Common sense does sometimes prevail.
As I mentioned in the other thread, if an HVAC contractor submitted a permit application for a panel upgrade, plan check would reject it.
The “incidental” rule is to keep from things getting completely ridiculous, like I hear it is in other states.
I have a GC buddy in Texas, and if he is doing a bathroom remodel, and needs to move a receptacle over 12”, he must call an electrician. If he wants to replace the angle stop on a toilet, he has to call a plumber.
That is why California allows trades people to perform tasks incidental to their work. An electrician can patch a hole in a wall without having to call a drywall contractor, for example.
