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Author Topic: 2-Wire Appliance On/Off Switch or Outlet?  (Read 10389 times)

Offline stylekyle

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2-Wire Appliance On/Off Switch or Outlet?
« on: June 12, 2012, 11:41:22 am »
Any one know of a z-wave 2 wire on/off appliance switch or outlet?  I need to control a fan in my attic, so I can't use a dimmer.  I have old wiring in my house and don't have  a neutral or a ground.  All of the other GE dimmer switches that I used didn't need a neutral or a ground.  But for some reason, the GE hard wired outlet, or the two on/off switches that I've found all require a neutral.

Anyone have an ideas?  I guess, I could just wire in a normal outlet, and then use a plug-in z-wave on/off module...

Offline hsmaier

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #1 on: June 12, 2012, 12:13:57 pm »
I use a Ranco to control my attic fan

http://www.etcsupply.com/manuals/ranco_etc.pdf

I had problems a few years ago with the bi metalic thermostat up in the attic for the attic fan. Even after replacing it the fan would sometimes still be running at 2 AM long after it was cool outside.
I ordered and mounted the Ranco in a closet just below the attic ceiling.
Once I programmed it with the 90 degree on temperature setting and 85 degree off temperature I've had no more problems with the attic fan running for long periods of time
Vera 2 U14, Vera 2 U15, Two Trane TZEMT400AB32 Thermostats. Insteon Light Switches, Insteon Outlets, Power Linc Modem.

Offline stylekyle

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #2 on: June 13, 2012, 11:19:59 am »
I use a Ranco to control my attic fan

http://www.etcsupply.com/manuals/ranco_etc.pdf

I had problems a few years ago with the bi metalic thermostat up in the attic for the attic fan. Even after replacing it the fan would sometimes still be running at 2 AM long after it was cool outside.
I ordered and mounted the Ranco in a closet just below the attic ceiling.
Once I programmed it with the 90 degree on temperature setting and 85 degree off temperature I've had no more problems with the attic fan running for long periods of time

That's cool.  Unfortunately, it won't work for me because I don't have vents in my attich, and need to make sure the attic door is open and windows are open before I want it to run.  I'm hoping to have it on z-wave, so that i can just run a scene for it to run a set amount of time.  And that way i don't have to climb up in the attic to turn it on.

Offline aschwalb

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #3 on: June 13, 2012, 01:18:09 pm »
Any one know of a z-wave 2 wire on/off appliance switch or outlet?  I need to control a fan in my attic, so I can't use a dimmer.  I have old wiring in my house and don't have  a neutral or a ground.  All of the other GE dimmer switches that I used didn't need a neutral or a ground.  But for some reason, the GE hard wired outlet, or the two on/off switches that I've found all require a neutral.

Anyone have an ideas?  I guess, I could just wire in a normal outlet, and then use a plug-in z-wave on/off module...

What two wires do you have if one is not ground or neutral? 

Offline stylekyle

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #4 on: June 13, 2012, 02:00:59 pm »
Any one know of a z-wave 2 wire on/off appliance switch or outlet?  I need to control a fan in my attic, so I can't use a dimmer.  I have old wiring in my house and don't have  a neutral or a ground.  All of the other GE dimmer switches that I used didn't need a neutral or a ground.  But for some reason, the GE hard wired outlet, or the two on/off switches that I've found all require a neutral.

Anyone have an ideas?  I guess, I could just wire in a normal outlet, and then use a plug-in z-wave on/off module...

What two wires do you have if one is not ground or neutral?

Well, good point.  I guess what I meant to say is, I don't have a dedicated ground, and I'm having trouble determining the neutral.  Other z-wave devices i've used, it didn't matter which one was the neutral and which one was hot.  It appears the appliance switches all require a ground and for you to know which one is the neutral.  I'm guessing the appliance switches must power the z-wave device using the ground because they can't put a small current through the motor like they would with a light.

Offline stylekyle

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #5 on: June 13, 2012, 02:11:34 pm »
so, according to this article, it doesn't look like anything exists. 

http://cocoontech.com/forums/topic/18818-best-ha-hardware-for-switches-with-no-neutral/

It would be a headache trying to run romex to my attic, so it looks like i'm sol.

Offline aschwalb

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #6 on: June 14, 2012, 09:35:30 am »
Well, good point.  I guess what I meant to say is, I don't have a dedicated ground, and I'm having trouble determining the neutral.  Other z-wave devices i've used, it didn't matter which one was the neutral and which one was hot.  It appears the appliance switches all require a ground and for you to know which one is the neutral.  I'm guessing the appliance switches must power the z-wave device using the ground because they can't put a small current through the motor like they would with a light.

I am not sure the a ground is required to make the zwave function..  Have you tried one?  I would have thought the ground was for safety since most appliances are grounded...  Since you dont really have a ground anyway... 

Offline aa6vh

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #7 on: June 14, 2012, 10:39:41 am »
On a two wire switch, there is no neutral. Only a line and a load. The neutral is located on the other side of the motor (assuming that the switch is located in the circuit before the motor). Without a third neutral wire, and not being able to pass a little bit of current through the motor when off, there is no power for the Zwave radio.

