Installing my 1st switch - baffled by odd wiring

Other Devices & Integrations Lighting & Load Control
#1

Hey folks… I just got my Veralite this week and today I’m trying to install my first simple 2-way switch. I’ve replaced switches in various homes through the years, but this one strikes me as very odd.

I’m attaching a photo since that may describe the situation best.

This switch controls a single recessed light in a part of the house that’s probably around 60 years old. Not too surprising, the switch is not grounded, and there’s not a ground visible in the box. It looks like I have a white and black wire coming from the panel to this box, and then a white, black and red going to the fixture. That surprised me a bit since it’s not a 3-way, so I wouldn’t expect to see a traveler in the box. The light does happen to be near the top of my basement stairs, so maybe someone planned for a 3-way but went another route.

The current wiring:

  • whites (likely neutral) are tied together directly from source to load side.
  • blacks are tied together and connect to one pole of the existing 2-way switch
  • red is connected to the other pole of the 2-way switch.

If you see in the photo, the black wires are connected in an ugly manner which I know is bad practice (wire stripped mid-span to wrap around the switch screw). That aside though, I can’t really understand how this switch operates in its current state, or if I can replace it with an Evolve LSM-15.

Any ideas? I do have a multi-meter that I can test with a bit if need be.

Thanks!

  • Jason
#2

it looks like at one time it was part of a three way setup.

check Voltage of the red and black in the on and off position and it will tell you which is line (always hot) and load (switches)

I believe the Evolve uses a neutral, for which you will need to wire a short jumper from the neutrals (white) to the neutral

there is no ground, if it makes you feel good, you can ground the switch to the box.

it is not that ugly… I’ve seen worse

#3

Thanks for the advice and encouragement. You’re right - it’s not that bad, and I think the multimeter helped solve the minor mystery.

I’ve confirmed that the “right” side black and white wires are indeed the supply side line and neutral respectively. The rest of the situation became clear when I noticed that a separate 3-way light for my basement stairs turned off as soon as I removed the wire-nut from either the hot or neutral wires. So the “left” side hot and neutral continues on to supply power to another switch. The red wire is the switched hot to the light in question.

So with that in mind…
LSM-15:
Black wire connects to line, just as the existing switch (allowing the ‘hot’ to continue to other switches, outlets, etc)
Blue wire connects to the existing Red wire, supplying power to the fixture when outlet is on
White wire connects into the existing wire-nut with the neutral supply and load(s)

That seems almost too easy. At least it won’t be too hard to add a proper ground down the road given the proximity to plumbing. I’m going to give it a try as above and see how it goes.

Thanks again,
Jason

Update: It works and I didn’t kill myself. Of course I can’t get the wires and switch to fit into the box, but now I’ll go shorten the wires on the new switch.

#4

It appears that there is a ground. It looks like it is connected to the exterior of the gang box.

Use your multimeter and test for voltage from line to the box, I suspect you’ll see that the box is grounded.

You can also use the Ohm meter and test for continuity from neutral to the box(ground). If it indicates continuity, the box is grounded.

Make sure that you don’t test for continuity to the line. That lets the smoke out of the multimeter and once you run out of smoke it stops working.

#5

alway good when a newbie makes it through…

you are here to stay!

yes, cramming those wires in this old boxes is sometimes a hassle.

#6

Next post; why is my signal so weak and unreliable? ;D

#7

[quote=“Z-Waver, post:4, topic:180299”]It appears that there is a ground. It looks like it is connected to the exterior of the gang box.

Use your multimeter and test for voltage from line to the box, I suspect you’ll see that the box is grounded.

You can also use the Ohm meter and test for continuity from neutral to the box(ground). If it indicates continuity, the box is grounded.

Make sure that you don’t test for continuity to the line. That lets the smoke out of the multimeter and once you run out of smoke it stops working.[/quote]

I don’t advise doing an ohm test from ground to neutral at a wall box. Yes, they are suppose to be joined together at the main panel, but there are instances where one has a bad neutral branch which causes a stray voltage to develope at the neutral wire at the wall box.

#8

That’s a fair statement. And I can see people getting into trouble with n-way wiring.

All the same, continuity tests should be done with the circuit de-energized(breaker off). If it still lets the smoke out, with the breaker off, then you need a new meter and to fix the wiring.

#9

Thanks again for the assistance. The wiring of this outlet is not as weird as I thought. The line just passes through this box to supply power to more than one circuit. Once testing that became obvious and the rest has been a snap.

I’ve since added several more switches and sensors, so the range and reliability quickly became excellent.