voltage drop question, residential

[Stevenfyeager]

Most of my jobs requiring wire sizing due to voltage drop are a single cable going to a single load, such as a distant sub panel. My workers asked me about a lighting branch circuit in a very large house. Should we add all the lengths of NM cables on that circuit and if it totals say 150 - 200' or more, do we need to calculate the voltage drop like we do for single runs ? The lighting load is spread out, not like at the very end of a single run. Any advice ? Thank you.

 

[LarryFine]

For a rough idea, use half of the total circuit length.

If there's a lot of these, install a sub-panel.

 

[menoknow]

You have to treat each branch individually and do the voltage drop calc for it. Depending how it's wired I would probably just upsize the home run. You're just trying to find how much resistance is between the source and the load.

 

[Stevenfyeager]

Thank you.