Knob and Tube wiring

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masterintraining

Member
I was doing some research on knob and tube wireing and found the enclosed article. Thought you might like this. Don't know if it is any relation to you or not.
Question, do you know how the three-way switches function in a knob and tube set-up? I am trying to figure it out due to a friend of mine having his house with this in it. It is totally different than what I know. Can you help? I was looking for some old wiring schematics/plans and cannot get my hands on any with the layout of this kind of system. I would like to understand it better and not just cut it out of there. Is this possible? I would like to make the three-way switch work properly. The switch upstairs turns off the light and also the ability of the switch downstairs not to work. When you operate the switch downstairs, only one lead on the upstairs switch is powered, then when you flip the switch upstairs, all three leads detect becoming live. Wow, this is crazy.

Thanks for your help.

I removed the e-mail address. Please use the PM system to exchange personal information and e-mail addresses. To use the Private Mail system, click on the :D

Thanks,
Charlie

[ July 13, 2005, 10:02 PM: Message edited by: charlie ]
 
al hildenbrand

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: Knob and Tube wiring

I can't quite make out the nature of your comment and/or question.

In your first sentence you refer to the "enclosed article". Is the enclosed article the next couple sentences beginning with "Question" and ending with "Wow, this is crazy."?

Or is that article cut and pasted from somewhere else?

Or is this an actual installation that you are figuring out?

K&T 3ways come in a couple interesting variations from the way we are taught in the 21st century.

To begin with, it sounds like the switch(es) aren't in right.

I recommend disconnecting both switches, take the bulb out of the fixture, and, at the switches only find the hot or hots and the neutral or neutrals (if there are neutrals, there may not be) while the circuit is energized. Then kill the circuit and do continuity checks until you find which end is connected to which end. You'll have to do continuity checks between the switches and from each switch to the light.

Draw out the conductors and let us know what you find.
 
M

masterintraining

Member
Re: Knob and Tube wiring

Sorry for the confusion.
I originally wrote a note to Mike and just cut and pasted the letter. Though, I did try to delete the first part. Still learning how to use this kind of forum.
As far as the figuring out of the 3-way k&t switches, will do that as you suggested, thanks.
Will keep you up-to-date.
 
al hildenbrand

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: Knob and Tube wiring

One of the common K&T variations will have the polarity of the light reversing depending upon the switch positions. At the light fixture, one wire will go to the common on one threeway, and the other wire from the light fixture will go to the common terminal of the other threeway.

In both threeways, the traveller terminals are connected to a hot and neutral. . .check out Coleman Electical Graphics and scroll down to Chicago Threeway for a circuit diagram.

However, to be clear, this may not be what you have. The only way you can be sure is to map the wires first. . .continuity check or something like it.
 
B

benaround

Senior Member
Location
Arizona
Re: Knob and Tube wiring

Gentlemen,

The most common K&T three way that I have run into is as follows,

Feed 110vac to the travelers of both three way switches, now from both switches run one wire from each to the fixture, OK flip a switch,light goes On (that means a hot and a neutral of some type of configuration is present) flip switch agian or flip the other switch and it goes OFF(either hot/hot or neutral/neutral) is now at the light. Keep fliping the switches and the configuration will keep changing ,but will always work.

I was pretty new to the trade the first time I had to troubleshoot one of these, Talk about a long day,I was pulling my hair out trying to figure it out,Well the next day I finally got it, How do you charge for the service call?

frank
 
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