One of the most common misconceptions about electricity is that it’s dangerous. Actually, electricity can be quite safe if you know what you are doing and have the right tools for the job. That is why an electrician needs a variety of electrical testers to identify any problems with circuits or wiring before they turn into major safety hazards.
Some basics about testers before we get into the detail. Generally speaking, there are 2 types, multi-functional testers and single dedicated testers. Multi-functional testers are instruments that combine the functions of several testers, such as voltage tester, continuity tester, and current tester. Dedicated testers have a single function, such as insulation tester, ground detector or circuit breaker tester.
Furthermore, electricians will test 2 types of circuits, AC or DC. AC stands for alternating current, which is the type of electricity that standard outlets use in homes and offices to power computers, televisions, clocks, etc. The other type is DC, or direct current, which is the type of electricity that’s used by cars in many countries.
This is a non-contact voltage tester that uses induction. It is good for finding wires behind walls, floors and ceilings because it emits an electromagnetic field which gets picked up by the conductor. It is considered to be among the safest testers, since it does not require you to expose any live wires.
Simply use the tester an insert it into an outlet socket or by touching the outside sheathing of a wire to detect whether there is live current. Inductance testers are powered by a 9V battery and have a sound meter for maximum distance of detection. It is important that the battery is always fully charged as the tester will not work if the battery is low.
These testers are general single function type, and will only measure voltage, and not continuity, current or anything else. They are quite common for DIY homeowners.
2. A Neon Voltage Tester
This is a simple and popular device that can detect whether there is live current in a circuit without the need to open the breaker. However, unlike a non-contact voltage tester, a neon tester will require that you expose the live wire to determine if there is voltage.
The neon tester has a built-in neon bulb that lights up when it detects current. Also, it only indicates whether voltage is present or not, and will not indicate the voltage level.
It is not battery powered. It is connected directly to the circuit being tested by inserting one of its 2 leads into a standard outlet or receptacle and touching the other lead to the wire being tested.
It is important that you hold the tester on the plastic handles to avoid getting an electric shock.
3. A Plug-In Circuit Analyzer
These testers are used in homes and offices to check if circuits can be used safely. They will indicate a great deal by simply plugging it into an electric outlet. The plug-in circuit analyzer will only work if the power outlet has all 3 terminals connected to it, in other words, the outlet must be grounded.
The older 2 prong type outlets will work better tested with a neon voltage tester. The plug-in analyzer have 3 neon lights, and each will represent a different reading.
It is advisable that you use the reading chart provided with the product to determine if the circuit is grounded, has proper polarity, and can safely use appliances.
4. A Continuity Tester
Firstly, always make sure that you are using a continuity tester on a circuit that is turned off. As its name implies, this tester will let you know if there is continuity or connectivity between 2 points. That means, if the tester lights up, it will indicate that the circuit is connected and that there is no break in the circuit.
This tester will not work if you try to use it on an active circuit, as it will not be able to tell you whether the circuit is connected or grounded.
A continuity tester is very useful to test appliances that are completely disconnected from the power supply, such as lights and doorbells.
5. A Multimeter Tester
A multimeter tester is a more versatile device, as it can not only detect continuity and polarity, but it can also test the voltage of the circuit. It is the most multi-functional tester in the list of electrical testers used by electricians.
Most, if not all multi-testers can provide an accurate reading of voltage, current and resistance. It can also measure AC and DC, frequency and capacitance.
Some models, like the Fluke-117 for instance, can measure temperature. The fluke-117 can provide you with all of this information by simply flipping the selector toggle. Fitted with digital display, this tester is particularly useful when you need perform electrical testing in the dark.
In conclusion, this may not be a comprehensive list of the electrical testers used by electricians, but these are the more common ones. You can pair them up to make them even more versatile – at least this is a starting point.