Questions about disconnected wires and low voltage in a switch.

4 years ago

I have a few questions about a light switch in my basement. The switch is working (toggles light).

The AC Voltage across the top and bottom screws in the blue area of the switch is 4-5 Volts. Is that supposed to be this low? (I expected 120V)

Also, I see that black wires are connected to the switch, and white wires are presumably connected and covered with black electrical tape. Should I leave them as-is or is it better to use a twist-on wire connector?

There are also two black wires at the bottom of the electrical box, which are not connected to anything. Should they be connected to anything?

Sort by:Oldest

Comments (5)

Ron Natalie
4 years ago
When the switch is "on" the voltage should be pretty close to zero. When the switch is off, you might read something closer to 120V. Odd small voltages probably indicate that you're reading phantom induced voltages. You meter has a very high input impedance.

Twisting the wires together and taping them is ***NOT*** a legal way to connect things. If there's not a proper fastener under all that tape, yes put a wire nut on it. MAKE SURE YOU TURN OFF THE BREAKER FIRST.

As for the two cut off wires, they probably were connected to something that has been removed. Hopefully, they don't have voltage on them because even though they're not stripped, it's still possible that the tips could touch or arc against the metal box or other conductive stuff in the box. I'd cap them off with a wire nut or something just to avoid problems.

This whole thing reeks of some previous harry homeowner doing some DIY work. You may want to have someone with a clue take a look at things just to make sure it is right. It's not possible to tell by looking at a photograph.
kudzu9
4 years ago
If that were my house, I'd hire an electrician to check out everything. With that many wonky things in one box, my money is on numerous code violations elsewhere that raise the issue of shock and fire hazards.
Related Discussions
Low-voltage recessed wiring questions
Q
Comments (2)
You've entered into the often misunderstood world of low voltage power wiring. Basically you have to treat the wiring just like 120V wiring with junction boxes UNLESS you use class 2 power limited transformers. This is what is required with typical low voltage puck light installation. Wiring must still be in wall rated to pass though the structure. Not all combinations of low voltage lighting installation parts by manufacturers are UL listed (and some will tell you that)so it is possible that you can't even connect what you have been given in a code approved way. For these parts to be compatible the transformer will have five 5 amp fuses or circuit breakers on it, each meant to supply up to 60 watts of lighting. So each fixture will have it's own run of cable back to its own connection point on the transformer. It's OK to lengthen runs using the manufacturer's voltage drop table and recommended wire size.
...See More
Low Voltage Linear UC Lighting System Questions
Q
Comments (2)
Be aware if you have granite and it has a shine to it. The colour of the fixtures will show up on reflextion. So if you get the white then it will show up white. We got the halogen since it came in black and we had them stain under the cabs the dark color of the cabs to hopefully minimixze the relection. I will tell you next week how it turned out......
...See More
lamp wire or low voltage wire for led ucl
Q
Comments (7)
Thank you, David and brickeyee! I know I can always count on your expertise. I have another question: Leviton magnetic dimmers vs. lutron magnetic dimmers. There are quite a few brands of magnetic low voltage transformers listing Lutron magnetic dimmers as their approved dimmer, but not leviton magnetic dimmers. I specifically asked Juno whether their magnetic transformer works with other brands of magnetic dimmer, for example, leviton. Their answer is "Unfortunately, at this time, we do not have any Leviton dimmers approved for use with the magnetic TL575 driver. " So basically no information there. I can see leviton is not listed myself! One of things I learn from this forum is that a magnetic dimmer should work with a magnetic transformer. Any reason why I shouldn't use a Leviton magnetic dimmer with a Juno magnetic transformer? Lutron is much more expensive than Leviton, what I am trading off by using a less expensive leviton? I am going to post this as a sperate posting just in case you don't see this.
...See More
Low Voltage U/C Wiring Help (also posted in Lighting)
Q
Comments (4)
The issue that quickly shows up with using NM for lov voltage wiring is the sometimes very high currents required by low voltage lighting. The wire size is based on current, with voltage playing no part (voltage determine insulation thickness). A 20 watt bulb in 120 V pulls ~0.167 amps. On 12 V a 20 W bulb pulls ~1.667 amps, and the lower voltage puts a premium on voltage drop. Dropping 1 V in a 120 V circuit is less than 0.83%, while in a 12 V circuit it is 8% and will result in noticeable color shifts (red tint) if a lower drop lights is nearby. To control voltage drops wire size may need to be increased evrn further (there are online tools that will compute voltage drop given current, wire size, and conductor length). Wire size directly affects box fill calculations and bending space. Larger conductors are often stranded to make working with them easier. The larger wires also require larger wire nuts, and may not even fit under screw heads on switches. I use small electronic 'transformers' (actually small power supplies) to power low voltage under-cabinet lights and avoid using a single large physical transformer. A 30 W power supply is less than 3 inches long x 2 inches wide and 1.5 inches thick *(most are closer to 1 inch thick). They are available for plug or hard wire connection and can use conventional 120 V dimmers. The 120 V wire can be as small as #14 (15 amp circuit) and is not hard to work with. The small power supplies can be mounted under the cabinets near the back with the lights near the front. The only complaint I have about the power supplies is they need a small strap to hold them in place (the single screw and double face tape fails pretty quickly).
...See More
Dennis Matveyev
Original Author
4 years ago
last modified: 4 years ago
Thanks. I guess I'll have to do that. My house was built in 1964 and I'm amazed to find some really wonky things. I can't imagine it was all done by previous homeowners, someone had to do something right when the house was constructed, but no?. Examples include sump pump on the same circuit as garden lights, garden fountain, and all sunroom switches. Or all kitchen appliances and sockets, adjacent room switches, outdoor light, basement light all on the same circuit. There were other wonky things like phantom disconnected wires, etc.
kudzu9
4 years ago
last modified: 4 years ago
Dennis-

in my experience houses are generally wired properly by licensed electricians when they are built. But after 50-60 years of ownership and modifications by inept homeowners one can find a lot of wonky things.
DavidR
4 years ago
last modified: 4 years ago
It's amazing what ignorant and careless people will do to wiring. If you look around, you'll find websites with photos and descriptions of some eyebrow-raising hack jobs that the pros have found. They're pretty entertaining.

In my own houses, some of the choice examples I've run into include twist-and-tape flying splices inside walls, parts of circuits wired with SJ rubber cord, NM nailed to baseboards through its middle, knob and tube run through holes in cold air return ducts with no protection, and NM laid on the ground to power outbuildings. You can't make this kind of stuff up.

Questions about disconnected wires and low voltage in a switch.

Comments (5)

Ron Natalie

kudzu9

Related Discussions

Dennis Matveyev
Original Author

kudzu9

DavidR

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Questions about disconnected wires and low voltage in a switch.

Comments (5)

Ron Natalie

kudzu9

Related Discussions

Dennis MatveyevOriginal Author

kudzu9

DavidR

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Dennis Matveyev
Original Author