Quick (and probably dumb) question about wiring a new overhead light & switch with new wire........

[vyacheslav]

Greetings. I just wanted to double check myself.

I am running a new overhead light fixture with new Romex wire, with a switch that will control that overhead, also with new Romex wire. I don't need to have both pieces of Romex (from the fixture and from the power source) into the same light switch box, as long as they are connected together elsewhere with power, correct? Here is my layout:

1. Romex wire coming from the overhead light fixture, down into my basement ceiling into a junction box.
2. Romex wire coming from the switch that controls the overhead light fixture into the same junction box as above
3. Romex wire coming from the circuit breaker panel that supplies power, into the same junction box as above.

As long as the switch Romex and the fixture Romex are connected together from the same power source on the same circuit, that's all that matter right? In other words, I would only need one piece of Romex (the switch Romex) going into the switch box and connected to the switch itself? Theoretically, I could have the fixture Romex and the switch Romex running into the basement 50 feet apart if I wanted, as long as they are in the same junction box/getting power from the same source, right?

Also, these are the only items in that junction box, so it's not like the switch will be controlling other items in the junction box, it's just those three pieces of Romex (fixture, switch, power). Just out of curiosity though, what if there were other items in that same junction box that I didn't want the switch to control? How would I arrange that?

Thanks for your help and reassurance on this!

V

 

[bud16415]

You want the switch to switch the power in the hot leg of the light circuit (Black). It could be wired and work switching the neutral/common (White) but that would turn the light on and off but leave a hot in the fixture even when the light was off and would be a possible problem when changing lamps.



So what you are talking about is you would make both the black and white hot wires going to the switch the power would go out the black thru the switch and back the white and connect to the black going out to the light. The white from the light would connect to the white of the incoming feed. Because you have a white connected to a black and you are using the white as the power wire most people will color that wire black or wrap it in black tape at the end to show it is a black power wire.

If you need other full time power from that feed you just connect them in at the black and white feeds wire nuts.

 

[afjes_2016]

Maybe because I am only on my first cup of coffee so far this morning but it seems from your description you are basically running a switch loop from the junction box to the switch box. This will work in theory but I would advise you to run three wire with ground from the junction box to the switch box since neutrals are required at all switch boxes now. You would just cap off the neutral wire in the switch box. The neutral wire is required by code now for new electronic switches such as wifi etc that require neutral wires.

You always want to create the switch so that the hot is controlled by the switch and not the neutral.

If I am off base with this someone let me know - still a bit asleep this morning

P.S.
vyacheslav
Also there are no such thing here in this forum as a dumb question. We are here to help the DIY. It is good that people ask questions to be sure of proper installation for safety both personal and material.

 

[bud16415]

Great point and I learned something today about needing a neutral for an electronic switch.

I don’t see myself putting any in soon, but I know people are doing this more. I got two electronic wifi outlets for Christmas last year from my nephew and I still don’t know of anything I want to turn on and off from my phone. The year before he gave me an electronic light bulb that I can change the color of the light from my phone. I made it a night-light in the up-lighting but now it is stuck on a green I don’t like.

 

[tomtheelder2020]

Vyacheslav, the configuration Bud describes is exactly the original wiring for a light in the garage of my 70 y.o. house. It was just dumb luck that I did not kill myself when I reconfigured the wiring. That was 30 years ago and since then I never work on wiring without turning off the circuit but the next person working on your system might not.

 

[bud16415]

Vyacheslav, the configuration Bud describes is exactly the original wiring for a light in the garage of my 70 y.o. house. It was just dumb luck that I did not kill myself when I reconfigured the wiring. That was 30 years ago and since then I never work on wiring without turning off the circuit but the next person working on your system might not.

Along with not trusting the switch on a simple light circuit to kill the power it is also important to connect the hot leg to the connection that goes to the center of the bulb or the center of the bulb holder and not the brass screw sides of the holder. When people unscrew a bulb most people just touch the glass but if your finger slides down the neck and the brass base of the bulb were to be touched as it was partly out you could get shocked if the power was to that side. Most light fixtures have a black and white wire for connecting some don’t and some have screw connectors.

There is no better tool to have than a multi-meter if you are playing around with electricity. It only takes a second even when you kill the power to check and make sure it is off. Pros use them and IMO it is even more important DIYers do also.

 

[vyacheslav]

Thanks for your help everyone! Also, in addition to the multimeter, I also have a non-contact voltage detector. Safety is always the first priority!

 

[afjes_2016]

Bud16415

Along with not trusting the switch on a simple light circuit to kill the power

Yes Bud I agree with you - this is very true and one thing that many DIYers don't know. Meaning - they want to replace a ceiling light fixture so they assume that if you flip the light switch off then there is no power at the light fixture box. We know that the power can originate from the light fixture box down to the switch as a switch loop so even though the light switch is turned to the "off" position there is still power to the light fixture box.

It is always best as we know to verify which circuit your project involves and then shut that breaker, disconnect etc off, then verify that the power is off to that circuit before starting any work on the circuit.

The instructors in my "electrical classes" always stressed to us "Don't be afraid of electricity - understand it - and then respect it!". This is even good advise for DIYers.

 

[bud16415]

Bud16415

Yes Bud I agree with you - this is very true and one thing that many DIYers don't know. Meaning - they want to replace a ceiling light fixture so they assume that if you flip the light switch off then there is no power at the light fixture box. We know that the power can originate from the light fixture box down to the switch as a switch loop so even though the light switch is turned to the "off" position there is still power to the light fixture box.

It is always best as we know to verify which circuit your project involves and then shut that breaker, disconnect etc off, then verify that the power is off to that circuit before starting any work on the circuit.

The instructors in my "electrical classes" always stressed to us "Don't be afraid of electricity - understand it - and then respect it!". This is even good advise for DIYers.

One thing I have never figured out and to the best of my knowledge code doesn’t do a good job of addressing is labeling the power panel. I have seen a few that everything perfectly labeled. Most have a few chicken scratching and some have nothing. With breakers covering multi rooms with breaking up circuits and such you really need a map/floor plan where next to each place electric come to the surface a number next to it telling the homeowner the breaker number.



How many times I have done the radio thing or the second person yelling down the stairs or on the cell phone. Or worse me running up and down some stairs 10 times.

Does code spell out labeling a box?

 

[afjes_2016]

Yes, Bud a floor plan is in my opinion the best way. Even in my home I created a simple floor plan, marked where all receptacles, light, outlets etc are in the living space, basement and attic.
Then went thru the task of identifying all the circuits in the panel and marked on the floor plan next to each receptacle etc the breaker #.

If I did any major renovations - first thing I would do is a circuit floor plan.
The time I spend doing that saved many many hours.