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Discussion Starter · #1 ·
It's driving me nuts. Old house, 2 wire (no ground circuit), 3 way light circuit. Light is upstairs at head of stairs, as is one 3 way switch. Other 3 way switch is in the kitchen (don't ask me why, its 2 rooms away from the stairs). Added a 3 way switch at foot of stairs to replace the one in the kitchen. Here's where the problem starts.

Most of the wiring is inaccessible, the feed comes from the basement to an outside panel on the porch, back into the wall and up stairs. A number of lights & outlets on this one circuit, attic light, 2 bedroom lights, bedroom outlets. The drawing below shows the layout, and what I have ascertained so far. The power off readings are with an ohmmeter to a known ground. The power on readings are between the terminals as noted. WTH are some of these wires doing connected to neutral, and others have voltage? How can they ring to neutral and then have voltage on them?

Next up - check voltage on each switch to neutral with power on, and string a wire from upstairs to downstairs to ring out individual wires.

I will figure this out, and I will fix it - may just take my remaining years, but I will prevail. One more thing - my garage was built and wired much later, but guess what - I had to go through and rewire all the light switches - idiot switched the neutral. Doubtful that the same electrician did both jobs, but makes one wonder.

Oh yeah, dang the idiot to heck that spray foam filled the boxes.....
 

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Discussion Starter · #3 ·
My suggestion would be to get a real electrician over there to help you out.:yes:
Funny! I happen to be a "real" electrician. AND, i think I have it - see diagram. If it is wired this way, it will play havoc trying to get the new switch in place of the old - physical access and all that!
 

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John
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You guys both have me confused.:blink:
This is how I wire 3-ways. The side terminals are never wired to either the load or the source.
 

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Discussion Starter · #5 ·
John, what you have pictured is the normal way to wire 3 ways. What i discovered here is to expect the unexpected. The last drawing I posted above pretty much has to be the way it was wired. That's the only way neutral can be switched in a 3 way. Who knows who came up with it. But then, a lot of stuff was done 80 or 100 years ago that isn't common today. For example 3 of the old 2 wire cotton fabric cables spliced together in the ceiling and friction taped all over. Looks like what I'll end up doing is cutting and capping in another junction box all the existing wires or wire nutting in the box where the downstairs switch is removed, and running a whole new circuit for the light. Never easy!
(just looking at the switch in the picture should give an idea how old this stuff is).
 

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I have never seen a three way switch wired that way. The neutral is not to be connected to the switch. Normally you bring the power in one box and the two wires going to the light out the other box. You run a three conductor wire between the boxes and twist all neutrals together. The power (black wire) goes to the colored screw on the switch and the red and black of the the three conductor wire go on the other two screws. The black wire for the light go on the same screw as the power ON THE OTHER SWITCH.
TOM
 

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Discussion Starter · #7 ·
I have never seen a three way switch wired that way. The neutral is not to be connected to the switch. Normally you bring the power in one box and the two wires going to the light out the other box. You run a three conductor wire between the boxes and twist all neutrals together. The power (black wire) goes to the colored screw on the switch and the red and black of the the three conductor wire go on the other two screws. The black wire for the light go on the same screw as the power ON THE OTHER SWITCH.
TOM
Go back in time and tell that to the "electrician" that wired this house! :wallbash:
 

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Go back in time and tell that to the "electrician" that wired this house! :wallbash:
I agree, I have found light switches in the neutral leg in old houses. The bad thing about switching the neutral someone may think they have isolated power by turning the light off only to find the hot wire at the light fixture Hot!
Tom
 

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John
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I think you will first need to find out where the real line comes from. I doubt you have a neutral in the switch box, any white wires are likely travelers. You would need to take your meter and check between a known neutral and the terminals on the switch rather than going between the switch terminals. I usually hook up an extension cord to a known outlet and use it for my reference when the house isn't grounded. Once you know where the real line and real neutral are, you have a starting point.
Being an old house, I would guess the line and neutral go to the light box from the fuse/breaker box. The neutral is connected to the light, the line continues to the common on the first 3-way switch. Two travelers go from the side terminals (the common may also be on the side but isn't switched where the other two are) to the side terminals of the second 3-way. The common of the second 3-way goes to the line side of the light.:smile:
Edit- I would also pull the appropriate fuse, clean out the switch boxes and update the switches. Most of mine old enough to be of that configuration have expired.

