We have an old house (circa 1950). There is one branch circuit with old-style NM cable (rubber/black paper insulation, no grounding wire). This circuit powers plugs/lights in the kitchen.
Recently we plugged a 300W electric heater into the circuit, and the breaker tripped when somebody also ran an electric kettle plus some other appliances....no surprise there, since the load was probably over 15A.
However, today the breaker tripped when only a couple of lights were turned on. This would be a load much less than 15A. That is new!
Now I'm wondering about the integrity of the circuit itself....is it possible that running a very heavy load (even for a short time) caused some overheating of the wires, breaking down the insulation and causing a short that is now tripping the breaker?
Is there any way I can test the integrity of the circuit itself without crawling up into the attic or ripping out plaster walls? What is the best way to proceed from here?
Thanks in advance to the experts on this forum for their advice.