Lighting transformer in attic question??? (2024)

I would say it depends on the manufacturer instructions and the listing of the transformer. Also make sure your wire is rated for it's use. Most low voltage cable isn't rated for concelled spaces (ie. fished in or through walls). Seagull makes wire that is rated and has been the only one I have found so far.

What about good old NM cable? IMO the attic shouldn't be a problem unless the manufacturer feels that the excessive heat might shorten the life of the transformer.

I used those Qtrans before. They called them at the time the "Cadillac" of low voltage lighting transformers. All these fancy shmancy yolks and filters designed for dimming. I put them in a attic but because of the loads that they served I had to use Romex to feed the low voltage track. The thing about low voltage lighting is that if you have multiple feeds for the lights from the same transformer then all the cables have to be the same length otherwise you'll get some lamps that are brighter than others, at long distances.

Couldn't find the listing other than "For installation in raceways, trays, wireways, troughs, channels, ducts & conduit; direct burial"

We do this from time to time. I always use 10-2 NM and locate the transformer where it is easy to inspect if you need to. Also they have a "breaker" reset on them that you will want to access without a crawl if it trips. We had a cable light that the tapers hit both conductors with a trawl while the lights were on "pop". I was very glad I put the transformer where I could get to it without a fight. Make sure all the connections are tight LV lighting doesnt like loose fittings.

Depending on the distance with a 300 watt load youmay need a #8 wire. I have done that more than once and I almost never use #12 esp. for 300 watt load.