Detached garage 3-way over 2 wires

Reply

  #1  
Old 01-21-21, 04:13 PM
D
Member
Thread Starter
Join Date: Jul 2014
Posts: 104
Received 0 Votes on 0 Posts
Detached garage 3-way over 2 wires

I've got a detached barn/garage that has an existing 2 wire cable running to the lights on the outside. Its attached to a 3 way switch in the house and another 3-way switch in the barn.

I'm finishing the barn into an office and we are working on re-wiring including adding another light and another 3-way (i guess 4-way now) switch to this circuit. Low and behold when we went to do the wiring we discovered it a 2 conductor cable running from the house.

A few years ago i installed a Z-Wave switch in both the barn and house location so I am guess those are talking to each other over the air which allows this whole thing to work. When i installed those switches i'm sure i would have simply replaced the old wires in the new switch hot, neutral, and traveler terminals.

I'm going to not hurt my brain to figure out how this ever worked - zwave or not. My question is - is there a way i can run multiple lights and 2 switches in my barn in a regular 3-wire 3-way setup. Then add the house switch that is connecting to the barn via a 2 conductor cable? I bet i could do it with a relay or something like that - but not sure if there is a clean way to make this happen without ripping up the old 2 wire from house to barn.

Appreciate the help!





 
  #2  
Old 01-21-21, 06:53 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,367
Received 1,397 Votes on 1,294 Posts
If you only have two wires (plus ground) from the house to the barn...... then you have power to the barn.... only. Using zwave is about the only way to have three way control.

If you are turning the barn into an office.... it sounds like it's time for more power and then switching could be added in the same conduit.
 
  #3  
Old 01-21-21, 07:22 PM
D
Member
Thread Starter
Join Date: Jul 2014
Posts: 104
Received 0 Votes on 0 Posts
Yea i hear you but i have 2 cables going to the barn and both are romex 14/2 with ground. No third wire. It definitely worked before i swapped the zwave in and works now. Thats the mystery...

I've been doing research on "Chicago 3 way" and other older ways to make this work. This circuit was most likely put in during the 60s so its not super old. Maybe they wired it to share the neutral between the circuit that's feeding the barn and then use the 2 wires as the travelers. Definitely not code today but it seems to work.

Problem is i don't know how to add another switch to it....
 
  #4  
Old 01-21-21, 07:40 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,367
Received 1,397 Votes on 1,294 Posts
It's possible with two cables. Both cables must be on the same circuit.
One cable carries always hot and neutral from the house to the barn.
The second cable is only the two traveler wires.
The travelers are only usable at one end..... light at either the house or the barn.... not both.

14-2 is only 15A of 120v power. Is that enough for your requirements in the barn ?
Do you need a diagram of the wiring ?
 
  #5  
Old 01-21-21, 07:45 PM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,341
Received 113 Votes on 104 Posts
It's working now as you said.

Do this.

(Turn off the power)

Label (do not use the words like left, middle) the wires on the 3 way switch in the barn and then remove that switch.

Run a 3 conductor cable from that switch location to the third switch location.

Get a 4 way switch and connect the two old traveler wires (that went to the lighter colored terminals of the old 3 way switch) to the lighter terminals of the 4 way switch.

Connect the matching colored wires of the new cable to the two darker terminals of the 4 way switch.

Take the 3 way switch over to the third location and connect the matching colored wires of the new cable to the ligher colored swirtch terminals.

Connect the remaining wire to the dark terminal of the 3 way switch.

Back at the old 3 way swithc location onnect the old common wire to the remaining wire of the new cable.

Run a (2 wire) cable from the existing light to tne new light.

 
  #6  
Old 01-22-21, 07:51 AM
D
Member
Thread Starter
Join Date: Jul 2014
Posts: 104
Received 0 Votes on 0 Posts
Thanks! I will try that today and see what happens.

I wasn't entirely accurate in my description - the power from the house to the barn is 220V on a 60amp circuit. So the power to the barn is on its own double breaker. The switch is on another circuit and i assume they are on the same side of the box and sharing the same neutral and hot.

So i think this works because i'm tapping into the barn neutral which is technically the same neutral back at the main box. But i've also read this only works if they are on the same circuit and i'm not sure why the breaker would make a difference.
 
  #7  
Old 01-22-21, 08:20 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,341
Received 113 Votes on 104 Posts
The original wiring of the 3 way switch might possibly violate one or more of the following but I will not suggest now that you hurt your brain to find out. Usually however, needing a neutral and tapping into the wrong one will produce a working circuit or subcircuit.

* The matching neutral (from the same branch circuit) must physically accompany the hot,


* Only one 120 volt only or 120/240 volt or 240 volt only feed or branch circuit is allowed from the main house to the barn, (It is called a feed when it goes to a panel before wiring branches off to outlets.)


* Switches are put in the hot path, not the neutral path (except for certain neutral switching generator and solar installations when all hot conductors are also switched at the same location and simultaneously).


* Only the neutral that came with a branch circuit may be used to return current from things (loads) powered by that circuit.


My suggested wiring does not make the problem worse but also does not make it any better.
 

Last edited by AllanJ; 01-22-21 at 08:53 AM.
  #8  
Old 01-22-21, 08:38 AM
D
Member
Thread Starter
Join Date: Jul 2014
Posts: 104
Received 0 Votes on 0 Posts
Well might i be better to just build a small device that feeds the switches with a low voltage signal and then i use a relay to turn on/off the power to the barn lights with the barn power sub panel? I just don't know how bad the current scenario is and what danger is poses.

I can easily build a device that senses a low voltage switch from multiple switches and then controls a relay to swap on/off. Future generations won't know what this strange device is in my utility room or why its necessary. Maybe i'll leave a note in the box...
 
  #9  
Old 01-22-21, 07:31 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,367
Received 1,397 Votes on 1,294 Posts
I wasn't entirely accurate in my description - the power from the house to the barn is 220V on a 60amp circuit.
Not even close !
You're playing a dangerous game by using just two wire switching,

If you are getting your power in the barn to run the circuit.. how are you doing it on only two wires ??
If you are getting the power in the house.... you are using a neutral from a different circuit to run the lights.
 
  #10  
Old 01-22-21, 07:50 PM
D
Member
Thread Starter
Join Date: Jul 2014
Posts: 104
Received 0 Votes on 0 Posts
I did some more discovery today and they way they did it is was the lights are powered from the house switch and uses the neutral from the barn sub panel. The barn was originally only a 120 circuit and the light circuit and the barn sub shared a neutral.. I assume they were on different legs in the Main. I upgraded the barn with 220 a few years ago but left the lights the way they were.

From my very basic understanding and no expert knowledge this setup means the lights could overload the sub panel neutral and it wouldnít trip the breaker like it should. However the lights are drawing about an amp so Iím not too concerned.

but if this is worse than I believe by all means this is why Iím asking...

 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: