[quickthrowman]

NM wiring is extremely common in every state (except for Illinois) and NM is allowed without restrictions in multi-family stick-built housing up to four stories. You must live in Chicago or some other restrictive AHJ.

There are still existing functional knob and tube wiring systems that are 100 years old

[Shebanator]

I still have some knob and tube wiring in my home (which is 96 years old). I've ripped out most of it over the years, but it is amazing how reliable it actually is.

[jdeibele]

Were you able to do that without digging into the walls? My house had a bathroom and the kitchen upgraded by the previous owner and we did the basement but most of the house remains on knob-and-tube.

I've gradually added GFCI outlets to each circuit. They're not grounded, unfortunately, but they do trip if something were to go wrong. And it allows us to plug in 3-prong plugs without using those horrible 2-to-3 adapters.

We had to change home insurance companies because Amica blacklisted us the instant they heard there was knob-and-tube wiring. A few other companies have the same approach. But it's not like homes are spontaneously combusting everywhere because of it.

[Shebanator]

We ripped open the walls. This was done in the context of a larger remodel and then a rebuild of the back of the house after a fire.

[ComputerGuru]

> (except for Illinois)

Guess where I am ;-)

(Not in Chicago/Cook, though.)