Anyone replace knob and tube wiring?

[Anonymous]

I bought a pre-1950s home last month and of course had it inspected. The home inspector completely missed the active knob and tube wiring all over which I just found trying to install a doorbell. Ironically the house has a brand new breaker box. Has anyone recently gone through the process of doing this? Did you need to move out while it was being replaced? How much of your walls did you need to replace/repair?

[Anonymous]

We tore the house down and built new

[Anonymous]

It would cost a fortune to replace it. Use a wireless doorbell.

[Anonymous]

We replaced it all in a large turn of the century house. Cost about $25k and took the electricians 3 weeks. They cut some holes in walls and ceilings (which we patched), but it wasn’t terrible or anything like having renovation/construction work done in terms of dust or disruption. We were there working at home the whole time.

If they can run wires through an unfinished attic (for upstairs) and basement (for downstairs) that helps. It was worth it for safety and convenience (grounded outlets everywhere). Get a bunch of bids. Good luck.

[Anonymous]

If it's working it doesn't have to be replaced. Just plan on dealing with it as you do other upgrades.

[Anonymous]

This is a major fire hazard. Knob and tube wiring is ungrounded. There’s a lot of it where I live and it costs $30-75K to replace depending on size of the house.

[Anonymous]

Anonymous wrote:This is a major fire hazard. Knob and tube wiring is ungrounded. There’s a lot of it where I live and it costs $30-75K to replace depending on size of the house.

Most electricians feel properly installed knob and tube is quite safe. If you don't believe me, go to a site that specializes in electrician discussion like mikeholt.com and search the archives.

If the fuse box has been upgraded to breakers, the lack of grounding can be addressed by putting in a ground fault circuit breaker.

There are a few problems you typically see with knob and tube. One is that the circuits lack sufficient capacity, both in amperage and in number of outlets. This leads to people running extension cord, which creates all sorts of hazards. Another is that it often gets added onto in unsafe way; the knob and tube itself is not unsafe but the add-ons are.

Some insurance companies won't insure houses with knob and tube, nor with fuse boxes. That can be a major problem.

[Anonymous]

Usually the cost isn't so much replacing the knob and tube, it's bringing the rest of the house up to code once you dive in.