Noticed an old cloth wire coming down the brick wall feeding an outlet on the opposite side of our oil burner is all fray. Was going to replace it with MC but the plumber that was here doing work (why I was back there to take notice of it) mentioned there is some new local rule that they aren't supposed to be using MC around the boilers because the armor conducts the heat and cooks the wires inside. This didn't make much sense to me. I thought NM and MC are both rated to like 90C. Wouldn't they both cook around the same temp? I googled but found no mention of such a rule. I'm located in Nassau County NY.