How to determine which wire is hot without a multimeter (4 methods)

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Method 1: use a proximity detector
Method 2: Use a tester screwdriver
Method 3: use a light bulb as a tester
- How to make a light bulb detector
- Using a light bulb to identify a live wire
Method 4: Using Color Codes

In this article, I will show you how to identify a hot or live wire without using a multimeter.

A multimeter allows you to check the polarity of the wires; however, if you don't have it, there are other ways to do the same. As a trusted electrician, I've learned a few tips and tricks over the years to pinpoint a live cable without using a multimeter, which I can teach you. Alternatives may help you because a multimeter may be too expensive for your one-time task.

In general, if you don't have a multimeter, you can use:

Voltage detector
Touch the screwdriver
Connect light bulb to wire
Use a standard color code

I will cover each in more detail below.

Method 1: use a proximity detector

I understand that this step may also not be available if you don't have access to any of the electrician's tools, in which case I would suggest that you move on to the next three.

Follow these simple steps to determine if a wire is hot using a non-contact voltage detector.

Step 1. Keep the proximity detector close to the object or test.

Step 2. The indicator on the detector will light up.

Step 3. The non-contact voltage detector will beep if there is voltage in an object or wire.

Step 4. You are checking that the current flowing through the wire is critical.

Tips: Do not hold the voltage detector by the probes, wires or any other part of the tester during the test. This may damage the tester and make it unsafe to use.

Most detectors work by inducing an alternating magnetic field in the object being tested. If the object is energized, the induced magnetic field will cause an electric current to flow. The detector circuit will then detect the current and beep.

However, make sure the non-contact voltage detector is working before use. This is very important because misleading results can lead to huge damage and accidents.

Method 2: Use a tester screwdriver

Another way to determine if a wire is hot or live is to use a tester screwdriver.

ORDER

Step 1: expose the wires

You can open the cover or remove anything that makes the wires inaccessible.

Maybe you want to check the wires behind the switch; in this case, unscrew the cover of the switch to access the wires you want to check the polarity.

Step 2: Find the exposed point on the wire

Because most wires are insulated, you need a perfect and bare spot to touch the tester's screwdriver.

If you can't find a bare spot on the wire where you could put the tester's screwdriver, I recommend stripping the wire. But first, you must turn off the power to the device you are working with on the switch panel. Do not strip live wires without proper experience. You may be electrocuted.

Do the following:

Get a wire stripper or insulated pliers.
Pull out the wires you want to check the polarity
Insert about half an inch of wire into the jaws of a wire stripper or pliers and cut off the insulation.
Now you can restore power and continue the test.

Step 3: Touch the tester's screwdriver to the bare wires.

Before proceeding with the actual testing, make sure your tester's screwdriver is sufficiently insulated to avoid accidents.

After that, grasp the insulated part and touch the exposed or stripped wires. Make sure the tester's screwdriver makes good contact with the wires.

In parallel, check the neon bulb on the screwdriver, if you touch the hot wire (with a screwdriver tester), the neon bulb will light up. If the wire is not energized (ground or neutral), the neon lamp will not light up. (1)

Attention: A defective tester screwdriver may give incorrect results. So, make sure your screwdriver is working. Otherwise, you may have a short circuit.

Method 3: use a light bulb as a tester

First, you need to make this detector easy to use. You can then use it to test the hot wire.

How to make a light bulb detector

Step 1. Please note that the light bulb must be connected to one end of the wire. So, the light bulb must have a neck connected to the wire.

Step 2. Connect the other end of the wire to the plug to be inserted into the socket.

Attention: not a problem if you connect black, red or any other wire to the bulb; the light of the tester should touch the hot wire and light up - this is how you identify the hot wire.

Using a light bulb to identify a live wire

Step 1. Determine the ground - green or yellow.

Step 2. Take the tester and connect one end to the first cable and the other to the ground wire. If the light comes on, it is a hot wire (the first cable). If not, it could be the neutral wire.

Step 3. Check the other wire and observe the behavior of the light bulb.

Step 4. Note the live wire - the one that lit the bulb. This is your live wire.

Method 4: Using Color Codes

This is perhaps the easiest way to pinpoint a live or hot cable in an electrical appliance or wiring harness; however, not all electrical appliances have the same wire codes. In addition, wire codes vary by country and region. The following is a residential color standard for electrical wires.

In most household lighting fixtures, the wire code is as follows (US National Electrical Code)

black wires - are wires energized or energized.
Green or bare wires – designate grounding wires and connections.
yellow wires – also represent ground connections
white wires – are neutral cables.

This color standard is established by the National Electrical Code and maintained by the National Fire Protection Association. (2)

However, due to differences in color standards in other regions, you cannot rely entirely on color codes to identify a live wire. Also, do not touch the wires until you know which ones. In this way, you will minimize the chance of accidents.

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