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

1. On a 120 volt system in which the house is located in the United States, how do I wire a light switch that only has one point which will control the device?

A: (TURN OFF THE CIRCUIT FIRST) In order to wire this switch, we'll assume you are not running a completely new circuit, instead you are tapping off of a nearby receptacle or other power supply.

With Romex cable, inside the box where the switch is or will be, optimally you should have all black, all white and all copper individual wires. The neutral (white), you want to wire nut all of them together and bury them in the back of the box.

Second, you want to do the same with the grounds (complete copper or green wires) with the exception of this: You have to check what type of box it is in which the switch has been or will be placed.

1. If it is a metal box then you will need two ends (or very small pieces of same colored wire) coming out of your grounds wire nut. These are called pig tails. One end will go from wire nut to switch. The other wire end will be attached to the metal box via a green ground screw.

2. If the box is a non metal, plastic box, then everything is the same with the exception that instead of two wire ends coming from your grounds' wire nut, there will only be one end that will emerge. Take this end and screw it onto your switch itself where the dedicated ground screw is located on that switch. Usually it is a green screw on the switch itself. That's the spot where you will land the end of your ground wire.

Now that the grounded and grounding conductors (Grounds and neutrals) are finished, we are left with the task of your hot conductor and the switched leg (the screws on the switch itself are usually gold colored screws), unless your box has more than two Romex cables entering it. Then, you have to take a volt meter and determine which wire is the constant hot. In the case of the wire going toward the light, make sure if you are the one who ran the wire from switch to device, you have the black wire (switch leg) marked. If not, you have opened up a can of worms.

When multiple wires are entering a box, the most important wire to separate from all the other black wires is your switched leg. Your other black wires are (90% of the time) loads and one feed. Wire nut the feed and loads all together with a 6" pig tail coming out of your wire nut going toward one of the two screws dedicated for hot conductors. Land your feed (6"pig tail you just made) on one of these screws and your wire headed to/from your device (I have been assuming it is a light) on the other. You're done.

In summation:

Turn off the circuit which is responsible for powering the switch (or proposed switch).

Wire nut all white wires with no pig tails.

Determine if your box is metallic or plastic.

Cut one or two 6 inch pieces of wire colored green or bare copper.

Grab the (those) cut piece(s) and all the grounds in the box.

Wire nut them together where you will have one or two small pieces of wire coming from where the wire nut is at. (The wire nut that connects all your grounds.)

Land the 6" piece(s) in its (their) appropriate place(s) as described above.

Land one black wire (or hot conductor) on one of the gold screws.

Twist screw with wire underneath tightly.

Repeat the previous two steps with your other black wire remaining.

Turn on the circuit which controls the switch you were working on.

Enjoy controlling the device that prior to you working on it, had power continuously.

Please take extreme caution when working with electricity, as it can kill you. All it takes is 5 milliamp and you could die. If you feel for any reason that you or others may be hurt off of this project, then by all means contact a licensed electrician.


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.




User Avatar

Wiki User

โˆ™ 2015-07-15 18:28:51
This answer is:
User Avatar
Study guides


20 cards

What type of circuit in which all parts are connected in a single loop

What angle is between 90 and 180

What condition has symptoms that include ringing buzzing or roaring in the ears or head

What is the transfer of energy as electromagnetic waves called

See all cards
24 Reviews

Add your answer:

Earn +20 pts
Q: How do you add a separate light switch?
Write your answer...
Still have questions?
magnify glass
Related questions

How do you add a light to a switch from a different circuit?

Add a light to switch from a different circuitI think here your concern is that you don't want change the performance of the circuit to which you add the you have to use a relay or a solid state relay to the circuit and a separate power supply to the light in compliance with all the safety rules.

Why does the parking light stay on when you turn the car off?

because the lights are not controlled by the ignition switch; they are controlled by a separate light switch.

Where is the button to shut of the back hatch light on a 1994 mercury villager?

There is no separate switch for it. Pushing the light switch will defeat the dome and courtesy lamps.

Can you take power from a switch to add a new light and switch in another room?

Only if the existing switch box has an unswitched hot and neutral in it.

How can you power a second switch to operate another light separately from the original light power source?

well, it's not a requirement, but traditionally a single light on a single switch has hot, neutral and ground brought directly to the light fixture from the panel. this circuit is called the home run. the hot is then run to the switch and back to the light as switched hot, which is used to feed the light. in order to add a second switched light fixture on a separate switch, you could pick up hot, neutral and ground at the first light fixture and carry it in another circuit to the second light fixture (traditionally) OR to the second light switch directly, whichever is easier. if you carried the hot/neutral/ground to the second light fixture, you would then circuit hot and switched hot to/from the second switch. if you carried hot/neutral/ground directly to the second switch, you would have to switch the hot and carry switched hot/neutral/ground to the second light. the same is true if the first switch has the home run, only you would add a circuit from the first switch to the second light fixture (or switch) instead of from the first light fixture.

How do you separate 2 lights from 1 switch?

It depends on where the feed to the two lights comes from. If the second light is fed parallel with the first light just isolate the second feeder from the first light. If the two lights are feed from the switch box, isolate the light from the switch that you do not want to operate.

Why does turn signals and brake light work but the hazards dont?

Separate circuits, separate fuses, separate flasher relay. Check the hazard fuse, hazard flasher and hazard switch.

How do you add a light to a single switch?

It all depends on where the live power is at (the switch or at the light). If power is at the switch, put the black wires on the switch and tie the whites together (assuming there are only 2 cable assemblies in the box). If power is at the light it becomes a little tricky, which I won't go into here.

Can you wire the vanity light to the exiting light from the ceiling?

Yes if you are sure it won't overload the circuit. You may want to install a separate switch as well.

How do you wire a two way switch one controls the outlet the other the outdoor light with a pigtail?

You need two separate switches. You can get two switches that are in the same form factor as a single switch (2 gang switch). You use one switch for the outlet and the other for the light. You switch the black wires which are "hot".

How do you add a light switch to a ceiling fan that doesnt have a pull switch. i installed a light kit but theres no way to turn off the light. do i drill a hole and add a switch to existing wiring?

Some brand fans have a remote control kit that installs in the fan housing. Also if you have access you can run a separate switched voltage to the fan. In this case you would have to put a second switch in the same box that controls fan, unless it is a switch with speed control that came with fan. In this case you would have to install a new box (Old Work Switch Box from Home Depot or Lowes for example) and run voltage to the box, install a switch and run wire to fan and connect to light. One other possibility is to check the ceiling box and see if there is a spare red wire. If so you could use this to switch power to the light separately from the fan. Again it depends on the switch configuration and supply voltage feed.

What is the function of the light switch on a microscope?

What is the function of the light switch on a microscope?

People also asked