks Mike, I did consult the spec sheet and all it says about voltage is 120 - 277 Volt. I would have to think that up to a 5% voltage drop would be acceptable in nearly any device.