Smart Switch when no Neutral is available
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17 posts in this topic

Hey all -

 

Happy new year -

 

New house, and still trying to figure out all the wiring (definitely non-standard!)

 

I have switches/dimmers installed in the main and upper floors with no problem.  All those boxes had neutrals in a pig-tail.

 

However, when I went to install a switch in my daughters room (in the lower level) there was no neutral wire (no pig-tail either).

 

I tried installing the switch, but it wouldn't work.  Is there an option for smart switches when no neutral is available?

 

Thanks!

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You can use the ground wire -- which is mostly a bare copper wire. I accidentally wired one of mine that way and it worked. I didn't realize it was wrong until I was installing another GE switch and noticed. I have a black wire, white wire and ground wire in my house. Some circuits also have a red wire, which is known as the traveler wire and used to install extra switches down the line on the same circuit. 

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Here are some photos of my wiring. One is where I accidentally wired my neutral into the ground...which worked. I fixed it since. The other is before I installed an add on switch. The red wire was the travelor. The traveler runs to the other GE switch on another outlet. [

 

 

post-4162-0-38848900-1483459495_thumb.jpg

post-4162-0-16967900-1483459540_thumb.jpg

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I agree that he ground is for ground and not neutral, but why does my original switches not have nuetrals. See the travel switch. Not of my orignal switches use the ground or the nuetral.

Da! I just thought, the smart switch needs power, thus the nuetral switch, while the original switches just needed to complete a circuit. So never mind. It should be noted that when I installed the GE add on switch (see second picture) I did not use the line or load (black lines). Just push in the red traveler switch. Guess it signals the main GE switch to turn on.

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You can't always go by the color of the wires to know what they are used for either, I have seen travelers that are blue, yellow, and red in different old circuits.  Most of the time there will be a neutral that runs through the box that can be used with the Z-Wave switches but as Cover pointed out would not have been used with normal switches since they had no electronics inside the switch to power.  Also in some ceiling fans I have seen a red wire that was live for the fan and a switched black for the light.  A few times over the years I have also seen where someone switched the neutral wire instead of the hot wire, which technically works but definitely isn't recommended and should be corrected.

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I agree that he ground is for ground and not neutral, but why does my original switches not have nuetrals. See the travel switch. Not of my orignal switches use the ground or the nuetral.

Think of it this way. The neutral wire is used as a return path. I know this is AC current and not DC, but think of it like the power coming in on the hot wire and out on the neutral. (This is an over simplification but it gets the point accross)

A regular switch is just breaking the hot wire, so when it is in the off position there is no longer a return path... therefore any electronics in the switch cant function when the switch is in the off position.

The old z-wave switches that did not require a neutral actually did use the load side as a return path, but this caused a very small amount of power to constantly be sent through the light bulb. Even when the switch was "off" it was never "truly off". That worked ok with incandescent bulbs, but now in the days of LED, that no longer works well.

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Is there only one cable (a cable has more than one conductor) that enters the box? Y/N

If YES how many conductors in that cable? 2, 3, more?

If NO then how many cables enter the box?


You could have, if it's only one cable, a switch leg meaning that the hot and neutral from the breaker box enter the box at the fixture first. The neutral is connected to the fixture and the hot runs out of the fixture box (without being connected to the fixture) to the switch and then back to the box with the fixture where it connects to the fixture to complete the circuit. So you end up with a hot lead coming in to the switch box, and a switched hot leg coming back out that goes back to the fixture. No neutral needed in the switch box. Now if you had a switch with a light in it then you would need to bring a neutral into that box but only for the light built into the switch, not for the fixture being controlled by the switch.

You'll find an decent explanation with graphics here:

http://www.electrical-online.com/adding-an-outlet-or-a-receptacle-from-a-switch-box/

 

Do not use a ground conductor as a neutral. You risk someone getting shocked and you're energizing a bare conductor, so any metal box is now part of that circuit, and the metal screws on the switch or outlet cover plates are now part of the circuit. It's wrong (as in violates the National Electrical Code) and dangerous (as in can kill) and if an electrical fire ever started in your house and the insurance inspector finds your creative wiring you could end up with no insurance coverage.

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Thanks all.  Is it possible to get any of the old switches anywhere (those that don't require a neutral?  I'm not smart enough to figure out heavy duty wiring and don't want to spend a ton on this one switch - but would like them connected to the rest of my Iris ecosystem.

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I had a similar situation with a switch in my shop.  They did not bring down a neutral wire.  The switch turns on the light in my shop attic.  So they just brought down and switched the line voltage on and off.

 

In my case it would not be a huge deal to bring down a neutral as the shop has unfinished walls.  Except that I had put peg board over this wall so I would have to run behind it.  It was really more effort than I wanted to put in to this, so I bought a connected bulb and then put a contact sensor on the attic door.  The light comes on when I open the door, goes off when I close it.  You could do something similar.  Maybe bypass the switch internally and put a blank cover over it.,then put a push button on it

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Thanks all.  Is it possible to get any of the old switches anywhere (those that don't require a neutral?  I'm not smart enough to figure out heavy duty wiring and don't want to spend a ton on this one switch - but would like them connected to the rest of my Iris ecosystem.

I've seen them from time to time on eBay. Do your homework and be sure of the model number you are looking for -- the eBay ads can be vague regarding what switches are being offered.

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Be careful when buying Z-Wave switches on eBay.  The majority of the sites offering these in quantity are selling reconditioned switches.  I bought a bunch of these from one seller and none of them worked.  They were obviously returned items.  Some of them even had burn marks near the contacts lugs where they had been shorted out.

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So answer me this:

Your light has a neutral wire to complete the circuit.

Your smart switch requires a neutral wire to power the WiFi (low draw)

Older dryers (3-wire) did not have digital controls

NEC changed the code for new homes to be 4-wire so that there would be a neutral for the control circuit.

It is perfectly legal to run a new dryer (with controls) on a 3-wire circuit, i.e., uses ground to complete the control circuit.

What is the difference using the ground to complete the control circuit with a smart switch vs a dryer?

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