Pete is absolutely right!!
I had to replace one run of live knob and tube in Dad's house last year before we sold it. I wanted to make sure all the knob and tube I saw in the basement was abandoned in place. I discovered one run of knob and tube wire was still hot!! It fed the two lights and two outlets in the sun porch, so I rewired it. Grandpa plumbed the house and got a friend to do the initial wiring way back when in the 1888 house. Then he and dad rewired back in the early '50s. I don't know how they missed that one.
