Screwed up replacing old 3-way switches


Old 05-30-05, 09:56 AM
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Screwed up replacing old 3-way switches

I thought ( ) I had correctly replaced some old 3-way switches with new ones but I managed to bung everything up.

Here is what I have so far:

Wall "A" is on the wall facing the breaker box and wall "B" is on the wall to the breaker's right. I don't know if that matters much regarding the in-wall wiring but I figure I would include it anyhow.

When both are off, the A switch has its light lit (a neon bulb inside the toggle) but B is dark.

When A is off and B turns on, the light on A goes out.

B's light is never on unless A is on and you turn B off.

The wire colors are (for whatever its worth):

A: White on common and black on the travelers.
B: White on common and black & red on the travelers.

The voltages are:

(A on, B off)

A: 120 (common) 120 (traveller1) 45 (traveller2)
B: 120 (c) 45 (T1) 120 (T2)

(B on, A off)

A: 34 (c) 120 (t1) 34 (t2)
B: 35 (c) 35 (t1) 0 (t2)

(A & B on)

A: 120 (c) 120 (t1) 120 (t2)
B: 120 (c) 120 (t1) 0 (t2)

(A & B off)

A: 0 (c) 120 (t1) 0 (t2)
B: 0 (c) 0 (t1) 0 (t2)

Like I said, it only half-way works and it seems as though I have voltages that shouldn't be so I'd like some help if possible.

Thanks in advance!
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Old 05-30-05, 10:32 AM
Join Date: Sep 2000
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First of all, those voltage readings other than 0 and 120 are phantom, and should be treated as if they were zero.

Next, we don't have a complete picture unless we also have the wiring information from the load controlled by these switches. This is where everything comes together.

Next, I don't care much about those little lights in the switches. After all, lighting those isn't the purpose of the switches (is it?). So what I'd really like to know is what is the load controlled by the switches, and is it on or off for each position of the switches (A-off/B-off, A-off/B-on, A-on/B-off, A-on/B-on).
Old 05-30-05, 12:57 PM
Join Date: Sep 2002
Location: welland ontario
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From your voltage reading try this.
Put the wire at A listed a T1 on the common. It appears to be your power feed. It always has 120v no matter how A is set. Put the other two wires on the travellers.
The same at B. The wire you list as the T1 appears to be the common.
If that doesn't work then.
Do you still have the old switches? Can you put them back and make it work properly?
If not then tell us all the wires in each switch and at the light that this switch controls.

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