A standard 2-wire lighting circuit is shown in Figure 1. The brown wire is Live (also know as permanent live), this brings the live supply to the switch. The blue wire is known as the Switched Live and takes power to the light. Switched Live is only live when the switch is on (this is where it gets its name from).

How do you identify switched live?

With a live circuit, you can identify the ‘switched’ live conductor at the light fitting. Switching on the switch will make one of your blacks become live. With a digital multi-meter set this to AC volts. When the switch is closed you will see 230 V between neutral and the switched live black.

How do I check which wire is live?





Quote from the video:
Quote from Youtube video: And finally touch the red probe to each exposed wire. If you don't get a voltage reading the wire is neutral. If you get a reading the wire is hot you can also use color coding to identify.

How do you know which wire is which on a light switch?

Quote from the video:
Quote from Youtube video: And take a tester and see which one of the black wires is a live wire. So this is our live wire this is going to be our common terminal. Now if you try both of these black wires.

How do you tell which wire is live and which is neutral?

In most modern fixtures the neutral wire will be white and the hot wire is red or black. In some types of fixtures, both wires will be the same color. In this case, the neutral wire is always identified by some means. In some cases, there will be small writing on the wiring case.

How do I test a live wire UK?

To test for a live electrical wire either a non-contact voltage tester or a digital multimeter is used. A non-contact voltage tester is the safest way for testing live wires, performed by placing the machine near the wire.

How do I test a live wire with a multimeter?





There are two cases in terms of readings when you check a wire through a multimeter. Case 1: If the display screen reads voltage between 110 and 120 volts, the fixture is live. Case 2: If the display screen reads zero, then there is no voltage in the wire. In other words, there is no current flowing through the wire.

How do you test if a wire is live without a tester?

Using a digital multimeter is the easiest way to tell if a wire is live without a tester. It is also the safest way to test a live wire, especially if it is exposed. Set up the multimeter by rotating the dials to the V spot on the device.

How can you tell which wire is positive?

If you have a wire where both sides are the same color, which is typically copper, the strand that has a grooved texture is the negative wire. Run your fingers along the wire to determine which side has the ribbing. Feel the other wire which is smooth. This is your positive wire.

How do you test if a wire is live with a screwdriver?

Touch the tip of the tester screwdriver to the wire you’re testing, being sure to hold the tester screwdriver’s insulated handle. Look at the handle of the screwdriver. If the small neon light in the handle lights up, there is power going to the circuit. Otherwise the circuit is dead.

How do you tell which wire is hot if both are black?



As a further test, place the prongs of the multimeter’s wires on the bare metal on the ends of the two black wires. You will get a reading if one wire is hot and the other isn’t. However, if both wires are hot, the reading will be zero.

How do I test a power wire without a multimeter?

For testing the live wire without having the meter device, you can build your own tester. For example, get a socket and light bulb and attach a couple of wires to it, then touch one to the ground or neutral and another one wire to the test.

How can you tell if a wire is live or neutral UK?

Key Takeaways

  1. The new electrical wiring colours in the UK are green and yellow for the earth wire; brown for the live wire, and blue for the neutral wire.
  2. The old electrical wiring colours in the UK are green and yellow (or bare) for the earth wire; red for the live wire, and black for the neutral wire.

What Colour is switched live UK?



blue wire

The brown wire is Live (also know as permanent live), this brings the live supply to the switch. The blue wire is known as the Switched Live and takes power to the light.

What Colour wires are live?

Plug wiring colours

Wire Colour
Live Brown
Neutral Blue
Earth Yellow and Green


How do you test neutral wire?



This process is pretty straightforward; all you have to do is find a power outlet and set your multimeter to the highest point on the AC range. And with the aid of your black and red probe, touch each of the wires at the back of your outlet to determine if it’s hot, neutral, or ground.

Does neutral wire have voltage?

The neutral wire is often said to have zero voltage on it. If you touch that wire on a live system, however, you will often find out very quickly that technically having zero voltage is very different from meaning there is no electricity present.

What happens if the live wire touches the neutral wire?

Answer: The live wire touches the neutral wire. – This will create a short circuit as a large current which exceeds the fuse rating will from the live (240 V) to the neutral wire (0V) as that path has very low resistance. The fuse will blow.