EDIT II - Sorry, I was typing while you and Tom were posting so I just saw the last responses
 

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John
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I know what you mean about old houses. Place I'm in had a 60 amp main fuse box and a subpanel with breakers but no mains. I wanted to cut a wire in the basement but couldn't figure out which fuse to pull so I just pulled the mains. When I cut the wire there was all kinds of lightning. Went back and took a closer look and found that the subpanel was wired to the meter and the fuse box was tapped off those bars. The wire I cut was being fed by the sub panel. :eek:
After that, I found the electric dryer wired with 12-2 w/ground and "protected" by a 40 amp breaker.... lessee, 30 amp device, fed with 20 amp wiring, protected by a 40 amp breaker... where is the fuse here???:eek::eek:
Not the end of the story but I think I have it pretty much in shape now. :smile:
 

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have you shown all of the current carrying conductors? there is only one wire from the light to the 2 switches, and 2 between the switches? also, you said that you added a 3 way switch. if you kept the existing 3 way switches, you needed to add a 4 way switch.
 

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Funny! I happen to be a "real" electrician. AND, i think I have it - see diagram. If it is wired this way, it will play havoc trying to get the new switch in place of the old - physical access and all that!
i will say that is a clever use of the switches however.
 

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novice wood hacker
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have you shown all of the current carrying conductors? there is only one wire from the light to the 2 switches, and 2 between the switches? also, you said that you added a 3 way switch. if you kept the existing 3 way switches, you needed to add a 4 way switch.
Actually I think he's getting rid of the three way switch in the kitchen and replacing it with one at the bottom of the stairs so he won't need a four way switch.
 

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It's driving me nuts. Old house, 2 wire (no ground circuit), 3 way light circuit. Light is upstairs at head of stairs, as is one 3 way switch. Other 3 way switch is in the kitchen (don't ask me why, its 2 rooms away from the stairs). Added a 3 way switch at foot of stairs to replace the one in the kitchen. Here's where the problem starts.

Most of the wiring is inaccessible, the feed comes from the basement to an outside panel on the porch, back into the wall and up stairs. A number of lights & outlets on this one circuit, attic light, 2 bedroom lights, bedroom outlets. The drawing below shows the layout, and what I have ascertained so far. The power off readings are with an ohmmeter to a known ground. The power on readings are between the terminals as noted. WTH are some of these wires doing connected to neutral, and others have voltage? How can they ring to neutral and then have voltage on them?
your ohmeter was reading through the light bulb filament when you read a short to neutral on the lower switch. if you unscrew the bulb it will go away.

Oh yeah, dang the idiot to heck that spray foam filled the boxes.....
your voltage readings that are other than 120 vac or 0 vac, are an indication that your neutral (path) may have a weak connection.
 

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Discussion Starter · #17 ·
have you shown all of the current carrying conductors? there is only one wire from the light to the 2 switches, and 2 between the switches? also, you said that you added a 3 way switch. if you kept the existing 3 way switches, you needed to add a 4 way switch.
Actually I think he's getting rid of the three way switch in the kitchen and replacing it with one at the bottom of the stairs so he won't need a four way switch.
Bingo!

your ohmeter was reading through the light bulb filament when you read a short to neutral on the lower switch. if you unscrew the bulb it will go away.

your voltage readings that are other than 120 vac or 0 vac, are an indication that your neutral (path) may have a weak connection.
Nope, bulb was out of the socket. The 20 and 60 volt readings are phantom readings - typical on a digital meter where 2 wires run in close proximity. But the ohmmeter in an unpowered circuit doesn't lie, there was a neutral connection to the switch.

Was at the local electrical supply store today and BSing with them - they have seen that circuit before- old houses.
 

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Bingo!



Nope, bulb was out of the socket. The 20 and 60 volt readings are phantom readings - typical on a digital meter where 2 wires run in close proximity.???? never heard of that But the ohmmeter in an unpowered circuit doesn't lie, there was a neutral connection to the switch. i don't see that on your schematic

Was at the local electrical supply store today and BSing with them - they have seen that circuit before- old houses.
let us know what you find out
 

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novice wood hacker
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your voltage readings that are other than 120 vac or 0 vac, are an indication that your neutral (path) may have a weak connection.
Actually, it's a normal occurrence caused by Induction. The wire is disconnected at both ends (due to the switches being open) and because the powered wire runs right next to it, the magnetic field from the power wire induces current into the unconnected wire. It will show voltage readings like he is seeing, but won't support any kind of electrical load.
 

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Discussion Starter · #20 ·
Nope, bulb was out of the socket. The 20 and 60 volt readings are phantom readings - typical on a digital meter where 2 wires run in close proximity.???? never heard of that But the ohmmeter in an unpowered circuit doesn't lie, there was a neutral connection to the switch. i don't see that on you schematic

Was at the local electrical supply store today and BSing with them - they have seen that circuit before- old houses.

let us know what you find out
You mean this neutral?
 

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