I have spent time charting out all the lights, outlets, etc. in our house and what breaker they are each on.

I know that most of the original part of our house in knob and tube and the early 90's addition is romex. Looking at my list I can see that a few breakers are most likely mixed, part K&T and part romex.

I believe each fixture/outlet could be:

  • Knob and tube from the outlet all the way back to the breaker box.
  • Knob and tube at the outlet, but changing to romex somewhere before the breaker.
  • Romex from the outlet all the way back to the breaker box.
  • Romex at the outlet, but changing to knob and tube somewhere before the breaker.

I could take off the outlet covers/lights to determine the first part visaully though that will be time consuming. Could I also use an outlet tester to determine if there a ground, with no ground meaning K&T at some point and a ground meaning Romex the whole way back to the breaker? Then do for each on the breaker to figure out what part is first/second?

enter image description here

  • If you can definitively separate the neutrals, then put AFCI+GFCI on all of it, and sleep well. Thanks to AFCI you no longer have to tear it all out and replace it to remove worry of fire. Commented Jun 9, 2017 at 16:10

1 Answer 1


K&T could be at any point in the run, the circuit could start romex, then switch over to K&T and then switch back over to romex (potentially with a ground pulled from another circuit).

The only way to be completely sure no K&T wiring is in use is to find and trace all of the circuits and visually make sure.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.