Routing current through the ground wire is a no-no, as this can set up a dangerous situation.

Offline stylekyle

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #8 on: June 14, 2012, 03:18:43 pm »
On a two wire switch, there is no neutral. Only a line and a load. The neutral is located on the other side of the motor (assuming that the switch is located in the circuit before the motor). Without a third neutral wire, and not being able to pass a little bit of current through the motor when off, there is no power for the Zwave radio.

Routing current through the ground wire is a no-no, as this can set up a dangerous situation.

Ah, I get it.  Thanks aa6vh.  So how do the plug-in appliance modules work?  I guess I can try plugging one of those into an older outlet in my house that I know is being fed from knob and tube.  It probably won't work.  But if it does, I guess I can just change the switch in the attic into standard outlet, and then plugin an appliance module and then wire on a plug to the fan. 

Offline aa6vh

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #9 on: June 14, 2012, 05:44:21 pm »
So how do the plug-in appliance modules work?

Unlike switches, electrical plugs always have the neutral line connected to it.

In most newer houses, even though switches only will have the two wires (line and load) connected, the switch box will have the neutral line (unconnected) in the electrical box holding the switch. When wired like that, it is quite easy to tap directly into the neutral line, and thus have power for the ZWave radio. Older houses often did not do that.

I would suggest consulting a qualified electrician. He might be able to think of ways of re-wiring things to accomodate the ZWave switch.

Offline DaveGee

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #10 on: June 14, 2012, 07:14:18 pm »
When it comes to neutrals @ the switch box sometimes the age of the home has little to do with it. My previous home was built in the 70s ... Okay to some that's _old_ ... But only to SOME! :) anyway the person who did the wiring seemed to have a love of running power & neutral to the load/fixture in ever single ceiling light, fan and chandelier and just loved running a single set of wires where the white wasn't a neutral but instead a return power wire... Oh and while you're supposed to blacken the white wire either with tape or black marker he never did. Nutting like trying to do home automation crossing your fingers hoping to see a neutral only to find the lone white wire is just the return hot. :(

Oh well the joys of electrical wiring never ceases to end... ;D

Offline oTi@

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #11 on: June 15, 2012, 07:00:37 am »
[...]I guess, I could just wire in a normal outlet, and then use a plug-in z-wave on/off module...
Being able to put an outlet there, implies you have a neutral. If you currently only have a switch there and there is precisely 2 wires (besides ground) in that box, both connected to the switch, then you don't appear to have a neutral available.

What is the switch that is there currently switching?

Ground is for safety, not used to carry current / close circuits / power things, etc.

Most Z-Wave on/off switches can switch 'any' load, and are relay based, thus requiring a line and neutral. 'Only' if it's switching incandescent lighting, would you not need a neutral, because a small current can be sent through the load (i.e. the bulb) without harming it.
« Last Edit: June 15, 2012, 07:02:14 am by oTi@ »
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Offline stylekyle

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #12 on: June 15, 2012, 10:52:37 am »
Ground is for safety, not used to carry current / close circuits / power things, etc.

There is a switch at the door going into the attic that turns on a light in the attic.  Coming from that light, conduit goes to another switch that switches the attic fan on and off. 

Basically, the first switch has to be on to power the light and the fan.  The switch before the fan allows me to have just the light on.  So I guess the light and the fan are in parallel. 

My thought was, I'll just leave the switch at the bottom of the stairs on all the time and put the light bulb on a screw-in motion sensor.  Then, where the second switch is, i'll put in a z-wave appliance device (switch, outlet, or plugin switch) to control just the fan.

So I guess I'm not sure if there is a neutral.  I'm guessing the fans polarity must be correct, because the motor spins the right direction.

Offline oTi@

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #13 on: June 15, 2012, 12:28:58 pm »
At a minimum, there will be neutral at the light and at the fan.
The fan is 'wired in' to the second switch, right, not plugged into an outlet?
Can you describe the situation in the second box, in terms of wires (how many cables, what wires/colors, what is connected to what, etc.)?

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Offline stylekyle

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Re: 2-Wire Appliance On/Off Switch or Outlet?
« Reply #14 on: June 19, 2012, 12:23:07 pm »
At a minimum, there will be neutral at the light and at the fan.
The fan is 'wired in' to the second switch, right, not plugged into an outlet?
Can you describe the situation in the second box, in terms of wires (how many cables, what wires/colors, what is connected to what, etc.)?

Okay, I went up there and looked closer at things, and the knob and tube wiring insulation has a black leg and a white leg.  Which I thought was strange, because everywhere else in the house, the knob and tube wires are only black.    Anyway, the K&T wiring goes into the light, and then come out of the light as romex into the switch that controls that fan that I want to turn into the z-wave switch.  In there, I have one black wire, and one white wire coming from the romex, and then a black and white wire that go to the fan.  I've attached a few photos photos. 

Looks like that white wire might actually be a neutral?

I haven't opened the switch (not pictured) that feeds the light and fan (pictured) yet... but i'm assuming it is just switching the hot, and if I just leave the switch on, a z-wave switch would operate normally in the second switch before the fan.