Why does nobody talk about the voltage drop on long runs for outdoor lighting?

I was wiring some landscape lights at a house in Scottsdale last week, and the run from the transformer to the last fixture was about 85 feet. The owner complained the last two lights were super dim. I checked the math and realized I should've used 10 gauge wire instead of 12 for that distance. What's your go-to method for calculating wire size on long low-voltage runs?

3 comments

3 Comments

the_amy2mo ago

Honestly I used to just guess based on the run length. Now I actually use an online voltage drop calculator before every job.

amy9742mo ago

My old method was the 10% rule for anything over 50 feet. Wired a shed last year and the lights were dim, calculator showed I needed to go up two wire sizes. Felt like an idiot for not checking first.

logan_ellis2mo ago

Been there, felt that exact same way!