Last night I decided to scope out the feasibility of replacing a double gang switch in my garage. I took the old switches out and found the wiring inside in this condition. Having found that, I then figured I basically couldn't leave things in that condition. 

I showed a friend as well as a colleague and both asked if something had been chewing on the wiring. I don't *think* so based on:

  
1. The box is pretty tight for space
2. I don't see any rodent droppings (anywhere on the property actually, in the box or otherwise) and I haven't in the entire time I've lived here. There was an ant infestation(a couple actually, or maybe just one - hard to say) when we moved in back in 2021. I put some Taro liquid baits down and they completely disappeared. They came back (in much smaller numbers) about a year ago so I put down more liquid baits and that's the last I've seen of then ants since.
3. I haven't seen any termites or anything like that (no frass round door frames etc.) and any time I've put screws(even lag bolts in some cases) in the wall, things haven't crumbled (other than usual drywall crumbling) 
4. The person who built my house is/was a shitty builder. These units (townhouse condo) are known for having corners cut by crappy contractors when they were built. So the electrican somehow doing that at rough in and then deciding to just let it ride isn't off the cards.


But it has got me wondering(this is the second one I've found like this - the other one was in my dining room). Could this be rodent damage, or could it just be shitty contractor when the place was built in '03?

Damage to wires in electrical box