How To Identify Switch Live Wire? Step By Step (Easy Thing!)

How To Identify Switch Live Wire? |

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Changing a light fitting is an easy job to do. However, when you try to install the new light fitting, it seems confusing. There are many wires, and you may not know which one is the switch live wire. So how to know which wire is it?

How To Identify Switch Live Wire?

Before identifying which wire the switch live wire, you have to follow safety steps, then start working. These steps are:

1- Safety First

The first thing you need to do before starting is isolating the circuit. You can turn off only the switch for the circuit you are working on. For example, if you are changing the light fitting for the lights upstairs in your house. They can have a switch that controls them only; you can turn it off.

However, it’s recommended for your safety to turn all the switches in the house before starting to work. And you have to tell everybody you are working, so no one turns them back on. Before turning off all the switches, turn off any plugged device, like a washing machine or a computer.

2- Get Your Tools

You need to get a test meter to determine the switch live wire. Adjust the test meter to Ohms to measure the resistance. Then, put it on the bleep test to bleep when you get the right values. Touch the test meter’s red arm using the black arm to ensure there is no resistance.

3- Sort The Wires

Start sorting the wire try to determine which wire belongs to which cable. Each cable consists of two wires. Usually, each wire will have a different color. The wires can be either blue and brown or green and yellow. Sorting the wires is very important because when you use the test meter, you have to test the wires of each cable.

4- Use The Test Meter

First, choose a cable to work on; put the red clip on one of the cable’s wires and the black clip on the cable’s other wire. Then, turn on and off the switch and listen if the test meter bleeps. If the test meter doesn’t bleep, move to the next cable.

You have to know that if you put a clip on a wire from a cable and the other clip on a wire from another cable, that would give you no result. So you have to be sure you are using the two wires of the same cable unless you can’t find your switch live wire.

5- Moving To The Next Cable

You have to move to the next cable start installing the test meter clips on its wires. Then, turn on and off the switch; if the test meter doesn’t bleep, move to the next one. But if the test meter beeps, then these are the wires leading to the switch live wire.

You could mark these wires for the future if you need to change the light fitting again. So you don’t need to search for them again using the test meter. For example, you can use insulation tape on them of distinctive colors to mark them.

6- Setting Back Your Circuit

Now you know which is the switch live wire, you can set back your circuit. First, connect the neutral wires to the neutral block, then connect the live wires to the live block. When the switch is turned on, the current passes from the live wire back up to the neutral wire and energizes it.

Here’s a detailed video on how to identify switch live wire:

How To Identify Switch Other Wires?

Any switch is connected to a bunch of wires. Each wire has a function, and it can be used in particular tasks, so it’s important to know the difference between them.

1- The Ground Wire

The ground wire is the green or bare copper one; you may not find the ground wire installed on your switch. Because you may have an old switch, the wire can be clustered in the back of the wall. The ground wire is essential for your safety, it allows any surge of power to pass through it, and the wire disperses it somewhere safe.

2- The Line Wire

The line wire is the wire used for voltage supply. It’s used to supply the switch with 120 volts from the electricity source. It has black color in most cases.

3- The Load Wire

The load wire connects the socket to the load; it’s the connection between the lamp and the switch. It can have the same color as the line wire black, or it can be red-colored. But in case both have the same color, you can differentiate between them using each wire position.

4- The Neutral Wire

The neutral wire is responsible for carrying the current back to its source; usually, it’s white-colored. But if you have an old switch, you may not find the neutral wire connected. However, you can find it clustered in the back of the wall box.

Does it Mater Which Wire Connected to The Switch?

The old light fixtures use a metal ring to which the light bulb is connected. This metal ring is connected to the neutral wire, which can have two different colors based on the country, for example. In America, it’s white-colored, while internationally, it’s blue-colored.

The hot wire is the one used to conduct the switch. It’s bare and exposed to the metal tab of the bulb socket. So the user is protected from touching it, which can shock the person. The hot wire can have different colors brown, red or black.

