We are looking at an old house to buy (1930's?) that has some knob and tube style wiring. Is this type of wiring safe, is it allowed by code? We are most likely going to rent the house to tenants. Should we worry about the old wiring?
Kerry - Portland, ME
Knob and tube wiring is still found in many old houses, and although it is very outdated, if it is not damaged or frayed it can usually be considered safe. Yet keep in mind that any kind of electrical wiring is safe, until it's not. It's nearly impossible to fully inspect all the wiring in an old house, so at some point you are taking a chance when you choose not to replace and update old wiring.
Obviously, you should hire a licensed electrician to inspect the home's wiring and offer a professional opinion as to the condition of the knob and tube, as well as other safety and code issues. An electrician can also determine what size electrical service currently feeds the home. If the wiring has never been updated, then chances are this house might only have a 60 amp or 100 amp service panel, which could be inadequate by today's standards.
In my opinion, I would allow room in your remodeling budget for a new 200 amp service panel and some updated wiring. This is a solid investment in safety, not to mention that it is going to need to get done eventually. New wiring, which can safely handle the increased electrical loads of modern life, could also be a real selling point to your future tenants. Plus, you may just sleep easier knowing that you went the extra mile to be a responsible landlord and thorough remodeler.