How do you add a separate fixture along with a separate switch from an existing switch which has only 2 hot wires coming from the wall that are attached to the 1st switch?

Answer for USA, Canada and countries running a 60 Hz supply service.

Most times you can't feed your load only from the switch because it doesn't have a neutral.

If there are no existing power outlet branch circuits nearby you'd have to consider connecting into the existing light fixture, which is where the hot feed and neutral wires should be.

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If you are lucky - and by lucky I mean the cable to the switch isn't stapled in the wall (which is very unlikely) - you can use the old cable to pull through a new piece of 14-3 cable to get the neutral in the box that you will need to be able to power a new switched outlet.

A new cable is needed because, as well as the "unswitched hot" and the "switched-hot return" to the light fixture, the box must have a full power service including Hot (Black), Neutral (White) and Ground (Bare Wire).

However, to do this job safely, there are several things you must first check:

  • Do your local wiring codes allow you to fit a new socket outlet in the intended place?
  • Is the breaker protecting the lighting circuit not already overloaded by its existing lights and any extra outlets that are already in place?
  • Will the load to be applied to the new outlet be no more than 5 amps?

    Even if the new outlet is to be the normal 15 amp size, a higher load current (amperage) than 5 amps could dangerously overload the existing wire size of the lighting circuit.

    Such overloading is a common cause of house fires!

Do the following:

1. Turn off the breaker controlling the switch.

2. Remove the switch from the box.

3. Identify the supply Hot Black Wire (Call it B1)

4. Remove B1 from switch and label in some way so you'll remember what it is.

5. Undo the wirenut in the box which will typically have two white wires unless the box is also being used as a junction box and there may be more than 2 white wires.

6. Get a piece of the same gauge white wire long enough to reach the new outlet to make a new pigtail - strip about 3/4 in from each end - and add it to the bundle of white wires connected together. (You may need a bigger wire nut.) Make sure that all wires are solidly connected.

7. Make two black wire pigtails long enough to reach the new switch and outlet and connect one end of one of them to wire B1 using a wirenut.

8. Connect that black wire pigtail to one terminal of the new switch and the other black wire pigtail to the terminal on the outlet that has a brass-colored screw.

9. Connect the new white wire pigtail to the terminal with the silver-colored screw on the outlet.

10. Connect the black wire from the new outlet to the terminal on the other side of the new switch.

11. Make a new ground pigtail and connect it from the bare wire in the box to the green screw on the new outlet.

Warnings

Make sure all connections are tight and no bare wires are exposed.

Make sure you have identified the supply B1 wire correctly. If not you will create a switched outlet as well as whatever you were switching before.

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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances,

always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.