Found out the hard way that a standard 15 amp breaker can handle a 2000 watt space heater, but only if it's the only thing on the circuit

I was helping my buddy rewire his garage in Akron last month, and he had this old space heater he wanted to plug in. I told him it was fine, but then I got curious and looked up the actual math. A 2000 watt heater pulls about 16.6 amps, which is over the 15 amp rating. The breaker might not trip right away, but it's running hot. I found this on a forum post from an inspector, and it made me pause. I mean, I've seen those heaters on 15 amp circuits before and never thought twice. It's one of those things you assume is okay until you actually check. Makes you wonder how many houses are running like that without issue. Has anyone else had a call for a tripping breaker that turned out to be just a heater and a few lights on the same line?

2 comments

2 Comments

theagibson14h ago

Yeah that math is sneaky. Had to run a dedicated 20 amp line for my garage heater.

lily7013h agoMost Upvoted

Actually @theagibson, a 20 amp line is the bare minimum for a garage heater. Most units need a 30 amp circuit to run safely without tripping the breaker. It's a super common mix-up with the wiring.