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chrissmith_gw

Old house - Unusual 3-way wiring problem

chrissmith
13 years ago

Looking at a duplex house, 2up/2down, built 1910, armored cable. Stuff is so old, it's often hard to see what the wire colors are. Of course, no wire nuts - just black cloth electrical tape.

Trying to figure why roof light is not lighting. It's controlled by two switches. Couldn't make sense of them, so I buzzed them out. Found very non-standard 3-way switch setup: Look at item below in fixed font:

One roof light wire connected to COMMON on first switch (on 3rd fl).

Travelers on first switch are HOT and NEUTRAL. (YES!!)

Other roof light wire connected to COMMON on second switch (4th fl).

Travelers on second switch are HOT AND NEUTRAL (YES!!!)

It appears that the HOT & NEUTRAL from the first switch go to the second switch in the same 3-conductor cable: (Use fixed font to display) (The HOT & NEUTRAL in the second switch go elsewhere, so I presume it's powering another light or outlet.)

Both switches are on the same circuit.

Now, this would probably work since you would have the combinations of H/H, H/N, N/H and N/N. Two would turn on the light and two wouldn't. Of course, you'd also have the potential for having H/H at the light!

Other nightmare is if the switch briefly shorted out the two travelers while switching. Ouch.

1. Have anyone ever seen anything like this? It's been here forever. Switches seem to work, but they're old and I was intending to replace them. Just nervous about this whole arrangement.

2. Was this acceptable 80 years ago?

3. Should I keep it, or turn get rid of 1 switch?

See diagram (you'll have to cut/paste it & view with fixed font. you can also change the back-tics to spaces):

H`--+------------------+```````````````

````:``````````````````:```````````````

````:`````````````+---`:`----------->`L

````:`````````````:````:```````````````

````:```#######```:````:```#######`````

````+---#```C`#---+````+---#```C`#-->`L

````````#`````#````````````#`````#`````

````````#`````#````````````#`````#`````

````+---#`````#````````+---#`````#`````

````:```#######````````:```#######`````

````:`````SW1``````````:`````SW2```````

````:``````````````````:```````````````

N`--+------------------+```````````````

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