knob and tube

[glene77is]

Now that's a new one on me. Were they solid, the kind that the conductor is tied to or wrapped around; or were they the more common two piece that pinches the conductor?

Al,
The K&T I've worked with here has mostly white knobs.
(1) Singles in the attic
(with a telegraph style wrap to secure it from 'pulling' out)
(2) Splits coming down the studs
(to clamp the single wires).
(3) Loom passing a single wire into a switch box.

 

[glene77is]

The conductors I see commonly used on K&T systems were marked white for the neutral conductor at one time but the coloring has long worn off, making it difficult to tell one conductor from the other.
... some of them sure look smaller than 14 AWG to me.

Marky,
The color deteriorates, especially from the heat in the attic.
I've measured the conductors at AWG 14,
but standards may not have been so tight back then.
I've also pulled up on 9 foot drop down a wall,
stretched out 5 inches longer!
Soft drawn copper is not used nowadays, only hard drawn copper,
and I've read that consistent thickness under tension is one reason.

( from old K4KKQ, 1958, when Ham radio was the 'real thing'). :smile:

 

[glene77is]

Most of the K&T houses I've experienced ...

>> It IS an experience, that you can learn to appreciate.

You'd typically find such a house supplied by a 30a 120v service, with both conductors fused regardless of whether one was grounded.

>> My grand-daddy's house was done this way in 1937, with a single light
>> socket in each room.
>> He tied two strings to the pully-chain, stretched to each doorway.

Receptacles were rarely installed in these first retro-wired houses,
The lights were pull-chain pendant sockets at first. One of the first home devices sold was the screw-in socket taps, sometimes with and sometimes without its own pullchain.

>> When grand-daddy bought his first radio, he put a screw-in
>> light-socket & receptical, and ran an extension cord to the radio.
>> Us little kids would lay on the floor and watch the light bulb,
>> and listen to the radio.

Thanks for the memories. :smile:

 

[glene77is]

a house im working at has white knob and tube. the house was built in 1900 and im wondering if this is wiring from 1900 as well? most 1930s knob and tube is black

EP,
My method for joining into a K&T system is :
(1) refrain from bending the old wires, as the insulation cracks off easy.
(2) slide a plastic JB onto the clipped end, mount the JB to the rafter.
(3) clean the old copper, and butt splice/Wire-nut onto it.
(4) strap the Romex going out at the required 12".
(5) If you are dealing with a corroding telegraph wrap,
then you may have to clip the wires and make several JB connections.

Some one said they had three wires coming up a wall.
There was no requirement back then that we carry a neutral with/along-side of the hot.

They also said the wires looked the same color.
Which makes finding the 'hot' wire a real problem.

Using a volt-meter to ground will not work, as there is no ground reference.
Anyway, the leakage through the deteriorating insulation, across the carbon soot covered joists will make both the hot and neutral carry a phantom voltage.

:smile:
I have resorted to a simple Neon Bulb testor with a 1 MegOhm resistor in series, using only one wire to contact the conductor, and holding the other in my hand to introduce the electric field to the testor. This method has worked many times over to determine which of the two similiarly colored conductors was the hot and which was the neutral. One caused a bright glow and the other a much dimmer glow.
:smile:

 

[al hildenbrand]

Like this?

Yup. Exactly the device that was under the 3-gang. :smile:

 

[LarryFine]

The other circuit went to a three gang wall case in the kitchen. The first gang had a single pole snap switch that controlled the pilot light in the second gang (a 4-7 Watt Xmas tree bulb behind an inch diameter lens) and the third gang which was an Edison screw shell. Sometimes there was a hinged cover on the screw shell and always there was a screw in adapter for a two wire receptacle.

" . . . and home automation was born."

 

[al hildenbrand]

" . . . and home automation was born."

:smile:

It really is hard to imagine how large that quantum step was. . . . The whys of that 3-gang switch / pilot / receptacle eluded me for a long time, until I had enough hands-on experience with the installed K&T, had seen enough different dwellings to see the patterns across economic social strata, and had read Man Out Of Time by Margaret Cheney (a biography of Nicola Tesla).

Up until electric resistance heat coils in something as simple as a clothes iron or a "toaster", the way to accomplish such simple tasks generally involved igniting the fuel fired cooking stove, and, in warmer times of the year, overheating the kitchen. One could walk into the hot room and be "warned" that hot surfaces were about simply by the air temperature change from the rest of the house.

Now, with modern smokeless electricity, the kitchen could easily still have a chill in it, yet an iron, that still looked like a sad iron one would heat on a hot stove, without any indicator light, would be hot. And without the wall 3-gang switch / pilot / outlet, there was no visual "caution" to indicate that this modern kitchen was any different than kitchens of the 1800s.

 

[K8MHZ]

( from old K4KKQ, 1958, when Ham radio was the 'real thing').

:grin:

I'm doing the best I can, OM. My kid passed her Code test when she was 11. An IBEW Journeyman friend of mine built a beautiful spark rig and is giving it to our club. Our club has QSL cards back to 1922 that me and the kid are sorting out.

Where I live the houses are full of K&T. I, too, have tossed myriads of it into the trash. No more though. A year or two ago a carpenter friend of mine told me of the value. I really don't want to get into the used knob and tube business so I just give the stuff to him.

The tubes can be used to sharpen knives fairly well, too.

 

[charlie]

. . . Soft drawn copper is not used nowadays, only hard drawn copper, . .

Actually, hard drawn copper is very hard to bend and is not used in building wiring. We use it for pole to pole wiring because of its tensile strength. :smile: