I'm trying to troubleshoot an issue that's been happening with one of our circuits in our '87 house (home office). At least twice now, the 15 A circuit breaker has been tripped on our 200 A breaker. Here are the details and steps I've taken to troubleshoot:
- Load sources in home office: Work desk with laptop, external monitor, overhead light fixture, 500W electric space heater on desk, laptop charger (Note: I believe the bathroom next door is also part of this circuit, and it has 1 GFCI outlet and vanity lights overhead).
- My wife has said that her laptop/desk space heater all turn off first, followed by the overhead lights a short while later (not all at once). This usually happens after the space heater has been on for about an hour.
- Replaced the outlets in the room (needed anyways, a lot of them couldn't hold prongs in anymore)
- Plugged in a kill a watt to determine total system wattage draw. With the whole desk going, as well as the space heater, total known system load is around 600W.
From what I understand, because this is a 15 A circuit, we should be able to draw around 1800W of power before anything trips. My reading of 600W is well below this limit, yet it seems that after a short while the circuit still heats up enough to trip the breaker.
Any idea what could be happening? Is this an indication of a faulty fuse in the circuit breaker? Is there a phantom load somewhere that is pushing us past the 1800W "limit" (1200W though??)
Thanks in advance!
Edit: for clarity, the 15 A circuit breaker is tripping, not the entire 200A circuit breaker. The 15A circuit breaker has a TEST button in it as well.
Edit 2: pictures of the circuit breaker - number 14 is the one in question.
Edit 3: upon testing the affected circuit breaker (number 14) it immediately tripped, which seems to indicate a fault to ground issue.