Add neutral wire to wall switch

[kinman]

Hi all, most of the HA wall switches need neutral wire but my electrical box do not have neutral wire. Could you please suggest which is correct/better?


ORIGINAL:
                    +------+
white --------------+      |
                    | bulb |
black -----+  +-----+      |
           |  |     +------+
           |  |
           |  |
           |  |
           |   \ switch
           |  |
           +--+

METHOD 1 (Add wire):
                    +------+
white --------------+      |
             +-----/| bulb |
black -----+ |+-----+      |
           | ||     +------+
           | ||
           | ||
           |/||
           LNN1
         +------+
         | x10  |
         |switch|
         +------+

METHOD 2 (Add and modify wire):
                    +------+
white ------+       +      |
            |+-----/| bulb |
black -----+||+-----+      |
           ||||     +------+
           ||||
           ||||
           ||||
           LNN1
         +------+
         | x10  |
         |switch|
         +------+

cheers / kin

 

[Rupp]

Why not use a switch that doesn't require a neutral? Many Z-Wave switches do not need a neutral.
http://store.homeseer.com/store/HomeSeer-Z...rix-W16C61.aspx

 

[kinman]

Yes. I find that those dimmer switch with incandescent lamp do not need a neutral. Switch/plug-in for other lamp and appliances it does require neutral wire.

 

[Steve]

If you have access, you can really pull a neutral from anywhere as long as it is on the same circuit. Be careful pulling from another location/circuit as you will still have voltage on the circuit even if you turn the breaker off.

 

[123]

Your options are limited by the ease of installing a new cable.

Variation #1 runs a new cable from the switch to the light fixture.

Variation #2 runs a new cable to the switch.
It can potentially be a completely different circuit. The existing Line cable is capped within the light fixture.

In theory, you could run a single neutral line in from another location but this is not something you see done by an electrician and probably does not comply with your local electrical code. Hot and Neutral wires are insulated and housed within the cable's sheathing (plus the uninsulated ground-wire). Taken altogether, the cable is fire-rated. If you pull the Neutral wire out of it's sheathing, the fire-rating is lost. You may be tempted to run a 2-wire cable and simply connect one wire, the Neutral, and leave the other unused ... well, that just reeks of "home-brew hacking". If discovered by a home-inspector it compromises the integrity of your home's entire electrical system.

 

[purple_motion]

If you can get to the switch and the light, I would just run a piece of 3-conductor 14-ga wire between the light and the switch.

white = neutral
black = incoming hot
red = switched hot.

I believe this is compliant with code.

MD

 

[kinman]

If you have access, you can really pull a neutral from anywhere as long as it is on the same circuit. Be careful pulling from another location/circuit as you will still have voltage on the circuit even if you turn the breaker off.

Thanks your advise, I will make sure the circuits are complete loops, and the RCD should not be triggered.

 

[kinman]

Your options are limited by the ease of installing a new cable.

Variation #1 runs a new cable from the switch to the light fixture.

Variation #2 runs a new cable to the switch.
It can potentially be a completely different circuit. The existing Line cable is capped within the light fixture.

In theory, you could run a single neutral line in from another location but this is not something you see done by an electrician and probably does not comply with your local electrical code. Hot and Neutral wires are insulated and housed within the cable's sheathing (plus the uninsulated ground-wire). Taken altogether, the cable is fire-rated. If you pull the Neutral wire out of it's sheathing, the fire-rating is lost. You may be tempted to run a 2-wire cable and simply connect one wire, the Neutral, and leave the other unused ... well, that just reeks of "home-brew hacking". If discovered by a home-inspector it compromises the integrity of your home's entire electrical system.

Thanks 123. I have checked the circuits for lighting in my home. They run on seperate circuit breakers and pipes. They also have different standard: no sheathing, no ground/earth, plastic pipe. I prefer variation #1. I will try to trace all existing wires and follow the same practise.

 

[kinman]

If you can get to the switch and the light, I would just run a piece of 3-conductor 14-ga wire between the light and the switch.

white = neutral
black = incoming hot
red = switched hot.

I believe this is compliant with code.

MD

Hi MD, do you suggest me to add a "neutral" wire between the light and the switch? 3-conductor means 3 copper inside the wire? 14-ga is the thickness of copper? thanks!

 

[123]

... They also have different standard: no sheathing, no ground/earth, plastic pipe ...

Interesting; I don't recognize this of electrical wiring. What kind is it?

Knob and tube???

Modern electrical cables used in North America "consist of two to four thermoplastic insulated wires and a bare wire for grounding (bonding) surrounded by a flexible plastic jacket".

The sheathing is colour-coded:
white=typical lighting circuit, 14GA wire, white+black+ground
white=3-way light circuit, 14GA, white+black+red+ground
yellow=kitchen appliances, 12GA wire, white+black+ground
red=240V heaters, 12GA wire, red+black+ground
orange, blue, etc etc

My home is circa 1968 so most of the original cabing is not colour-coded and the sheathing is not thermoplastic but a woven fiber casing (dark green or blue) around a paper wrapping. However, the cable's conductors are insulated with a thermoplastic and are typically white (Neutral) and black (Hot) plus an uninsulated ground wire.

Could you describe your cabling in greater detail please?

 

[purple_motion]

If you can get to the switch and the light, I would just run a piece of 3-conductor 14-ga wire between the light and the switch.

white = neutral
black = incoming hot
red = switched hot.

I believe this is compliant with code.

MD

Hi MD, do you suggest me to add a "neutral" wire between the light and the switch? 3-conductor means 3 copper inside the wire? 14-ga is the thickness of copper? thanks!

Yes 3 conductors in the wire (black, white, red and ground). 14-ga is the thickness. I was just proposing that you remove the old wire and put this one in its place. This just keeps the neutral with the right circuit.

 

[kinman]

... They also have different standard: no sheathing, no ground/earth, plastic pipe ...

Interesting; I don't recognize this of electrical wiring. What kind is it?

Knob and tube???

Modern electrical cables used in North America "consist of two to four thermoplastic insulated wires and a bare wire for grounding (bonding) surrounded by a flexible plastic jacket".

The sheathing is colour-coded:
white=typical lighting circuit, 14GA wire, white+black+ground
white=3-way light circuit, 14GA, white+black+red+ground
yellow=kitchen appliances, 12GA wire, white+black+ground
red=240V heaters, 12GA wire, red+black+ground
orange, blue, etc etc

My home is circa 1968 so most of the original cabing is not colour-coded and the sheathing is not thermoplastic but a woven fiber casing (dark green or blue) around a paper wrapping. However, the cable's conductors are insulated with a thermoplastic and are typically white (Neutral) and black (Hot) plus an uninsulated ground wire.

Could you describe your cabling in greater detail please?

Ooops sorry for typo. At my home, the electrical wire for the lighting do not has ground. Inside the box I can only find incoming hot and switched hot. So I need to trace and fish for a neutral wire from light fixture. I think the two 'N' poles of X10 wall switch are common, no need to pick out incoming neutral and outgoing neutral.

 

[AO-Brandon]

Now that right there is just scary. Is that what you pulled directly out of the wall? No sheath or anything?!

 

[mustangcoupe]

kinman,

I looked in your profile but it is not listed, where do you live? That wiring sounds real "interesting"...

 

[AO-Brandon]

okay, new theory:

You have concrete walls with conduit. There is no sheath required in conduit and that twist looks awfully familiar.

Your builder ran BX inside the wall, and that is what you pulled that out of.

That twist looks exactly like what is found in BX. Am i correct?