Troubleshooting in a old house

[Birddawg]

Thank you. We thought this house was built around 1926, so it was against code when the house was built unless the house is older than we think it is.

 

[480sparky]

I've seen homes that are just 15 years old that were built without any permits or inspections. Just because the N in NEC stands for National doesn't mean there were permits and inspections everywhere all the time.

 

[al hildenbrand]

I still find original installs of this Carter 3 way in single family two story dwellings built and wired in the begining of the 1900s. It's always Knob & Tube. The guy who drilled in the conductor could save labor with it.

Now, one truly inspired variation of this "polarity switching 3 way" occurs when the original wiring had a branch circuit upstairs and a different branch circuit downstairs. The original Power Company service has to only be 120 Volt. The stairwell light winds up getting power from either circuit, depending upon the switching path.

Such a set up becomes an important detail when the first service upgrade to 240 / 120 Volt occurs. Those two original K & T branch circuits have to be kept on the same buss, or the 240 Volt switch position will always take out the lamp.

 

[ptonsparky]

I remember vaguely the first knob and tube ’fill in the name’ three way that messed with my mind. I spent way too much time trying to figure it out and ended running new.

 

[al hildenbrand]

It started as Rule 19.a in the 1915.

Birddawg, if you go to the 1915 Rule 19 a, you will not find the prohibition that you are thinking of. It comes, years later, when polarized cord caps and polarized lampholder installation gets written in.

 

[480sparky]

Birddawg, if you go to the 1915 Rule 19 a, you will not find the prohibition that you are thinking of. It comes, years later, when polarized cord caps and polarized lampholder installation gets written in.

The language that eventually becomes 404.2 starts out in 19.a. It changes many times.

 

[LarryFine]

Birddawg, if you go to the 1915 Rule 19 a, you will not find the prohibition that you are thinking of. It comes, years later, when polarized cord caps and polarized lampholder installation gets written in.

And having a grounded conductor.

 

[kwired]

And having a grounded conductor.

Yes, if for some reason you don't have a grounded conductor this switching method could possibly be NEC compliant may depend on other conditions of the install.

 

[hillbilly1]

I've seen homes that are just 15 years old that were built without any permits or inspections. Just because the N in NEC stands for National doesn't mean there were permits and inspections everywhere all the time.

We didn't get permits and inspections until about six years ago. Thats why I rarely do work in the county, hard to bid against romex on a commercial job!