Thanks for all the replies... I think I am getting a much better idea of how these switches work. What if I connect the UPB neutral lead to the load lead. Would this not serve the same purpose as the 2 wire Z-Wave/X10 switch? Or does it need the neutral to send UPB signals and the path through the lights would affect the signal.
Need some guidance
- Thread starter tyroiii
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rocco
Active Member
Hey, elcano, your right. I completely overlooked the fact that the switch's neutral does not pass any load current.elcano said:
Never mind . . .
Yep, you hit my head with a nail. The neutral is needed to transmit UPB messages, and the load would have too high an impedance and obstruct the signal. I don't know the output impedance of UPB, but Insteon has an output impedance of only 5 ohms, and I believe UPB would be even less. A 60 watt light bulb would have an impedance around 240 ohms.by tyroiii said:
I guess I can just try this to see if it works. Let's say that I have recessed lighting and the load wire are wired to the lights in parallel, would the UPB signal travel the road of least resistance and not go through any of the lights?rocco said:
Unless there is a major safety issue, I'm going to give this a try tonight when I get home
Steve
Senior Member
Let me give you a bit more info on what I did this to...
The jbox without the neutral had 2 switches, 1 for a single light and the other for a 3 way switch that connected to a string o 6 recessed lights each with a 75W Halogen bulb. When I install recessed cans I usually go from line to switch and then from can to can to can in a string. Since these were the builders, I looked up in the attic and couldn't make heads or tails of it. Some can had 1 wire, some 2 and some 3. The electricians probably used them as junction boxes or something. Anyway, I ran a piece of romex from the outlet (on a separate circuit) to the jbox with the 2 switches. The box already had a ground so I snipped the ground and black wire in the new sheath, leaving only the white for neutral. I connected the neutral to the outlet below and used it for the switch in the box above. The line and travellers got hooked up as normally along with the ground.
Everything works fine with both this switch (the master) and the slave in another box except for the fact that it does not respond to all on or all off - a separate issue. I think you will be fine with this approach.
The jbox without the neutral had 2 switches, 1 for a single light and the other for a 3 way switch that connected to a string o 6 recessed lights each with a 75W Halogen bulb. When I install recessed cans I usually go from line to switch and then from can to can to can in a string. Since these were the builders, I looked up in the attic and couldn't make heads or tails of it. Some can had 1 wire, some 2 and some 3. The electricians probably used them as junction boxes or something. Anyway, I ran a piece of romex from the outlet (on a separate circuit) to the jbox with the 2 switches. The box already had a ground so I snipped the ground and black wire in the new sheath, leaving only the white for neutral. I connected the neutral to the outlet below and used it for the switch in the box above. The line and travellers got hooked up as normally along with the ground.
Everything works fine with both this switch (the master) and the slave in another box except for the fact that it does not respond to all on or all off - a separate issue. I think you will be fine with this approach.
Without making a recommendation on the subject, I've heard that in limited circumstances, one can sometimes get away with connecting the switch's neutral to ground. Providing it is not a load bearing neutral of course.
Pros:
* It supposedly works.
* It is supposedly relatively low risk because the neutral from the switches is such a low current and is purely used for signalling and powering the switch electronics.
Cons:
* I'd be highly suprised if it wasn't illegal/against code.
* You'd be putting a trickle current into wiring that is reserved for a safety system.
* A real electrical fault that uses ground to conduct away voltage would put your switches in the line of fire.
* It'd almost certainly trip a CFCI if there was one on the circuit.
* If you ever had a house or electrical fire, even because of something unrelated to this, you can bet the investigators will find it. You might find insurance refusing to pay, or even worse. (If you were an insurer, would you pay up if there was a convenient scapegoat to blame/cast doubt apon?)
* If you left it this way in a house and sold it later without fixing/removing it and somebody was shocked or something damaged, you could expect to get sued.
In other words, there are some serious downsides to consider.
The reason it should work is that ground and neutral are both at earth potential and go to ground rods. However, neutral is designed for carrying load, ground is a safety system.
I have never done this so I don't know myself. I've always been able to get neutral without having to tear up walls. I never wanted to risk trying this.
I've heard rumors that some companies that sell switches will sometimes hint that this is possible and warn about the risks. But never in writing, only on the phone.
-Peter
Pros:
* It supposedly works.
* It is supposedly relatively low risk because the neutral from the switches is such a low current and is purely used for signalling and powering the switch electronics.
Cons:
* I'd be highly suprised if it wasn't illegal/against code.
* You'd be putting a trickle current into wiring that is reserved for a safety system.
* A real electrical fault that uses ground to conduct away voltage would put your switches in the line of fire.
* It'd almost certainly trip a CFCI if there was one on the circuit.
* If you ever had a house or electrical fire, even because of something unrelated to this, you can bet the investigators will find it. You might find insurance refusing to pay, or even worse. (If you were an insurer, would you pay up if there was a convenient scapegoat to blame/cast doubt apon?)
* If you left it this way in a house and sold it later without fixing/removing it and somebody was shocked or something damaged, you could expect to get sued.
In other words, there are some serious downsides to consider.
The reason it should work is that ground and neutral are both at earth potential and go to ground rods. However, neutral is designed for carrying load, ground is a safety system.
I have never done this so I don't know myself. I've always been able to get neutral without having to tear up walls. I never wanted to risk trying this.
