Ever wonder about the weird threads on light fittings?

[BC38]

...Knob and tube appears dangerous but it isn't necessarily so. My ex and I had a 1940 house with knob and tube. The neighbor was a fire fighter and explained knob and tube is quite safe if it's in good condition and not abused or used as a clothesline....

...and there is the "rub".
Most W&T installations are getting close to 100 years old, so how many of those installations are still in "good" condition? The woven-asbestos cloth insulation that existed when the wiring was originally installed has experienced 100 years of deterioration. If it isn't exposed, it may not be all that dangerous, but I sure wouldn't want to trust it. Especially since, in most cases, at least some of it is exposed.
There are a lot of good reasons that it was phased out and replaced by modern wiring several decades ago.
It's like having a 110v AC electric fence installed in the walls of your home.
No thanks.

 

[WR Moore]

My parents house was apparently finished in 1941- from newspapers about Pearl Harbor found under linoleum. I found that cloth insulated wiring in one outlet that my parents had decided had been killed by a lightning strike. When I learned enough about electricity, I decided that was nonsense and pulled the outlet apart. IIRC, I just left that outlet alone after finding the wiring was dead and installed a new receptacle and modern wiring to it. FWIW, the code back then required 1 switch operated light and one receptacle per room, there could be more. The entrance panel was 50 amps and, as Krogen noted, 2 wires everywhere in original wiring.

Generally, the wires running alongside the roads-at least in rural areas where you see transformers on the service to each house-run at 14.4KV. I expect they can go higher. IIRC, safe distance from 14.4K is about 10 feet if you're grounded.

 

[desi2358]

LOL, have you ever seen an early 20th-century structure with "knob & tube" wiring?
When I was working as a service manager for an electrical contractor I saw several of them.
Knob & tube was a wiring system of copper wires, with minimal (cloth) insulation, strung from one stud-mounted ceramic insulator to another, behind the lath & plaster walls of the structure.
In the early days of "electrification" of our country, knob & tube wiring was the standard, because it was the best technology available at the time.
By today's NEC standards, knob & tube wiring is basically an electrical fire just waiting to happen. But there are still quite a few old turn-of-the (last) century buildings out there that are wired that way.
Scary, but true....

Our house still had this type of wiring when we bought it back in 1992. The only new wiring was in the kitchen which had been updated at some time. First thing we did after closing on the house was get with an electrician I knew and rewired the entire house. Still have a number of the old insulators visible on the basement ceiling, just cut the old wires off and left them.

 

[mtgianni]

LOL, have you ever seen an early 20th-century structure with "knob & tube" wiring?
When I was working as a service manager for an electrical contractor I saw several of them.
Knob & tube was a wiring system of copper wires, with minimal (cloth) insulation, strung from one stud-mounted ceramic insulator to another, behind the lath & plaster walls of the structure.
In the early days of "electrification" of our country, knob & tube wiring was the standard, because it was the best technology available at the time.
By today's NEC standards, knob & tube wiring is basically an electrical fire just waiting to happen. But there are still quite a few old turn-of-the (last) century buildings out there that are wired that way.
Scary, but true....

Dad explained to me that knob and tube splices were soldered and then wrapped with tape. They were then followed up with "rubber tape" to make them water resistant. Scotch 3M electrical tape was really a wonder.

 

[SMSgt]

Now I am going to spend the rest of my day wondering what kind of weird threads are on heavy fittings.