said by cdru: said by bobrk:
Of course, that only works if the box is grounded somewhere, which most K&T boxes aren't.
I'd take an outlet plate off and see what's what behind it. I've replaced several switches in my house (built in '79) where the switch was never grounded, despite having a ground screw. The ground wire from the NM cable was just folded up and sat in the back of the outlet box unused.
My sister's house also had several outlet boxes where the outlets were 2 plugs, but there was a grounding wire clipped to the metal box. There was no reason that a grounded outlet couldn't have been installed.
Oh, halfassing jobs... I had something similar a couple years ago when my mom inherited my grandma's house. I went to install GFCI's and change out a couple "loose" outlets, and came to find that 90% of the 3 prong outlets were not grounded, even though every box had proper grounding wires in them (the ground was not hooked into the boxes either). Only ones with the ground hooked up to the plugs was at the end of a circuit. House was built in 1966.
So, a quick job turned into redoing every outlet and switch in the entire house, which honestly wasn't in vain since I found some aging backstabbed connections (grandma did complain of flickering but never wanted me to fix it). At least all the wire was copper!