The ground wire is used for safety; it allows any power surge to pass throw it and disperse it safely. For example, the metals in a light fixture can get energized from a failure or other leads. The ground wire can be either bare or green-colored.

Thus, in the old fixtures, the switch’s wiring will matter. However, if the fixtures or the switches are not that old, it’s double insulated. Then. It doesn’t matter which wire is connected because the electricity can change its direction about 100 times per second.

How to Identify Live and Neutral Wires?

It’s important to know which wire is which when you are working on electricity tasks, you can know each wire type following these steps:

1- Get Your Tools

To know which wire is which you will need a multimeter. After you get the multimeter, adjust it to the volts, it’s marked as on the multimeter with a line drawn above it. Then, you should be able to see AC on the left of the multimeter’s display.

2- Use The Multimeter

Before using the multimeter, you need to ensure that the wires you are testing are connected to an outlet. The wires should always not touch each other for your safety and the safety of the used device. Then, start putting the multimeter’s red probe on one of the wires you want to test.

Use the multimeter’s black probe to touch a ground object or the ground wire. If the multimeter gives voltage or beeps, this is the live wire. But if the multimeter doesn’t beep or the voltage is less than one volt, this is the neutral wire.

How To Wire A Light Switch?


Light switches are single-pole switches; this is the simplest type of switch. Inside the switch is a track carrying electricity, one ground, and two terminals. You can flip the toggle to make or break the circuit and control the flow of electricity.

The Wiring Steps

  1. Turn off the power by disconnecting the source of power.
  2. Connect the black live wire to the switch bottom terminal.
  3. Connect another hot wire to the light fitting.
  4. Get a white neutral wire, and connect it to the wire nut inside the switch box.
  5. Then, connect another white neutral wire to the light fitting from the wire nut.
  6. Get a ground wire and connect it to the wire nut inside the switch box for safety purposes.
  7. Then, connect a ground wire to the wire nut from the switch ground terminal.
  8. Connect another ground wire to the ground wire nut from the ceiling box.

The switch now is off. But, when you turn on the circuit, electricity reaches the switch, but it doesn’t flow across because the switch is incomplete. But, when you turn the switch on, the circuit is closed, and electricity now passes through the light to turn it on. And then it can get back to the breaker’s panel.

How To Wire 2 Way Light Switch?

A 2 way light switch can be used in many different ways. For example, you place a light switch at the top and bottom of a set of stairs or different doors in a room. The name for these types of switches depends on the country. The US/North America call these three-way switches. But the EU calls these two-way switches.

You can move the switch in two ways, up or down. But if you take a look at the switch’s back, you will see there are three terminals, which means the electricity can move through four different ways. These will all depend on the switch wiring. The first terminal is called the common, and then two terminals are called line one and line two.

The Wiring Steps

  1. Cut the live wire feeding the lamp, and connect the terminal “L1” to the live wire.
  2. Connect the switch two terminal “L2” to the switch one terminal “L1” using a grey wire.
  3. Put a brown mark on the wire to warn that it’s a live wire.
  4. Then connect the two terminals of each switch using a brown wire.
  5. Connect the switch two terminal “L1” to the switch one terminal “L2” using a black wire.
  6. For safety purposes, Put a brown mark at each end of the wires to warn that it’s a live wire.
  7. Connect the light fitting to its supply terminal “L2”.
  8. Use a brown mark on the wire to warn that it’s a live wire.

The electricity can now flow, and it will pass through switch one and into switch two, where the circuit is open. If you turn switch two, you close the circuit so the electricity can pass from the common and out into the lamp. If you turn the switch one, you open the circuit to the light fitting, then the lamp is off.

Related Readings:

How to Identify Wires in a 3-Way Switch?

Do You Need Isolators For Kitchen Appliances?

How To Test If Wire Is Live/Hot Without a Multimeter?

How To Identify a Traveler Wire in a Three-Way Switch?


Remember the electricity can be dangerous and fatal. So when you are dealing with electricity, you have to be very cautious. To identify switch live wire, you have to look for safety first, then prepare your needed tools. If you know your switch wiring, you can install any fixture you want without any confusion.

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