How to Test if an Electrical Wire is Live

A voltage tester is the safest way to test for a live electrical wire with there being many testers. The main ones are non-contact voltage testers and digital multimeters and are used to detect current flows. Voltage testers are not expensive and can be purchased from local hardware stores. Anyone can use them if they are handled correctly and know how to work with them.

This type of voltage tester is an extremely safe option to test for a live electrical wire. The tester is small in size while also being lightweight and created with durable plastic resin. Being safe to handle it does not require someone to make contact with the wire. The power is turned off when the device is used and inserted into an electrical outlet.

It works by lighting up and making a chirping sound when there is power present. Inspecting multiple wires and outlets can happen by simply moving the device close to the wires. However, the device is limited when it comes to inspecting wires that are covered with a metal sheath or conduit. Also, the tester can run our of charge or batteries quickly so constantly changing the battery is needed.

Digital multimeters are used to measure amps, voltage and resistance levels. By turning the knob on the device one can easily switch between the different readings. For testing if a wire is live through a digital multimeter the system should be set on AC voltage.

Using the device is done through putting the two probes which are on the device onto a red and black wire. Before the positive and negative wires are attached it is important that the power is switched off completely. The reading should be on the screen to determine if the wire is still live.

When using a digital multimeter is preferred over non-contact voltage testers is mainly for older buildings. Also, when ground wires are tested to see if they are actually connected to the grounding system. A non-contact voltage tester is often used first for testing outlets then wires are checked with a digital multimeter. They are both useful tools which provide accurate readings and insights if a wire is still live.

All commercial, residential and industrial buildings legally follow wiring rules by Wiring Rules AS/NZS 3000. These standards are placed which come with safety requirements for new technologies, installations and more. Including electrical wiring, rules such as wiring colours, all the wires in the building are consistent.

When working to test if electrical wires are live knowing the colour code of wires and the premise is important. Only working with the red or active wire is safe for untrained people in electrical work. The power should always be turned off to prevent any electrical dangers from occurring. Also, the Earth wire should be connected at all times as this protects people from electrical surges.

If curious to know more about what the earthing system is in an electrical system, read our blog article for more information.

How the colour codes of the wiring system are determined is from if the system is multiphase or single phase. Residential homes often have a single-phase system installed which is electrically connected at 230 – 240 volts. Commercial and industrial areas will use multiphase systems with the electricity connected at 400 – 415 volts. Here is how in Australia the wires are coloured in single systems:

• Active – Red
• Neutral – Black
• Earth – Green/Yellow

Here is multiphase systems and their colouring:

• Phase 1 – Red
• Phase 2 – White
• Earth – Green/Yellow
• Phase 3 – Dark Blue

Understanding what each coloured wire is is a useful skill that everyone should know. It will be extremely useful when needing to test if wires are live or not. Learning more in the electrical field, having a better understanding, is useful for daily living. For more information on basic electrical skills read our blog with four helpful tips.