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Progress Report: Mission Knob and Tube


For those of you that are wondering what knob and tube wiring looks like, I snapped a few photos. Knob and tube wiring was common in the early part of the 20th century. I think the old metal boxes and glass and porcelain they used are pretty cool looking… the fraying fabric covering the wires, however, scares the crap out of me.


This is what the old wire looks like – it’s thin and covered with fabric, and the knobs hold it up on the joists. It is supposed to be secured between the two porcelain pieces, but much of it is now just draped across them. The lines run willy nilly ALL OVER THE PLACE and are very hard to make sense of. Unlike newer wire, the hot and neutral wires run seperately to fixtures; there is no ground wire.


This is an old box we took down off the wall – check out the glass, very cool looking right?! I will be happy to throw it out though.

We’ve been diligently rewiring the downstairs. The fridge is now on a GFI breaker (no death by snack attack, hooray!), and the living room, foyer and office are almost entirely rewired. We still have a lot to do, but now that we’ve gotten the hang of it each outlet goes a little bit faster. And the basement looks ten times better already.

When this is all over, we won’t have to worry about our electric for many, many years. I look forward to that.

Comments, Thoughts, and Feedback

Nick had this to say on 01.18.05:

You guys look like you’re having too much fun :)

Thanks for the wonderful blog – it and others (houseinprogress) were an inspiration for me to start my own site this past week.

Check out my latest post — it’s electrical week at our house too…

Kristin had this to say on 01.19.05:

We have some old knob and tube still hanging out in our attic … hmm, guess we should check and make sure it’s not still hooked up to anything.

It is really cool-looking stuff, though.

Alex had this to say on 01.24.05:

Electrical week all over I guess. My wife and I are restoring our 1885 Alexandria, VA row house, bit by bit, and this week we are trying to put our kitchen and surrounding areas back together now that some structural work is done. While we were uncovering the hideousness within, I decided to rip out the old wiring and run all new stuff, as well as structured wiring for voice, data, and video, and speaker wiring for whole house audio.

I decided on 4 Cat-6 lines for voice, data, and general other (like whole house audio controls) and 2 Quad Shielded RG-6 COAX for video. I likes this better than the all in one wiring for flexibility, but it sure caused a tangle.

Here is a good before of the crap I found in the water damaged and termite infested wall.

Here is a good after

Even though our knob and tube has long been replaced with the also horrible armored BX, it is still just as scary when you open the ceiling and find this (all live mind you).

One thing to consider when it comes to GFCI circuits and fridges. GFCI can trip for what is otherwise a null reason (such as lightning nearby), and this can leave you a little defrosted if you have your fridge on that outlet. So be sure to keep a close eye on the fridge. The biggest issue with refrigerators and GFCI outlets or circuits is simply a design incompatibility. GFCI is meant to expect an equal flow on the neutral line as it is sensing on the hot. In other words, it should have the same out as in, and if not, the GFCI circuit expects that it is exiting through a short (possibly a human) and shuts off. The GFCI circuit looks for roughly >5 milliamps of a difference in order to trip. Refrigerators run on motors which having windings that can basically hold onto some of the load and make the difference large enough to trip the circuit for no apparent reason. It may not happen while it is cold out and the fridge isn’t working as hard/often, so watch it when it is warm. If that happens, and that circuit has no outlets that run within 6 feet of a water source (not the fridge) I would replace the circuit.

mindy had this to say on 01.24.05:

Alex – akk, you have hideous wiring too. Don’t you wonder who it is that is so lazy, they can’t be bothered to grab a wirenut instead of electrical tape??

Thanks for the advice about the fridge – it’s right next to the sink so water is a concern. We haven’t had it trip yet, but as you mentioned it’s FREEZING in upstate ny so the fridge isn’t kicking on and off very much!

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