Trying to determine if I have a hazard I need to resolve...
I recently moved into a home where previous home owner did lots of dumb stuff. One thing I found was that in order to get more stuff wired to a generator transfer switch with limited breaker spots, he disconnected one line from the breaker and then inside the home bridged the two runs so those previously separated runs would draw off the same breaker on the transfer switch. Of course, his 15amp breaker there probably kept tripping as he had half the first floor now wired to it and so he dropped in a 20 amp breaker for that massive 14 gauge run. Ug.
I noticed the problem and have put a 15 amp breaker back in place... but not until we had tripped the 20amp breaker at least once ourselves. He surely had done the same many times before as he had 12amps worth of just incandescent canned lighting on there that I replaced with LED and still managed to trip with regular load on the other 20+ outlets on the combined run.
I also know exactly where he did the bridge and will be re-splitting the overloaded run. While I believe I have now achieved proper pairings to code (15amp breaker for 14 gauge runs), I’m wondering if I should be concerned about any damage caused to the lines during the period of over-ampped usage.
I did have one issue with a single can fixture that was on its own spur off that run that wasn’t consistently getting power on the supply line to the switch. I disconnected that single supply line from the outlet it branches from and rewired that single light switch to a different nearby run (that outlet was working just fine even while there were supply issues to the switch so I feel I’ve isolated and mitigated that issue). It seems unlikely to be related to the overloading issue given it would have only ever had 75-100 watts max load on it. It seems more likely that any damage of overloading nature would be closer to the root of the branching run where the load would have actually been 20amps. But I’ve not noticed any other supply issues and I can’t reasonable inspect the cables as it’s all behind finished wall.
My question - if I’m not experiencing any other issues, is there any more to be done? What is the likelihood I have any sort of fire hazard in the walls from previous overloading? Aside from very costly rewiring of that entire run, is there anything I can/should do to reduce risk of fire? Was wondering if using an arc-fault breaker would do anything? What do others suggest?