Another LZW31 3-way question--old house

Don’t take this the wrong way, but both of you are jumping down rabbit holes. IMO, the box with the old dimmer DOES NOT have a constant hot. As I mentioned before, you have to find the source of the constant hot and start with that. I’m guessing that either the other box or the light has the constant hot.

The reason that the dimmer comes on when when you throw the other switch is because it’s sending the hot over a traveler, which is probably wired to the line terminal on the Inovelli.

OP, you have to find the location of where hot comes into the run. I don’t think that is the box you are trying to put the switch in. IMO, BOTH of those 2-wires are being used in lieu of a 3-wire. That’s why the one white wire isn’t connected to anything.

@Bry

Don’t take this the wrong way,

Never, it is always helpful to have another set of eyes on a problem :slight_smile:

I’m willing to rethink the wiring, especially since it’s not a typical configuration.

OP, you have to find the location of where hot comes into the run. I don’t think that is the box you are trying to put the switch in. IMO, BOTH of those 2-wires are being used in lieu of a 3-wire. That’s why the one white wire isn’t connected to anything.

I agree it would be nice but I’m of the mind there is both these boxes are missing either hot or neutral.

I think wires A and E are either:

  1. between the load and neutral
  2. between the line and the load

In either case we are missing one of the two wires we would like to have.

@kbrackley

Okay, breaker off. I have an old Micronta 22-212 in ohms mode, and the meter doesn’t budge a bit. The meter is working because I can touch two places on the box itself and it registers.

I should have asked to perform the same measurement on the G wire. If that is neutral and power is coming in on wire E then we could be in luck.

John

I think you may be correct, as I’ve been thinking the same thing. That means power is going to the light first, which AFAIK means the Inovelli won’t work. You’d have to use another brand that only requires one traveler so you can steal the other to route the hot to the primary box.

There is still hope the unconnected wire in the other box is a neutral…lets hope.

John

My money is on that is the other end of the unconnected white in the dimmer box. It’s not conventional, but if you don’t have 3-wire Romex, you can use two 2-wires. You only need three conductors, so the 4th one is unused.

Lets hope your right :slight_smile:

So I need to test to see if I get anything on the ohm meter on the “G” wire (white wire in the dumb switch box)?

Yes when measuring from the white wire to the metal box.

Also something has been bothering me. Can you tell if the incoming cables are Romex (plastic jacket) or BX/MX which have a metal spiral jacket ?
It would be a shame if the white wire(s) were actually neutral but the box isn’t grounded.

John

Okay, sorry for the delay–it got dark and noone here to hold the flashlight!

The “G” wire, white solo doesn’t register a thing (power off, ohm mode, touching the white and the side of the electrical box).

I cannot see beyond the electrical box, all that I can see is a bunch of paper wrapper around the two wires. I have two sets of those as mentioned, each with a black and white rubber/plastic copper wire.

Its tough to see, especially when your not familiar with the hardware.

To summarize:

  1. You’ve found the wiring between the two switches consists of travelers but no Hot or Neutral

  2. Each box has a white wire that one would assume is Neutral but measurement to the metal box are “opens” and not able to verify the white are neutrals.

  3. You said earlier “…So I have learned that my house is wired with 2-wire Romex without a ground…”

  4. By looking in the box you were not able to see whether the cable is Romex or metal.

  5. It would be great if D and or G were neutrals as then the Inovelli will work fine.

I’m likely being over conservative here but I don’t want to take a step unless we are sure of the situation.

I would suggest:
With your trusty Micronta 22-212 measure AC voltage between:
A and D = ______
E and G = ______

If one or both readings is ~120V then we are 90% sure the white(s) are neutral.

John

Green, clamp for Romex (plastic jacket)

Red, clamp for metal jacket cable
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