# Commercial three way switch problem



## tcroal (Jan 30, 2017)

So here is my problem. I have a commercial building, technically two buildings, joined in the center by a bridge called "the link". The link is fully lit and climate controlled, with seven ceiling mounted light fixtures running down the hall. Two of these lights, are 24/7 lights powered by a circuit we still haven't found. 

The other five, run off of a three way switch at either end of the hall, the power being fed from a panel around the corner in one of the two buildings. The plan for this afternoon, was to remove the three way switches and replace them, one doesn't work and they are probably about forty years old each.

So we shut off the power, take out the switches, turn it back on, find the hot wire, and wire nut it off for safety. Then we go to tone out the travelers for continuity and this is where it gets weird, each of the two traveler wires, neither of which are presently connected to the power (as far as we know) has 100 volts on it. 

Obviously it worked before, at least until one of the old switches **** the bed, so we toned them out to confirm continuity, shut the power back off, and proceeded with the installation of the new 3 way occupancy sensors, which didn't work. They functioned as if one were wired incorrectly, my best guess is the driver in the occupancy sensor (Lutron Maestro) doesn't know what to do about the constant voltage on the traveler wires and neither do we. So we shut the breaker back off and called it a day, going back tomorrow to investigate further. Any thoughts good people of the internet?


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## The_Modifier (Oct 24, 2009)

Do you have an electrician on staff? They may properly be able to diagnose the problem for you. Over the internet, it can be conceived many ways from how you explained it.

The lighting system voltage, the one of 11 ways that a 3 way system can be connected ....etc.


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## sbrn33 (Mar 15, 2007)

I am guessing you have ghost voltage and need to set those motion switches up as 2 single poles in parallel. I like modifiers idea also.


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## tcroal (Jan 30, 2017)

Not licensed, unfortunately... I went to school for it then got recruited to this property management company, my partner in crime on this job was an apprentice for about a decade. If it comes to it we will call in our usual contractor to get everything working properly, we don't have the staff to cover running a new feed and such... the lights are mounted to a hard ceiling with no access panels


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## tcroal (Jan 30, 2017)

I hadn't considered that it could be ghost voltage, I guess we will have to find out tomorrow morning. I just really hate admitting defeat haha. Thanks for the input so far guys.


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## PlugsAndLights (Jan 19, 2016)

tcroal said:


> Not licensed, unfortunately... I went to school for it then got recruited to this property management company, my partner in crime on this job was an apprentice for about a decade. If it comes to it we will call in our usual contractor to get everything working properly, we don't have the staff to cover running a new feed and such... the lights are mounted to a hard ceiling with no access panels


Give further thought to sbrn's suggestion of setting these up as single 
poles in parallel. Draw out how it's wired now and go from there. 
P&L


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## telsa (May 22, 2015)

tcroal said:


> So here is my problem. I have a commercial building, technically two buildings, joined in the center by a bridge called "the link". The link is fully lit and climate controlled, with seven ceiling mounted light fixtures running down the hall. Two of these lights, are 24/7 lights powered by a circuit we still haven't found.
> 
> The other five, run off of a three way switch at either end of the hall, the power being fed from a panel around the corner in one of the two buildings. The plan for this afternoon, was to remove the three way switches and replace them, *one doesn't work *and they are probably about forty years old each.
> 
> ...


Someone changed the circuit to bypass one of the 3-ways... is a pretty good bet.

That someone was also likely 'lost' ... and thrilled to get things back up and running.

You need a (commercial) journey-man with all of the toys to solve this. 

You could easily have the link fed from both A and B structures.


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## Big John (May 23, 2010)

You have a wiggy or other low impedance voltmeter, or even a 120V test light? Use that for troubleshooting presence of voltage.


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## wendon (Sep 27, 2010)

Are they switching the neutral? I've never 3-wayed occ sensors. Can you install them at both locations or are they like dimmers?

Sent from my SAMSUNG-SM-G870A using Tapatalk


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## TGGT (Oct 28, 2012)

Scrap the existing circuit and just start over and wire it right, then you don't have to wonder about it anymore.


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## sbrn33 (Mar 15, 2007)

TGGT said:


> Scrap the existing circuit and just start over and wire it right, then you don't have to wonder about it anymore.


Who is saying the circuit is wrong? The problem is we have a janitor trying to wire a complicated circuit. You may be the reason they don't want to call an electrician.


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## TGGT (Oct 28, 2012)

sbrn33 said:


> Who is saying the circuit is wrong? The problem is we have a janitor trying to wire a complicated circuit. You may be the reason they don't want to call an electrician.


Reading his other replies it doesn't matter, he said they don't have the staff or means to rewire.


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## sbrn33 (Mar 15, 2007)

TGGT said:


> Reading his other replies it doesn't matter, he said they don't have the staff or means to rewire.


Why would you rewire the whole circuit? 
He had a bad 3 way switch and wants to put in motion switches instead.


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## splatz (May 23, 2015)

Backing up, did you verify that the three way switch that went bad was really the problem? I wouldn't expect too much from the 3-way occupancy sensors until I was sure the wiring works with plain switches. 

Do the sensors need neutrals, and are the neutrals present at both switches? 

If the sensors bootleg their neutral through the ground, could it be a problem that the ground path isn't common at both sides? Just thinking out loud. 

Have you seen these?


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## TGGT (Oct 28, 2012)

sbrn33 said:


> Why would you rewire the whole circuit?
> He had a bad 3 way switch and wants to put in motion switches instead.


I think it's a waste of time trying to figure out why it's not working and favor wiring it how they know it WILL work. They could've had working lights by now.

Still doesn't matter since they don't seem capable of even doing that.


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## sbrn33 (Mar 15, 2007)

TGGT said:


> I think it's a waste of time trying to figure out why it's not working and favor wiring it how they know it WILL work. They could've had working lights by now.
> 
> Still doesn't matter since they don't seem capable of even doing that.


So you would charge them 5 or 6 hours instead of a S/C? This is why people don't call electrician. We both know that is something me or you could figure out in ten minutes.


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## TGGT (Oct 28, 2012)

sbrn33 said:


> So you would charge them 5 or 6 hours instead of a S/C? This is why people don't call electrician. We both know that is something me or you could figure out in ten minutes.


I'm not looking at it from a contractors perspective (I'm not a contractor), just what I think they could do as maintenance guys just to get the lights on assuming they understand how to wire 3 ways and read the directions on their OS's.


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## MechanicalDVR (Dec 29, 2007)

TGGT said:


> I think it's a waste of time trying to figure out why it's not working and *favor wiring it how they know it WILL work.* They could've had working lights by now.
> 
> Still doesn't matter since they don't seem capable of even doing that.


If that was a serious option I bet it would be on right now.


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## Barjack (Mar 28, 2010)

I wonder if it could be a farm/California 3 way.

How sure are you that the one panel is the *only* source of power?

To echo what the others have said, I would recommend using a Wiggy to test for voltage on any 3 way system. Tic testers and DMM's always register phantom voltage due to the wires being in such close proximity to one another.


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