I've heard rumors that some companies that sell switches will sometimes hint that this is possible and warn about the risks. But never in writing, only on the phone.
-Peter
upstatemike
Senior Member
Interestingly Leviton ODS10-IDW motion sensors use ground instead of neutral and are UL listed!
Here's an update from my test yesterday.
I connected the neutral to the load lead and that results in interesting lighting fireworks... Apparently there's enough electricity travelling through the bulbs. When I connected the neutral to ground, everything worked fine. I guess the big question is, is this safe or wise.
I connected the neutral to the load lead and that results in interesting lighting fireworks... Apparently there's enough electricity travelling through the bulbs. When I connected the neutral to ground, everything worked fine. I guess the big question is, is this safe or wise.
Steve
Senior Member
Woah, I hope that is a typo! Don't want to connect neutral to load... Connect the line in to line on switch, the load to the load wire on switch, ideally the neutral to a neutral you pull and ground to ground.
You can attach the neutral on switch to ground but it is really not kosher. It is much better to pull a neutral from the outlet, even if from a different circuit.
You can attach the neutral on switch to ground but it is really not kosher. It is much better to pull a neutral from the outlet, even if from a different circuit.
Steve
Senior Member
Wow, I just had a shocking experience :unsure:
I am working on an in wall touch screen (which is another story for later), and was going to pull power from an outlet below. I believe that outlet is on the same circuit as the outlet where I ran the neutral to the switch that was missing it.
Well, I shut power to the outlet I was working on, and confirmed with a meter it was off. So I pull the outlet out and start disconnecting the wires. I was disconnecting a neutral and BAM, a nice little bite. At the same time the kitchen lights dimmed and came back on. I was totally baffled but my 'buzzing a/c detector' does pick up slight current on the neutral line! If I turn off the kitchen lights the buzz stops.
It must be that with the light on there is some current going through that neutral! Wow, tough way to learn that lesson. Guess I need to turn off kitchen light circuit too. Just weird cause I never got bit from a neutral line before!
So I guess there is a danger to pulling a neutral from another circuit after all. But I guess it is ok as long as I am not messing with that circuit.
I am working on an in wall touch screen (which is another story for later), and was going to pull power from an outlet below. I believe that outlet is on the same circuit as the outlet where I ran the neutral to the switch that was missing it.
Well, I shut power to the outlet I was working on, and confirmed with a meter it was off. So I pull the outlet out and start disconnecting the wires. I was disconnecting a neutral and BAM, a nice little bite. At the same time the kitchen lights dimmed and came back on. I was totally baffled but my 'buzzing a/c detector' does pick up slight current on the neutral line! If I turn off the kitchen lights the buzz stops.
It must be that with the light on there is some current going through that neutral! Wow, tough way to learn that lesson. Guess I need to turn off kitchen light circuit too. Just weird cause I never got bit from a neutral line before!
So I guess there is a danger to pulling a neutral from another circuit after all. But I guess it is ok as long as I am not messing with that circuit.
BraveSirRobbin
Moderator
I'm going off of my memory from a few years ago (read that as "scarey") but what happens is that in the kitchen sometimes a neutral wire is shared with a 220 line. When you lift the neutral from another nearby outlet you loose it's reference and you can get 120 volts between it and ground.Steve said:Wow, I just had a shocking experience
I am working on an in wall touch screen (which is another story for later), and was going to pull power from an outlet below. I believe that outlet is on the same circuit as the outlet where I ran the neutral to the switch that was missing it.
Well, I shut power to the outlet I was working on, and confirmed with a meter it was off. So I pull the outlet out and start disconnecting the wires. I was disconnecting a neutral and BAM, a nice little bite. At the same time the kitchen lights dimmed and came back on. I was totally baffled but my 'buzzing a/c detector' does pick up slight current on the neutral line! If I turn off the kitchen lights the buzz stops.
It must be that with the light on there is some current going through that neutral! Wow, tough way to learn that lesson. Guess I need to turn off kitchen light circuit too. Just weird cause I never got bit from a neutral line before!
So I guess there is a danger to pulling a neutral from another circuit after all. But I guess it is ok as long as I am not messing with that circuit.
If you turned the breakers off to the nearby 220 volt source (range I'm guessing) you will probably find that the neutral to ground would now be zero.
I don't pretend to totally understand this as I'm like you thinking this should be against code, but this scenario actually happened to me when I was trying to put in an X-10 outlet in place of my refrigerators outlet (which is right next to my 220 volt oven/range).
Again, I may not have all the facts straight as this happened a while ago. I'm offering this information to help you troubleshoot your problem. :unsure:
Steve
Senior Member
Thanks BSR. In this case I'm sure it's the kitchen lights that I shared neutral with. The big indicator was when I got shocked the lights dimmed and came back. When I shut the light off, the slight buzz went away. I killed that circuit just to be sure and seems ok. I got it all disconnected and in process of rewiring. No 220 involvement.
BraveSirRobbin
Moderator
Ah, maybe also check that neutral and grounds are tied together in your circuit box as well.Steve said:
Good luck,
BSR
Guy Lavoie
Active Member
I still can't understand why mechanically linked circuit breakers are not mandatory when you have circuits with shared neutrals. I got nabbed once by one of those myself...and put in linked circuit breakers when I put in my new electrical panel.
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