Add combo (switch and outlet) with only two wires out of wall for the current light)

Question

I probably have this diagram for my project. Or problem.

Facts:

a) only 2 wires out of wall, B & W;

b) switch ON, lights ON

Ceiling electrical box:

One black and one white connects to the ceiling light fixture.

Project: I need to add a combo switch/outlet

UPDATE after suggestions

Grey= Neutral Is this right? If it is, it seems to me receptacle will be ON at all times, right?

Answer 1

Three options

Run a new /3 cable

You either replace the existing cable with /3 cable (which is now required in new work), in which case your three wires are:

• always-hot (traditionally black, often white-with-black-tape, sometimes white)
• switched-hot (ideally red, sometimes black, often white-black-tape, often white)
• neutral (always white)

And these three go to the lamp/receptacle combo, always-hot to the common bar, switched-hot to the switch side, and neutral to the receptacle side.

Run a whole separate /2 cable

In a perfect world you source that from another location which is not a lighting circuit, but does provide GFCI, AFCI or whatever other protection you need owing to that location. But if you need to, you can get this from the lighting box, if Code allows this, e.g. In bathrooms it might not. In this case your two new wires are:

• always-hot (black usually)
• neutral (always white)

And you break the tab off the hot side of the switch/recep combo. These two new wires go to the receptacle side, neutral to the taller pin side. The two existing wires go to the switch side only. You must break off the tab.

Smart switches

Talking something like Insteon.

In this case, rewire so all black wires are always-hot, and all white wires are in fact neutral. Always-hot and neutral go to your smart switch w/ receptacle.

Up in the lamp, the switched-hot to the lamp is now dangling, as it has nowhere to connect to, there are no switched-hot wires up there, you killed them.

So you get a smart-switch module, that connects to always-hot and neutral. It also has a "Load" line which goes to switched-hot, and that's where the lamp's switched-hot wire goes.

Now if you leave the light on, you can turn it off with your phone. From Kazakhstan.

Answer 2

Your first diagram shows a switch loop.

Neutral and hot wires arrive at the light box, the neutral stays in that box, while only the hot is sent to the switch box (customary using white with black marking), and returns with the (customary) black wire, which is now a "switched hot".

If you want an outlet at the switch box, you need to bring a neutral from the light box. A customary way would be to wire a 14/3 or 12/3 from the light box to the switch box: - white neutral - black hot - red switched hot (returns from the switch and connects to the light fixture black).

You can then decide wether you want this outlet to be always hot, or if you want the outlet to be switched.

The wire gauge depends on the breaker size. 15A breaker requires 14 gauge or bigger. 20A breaker requires 12 gouger bigger.

Answer 3

This set up worked well. The bridge (wall receptacle/switch) on the right side (two black screws) intact. The plug is ON at all times. The light works as expected. I wanted the switch to control the receptacle but didn't manage to do it.

Ceiling light box had 2 sets of wires: B and W from the wall switch/plug. It does require extra wire. So 12/3 (or 14) needs to be added. 2 wires will NOT work.
Ceiling box: B hot and W were there.

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