I have a single pole light in my hall way and want to add a recess light with its own dimmer switch next to the existing light switch

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    Whether you can add a light from the existing switch box depends on whether you have a neutral in the existing box. You may or may not have one. If there is only one cable in the switch box (with a black wire on one side of the switch and a white wire on the other side), the white would be be a "switched hot" and would not be a neutral. To get power to another light one needs a hot and a neutral. – Jim Stewart Jun 22 '18 at 2:51
  • no it has neutral cause the switch has two black wires hook to it and like 3white wires togeter – Robert benavides Jun 22 '18 at 2:54
  • Assume the three white wires are neutrals. One of the black wires on the switch will be line hot (always hot) and the other will be switched hot to the existing light. With a multi meter or voltage tester determine which is the line hot. I think you will want to replace the existing 1-gang box with a 2-gang box for the additional dimmer switch. This will also give more room for wires. – Jim Stewart Jun 22 '18 at 9:58
  • Are the exact, detailed steps clear to you? Is this existing circuit a 15 A circuit? I am behind the times, it appears there are double dimmer switches for a single gang box. The only problem might be enough room in the box for all the wires and connections, i.e., so called box fill limitation. prolighting.com/… – Jim Stewart Jun 22 '18 at 15:48
  • @Robertbenavides - When everyone is talking about modern or new wiring, that would be a dwelling that fell into the 2011 NEC. That was when it was made part of the code. Other than that the neutral would have to be in the box for a reason. – Retired Master Electrician Jun 22 '18 at 21:07

If your wiring is very modern, a neutral wire will be present at the switch box, and adding a new circuit that draws its power at that switch is possible and simple.

If your wiring is not modern enough to have a neutral wire will be present at every switch box, but your circuit is wired with power coming from the service panel to the switch first, then adding a new circuit that draws its power at that switch is possible and simple.

But - if your wiring is not modern, and your circuit is wired with power coming from the service panel to the light first, then there is no neutral path available at the switch, and adding a new circuit is problematical. You will have to draw power for the new circuit from somewhere else.

I don't know how to be completely confident that there is a neutral wire in the switch box, but if there is only one cable entering the box, and the two insulated wires of that cable connect to the two terminals on the switch, then there is no neutral present.

The neutral wire in a switch box usually appears as the white wires from two or more cables connected together, typically with a wire nut. If you have many wire nuts in the box, then the situation is more complex, but one of the wire nuts will be bundle of neutral wires.

Before you modify any electrical wiring, you must know what each existing wire is for and what it is connected to. Do not under any circumstances just start hooking things up to see what works. It is easy to create a circuit that seems to work properly but is in fact a deadly hazard.

  • It just depends on if the switch location is the feed or the light, not how modern it is. See Jim Stewart's comment. – Ed Beal Jun 22 '18 at 9:25
  • @Ed Beal: Modern wiring will follow the new NEC requirement that a neutral path be provided in all switch junction boxes. – A. I. Breveleri Jun 22 '18 at 12:06

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