A short circuit happens when there’s a power diversion due to unintended contact of components. This, in turn, results in lower resistance than that of a standard circuit. When this happens, the power source is likely to be damaged.
As such, it helps to know how to find a short circuit using a multimeter, which basically can measure several parameters, including voltage, resistance, and continuity.
In short circuit tests, the critical parameter to check is continuity, which transfers a charge from one end of a wire to the other end. If there is no continuity, then the wire has a “short.” The test helps you to find the location of the “short” without dismantling the whole system.
In this post, we’re going to share some exciting tips on how to find a short circuit with a multimeter. We hope that by the end of the post, you’ll carry out the task without any difficulty.
What Is a Multimeter?
A multimeter, also known as a multitester or volt-ohm milliammeter (VOM), is a measuring instrument that combines several different electronic measurement functions into one unit. The average multimeter will be able to measure current, voltage, and resistance.
Essentially, a multimeter combines the functions of an AC voltmeter, a DC voltmeter, an ohmmeter, and an ammeter into one. It measures multiple values. Hence, the name multimeter.
The multimeter was invented in the 1920s. Its invention is generally attributed to Donald Macadie, an engineer who worked for the British Post Office.
He was frustrated with the necessity to carry so many different instruments when he was maintaining telecommunications circuits. Because the instrument he invented was able to measure amperes, volts, and ohms, it was named the Avometer.
Nowadays, there are two common types of multimeters: analog multimeters and digital multimeters.
An analog multimeter functions by utilizing a microammeter, a micro version of an ammeter (derived from “ampere meter”), which measures current in a circuit, which displays readings by using a moving needle.
A digital multimeter (DVOM, DMM) possesses a numerical display to show readings and may also have a graphical bar to represent the measured values.
Causes of short circuits
Various reasons for a short circuit commonly known are:
- Wire insulation with a broken circuit; Damaged or old insulation wires can allow hot or neutral wires to contact each other. In return, this may cause a short circuit.
- Loose wire connection
- A wiring appliance that is damaged
Once you have suspected that you have a short circuit problem, you can follow an essential procedure to identify the problem’s location.
- Locate the circuit breaker that has gone off
- Inspect all power cords that connect to the circuit breaker that has tripped
- Turn off all appliance switches and lights that are alongside the tripped circuit breaker, then switch it back on
- Switch on each appliance socket or light one after the other until you get to the circuit that has a short.
- Check the problem of the circuit or the wiring using a multimeter.
Here, you can either use a digital or an analog multimeter to measure resistance, voltage, and current.
How To Find a Short Circuit with a Multimeter
Step 1. Check your equipment
The first thing you’ll need to do to find a short circuit is to look for physical signs. This may include visible burns or metal on wires, burning smells, or flickering lights. Once you’ve identified a potential short, use your multimeter to confirm the voltage by setting it to resistance or continuity setting.
If you notice a lower-than-expected resistance, then that’s a clear indication that the current is being diverted away from the area, and there’s a short circuit.
Step 2. Test and Repair
After you’ve confirmed the short circuit source, make sure that you shut off the power to the electrical circuit by turning off the circuit breaker. You should then switch the multimeter from the resistance setting to AC volts and insert the metal probes into the problem receptacle or switch.
Your multimeter should show zero volts. That indicates that there’s no power running through the electrical circuit. If there is voltage present for some reason, you’ll have to find the right circuit breaker and repeat the procedure to verify that there isn’t any current in the electrical circuit.
Step 3. Check terminal boxes
Now that there’s no power in the electrical circuit, you can switch the multimeter to ohms and check the wires. If your multimeter shows infinite ohms or OL, that means that the breaker could have deteriorated and tripped from a lower current flow. In this case, you need to access the main panel and replace it.
If the multimeter shows continuity, there is a short circuit. It could be caused by a faulty breaker, broken wire, or a defective receptacle or switch. To resolve the short circuit, replace the defective receptacle or switch.
If you still get a continuity reading on your multimeter, be sure to inspect all the wires to ensure none of them show bare copper that could touch somewhere and short out. If everything is okay, screw the cables back to their original terminal and reinstall them in the box with the wall plate.
Well, at this point, we hope you’re familiar with how to find a short circuit with a multimeter. This guide is ideal for beginners who want to understand how to carry out basic electrical tasks.
Today, we increasingly depend on electricity to run a lot of things in our home. But with most things, you’re likely to encounter problems with your electricals. For some people, the first step is to call an electrician, which is undoubtedly a wise thing to do.
But for others, such problems offer an opportunity to put their electricity knowledge to use. Thanks to the growing availability of multimeters, you can easily find one to use at home or work. A multimeter allows you to find short circuits and address the problem before it even worsens.
Take the time to find the right multimeter that suits your needs. The market offers a wide range of options, from basic devices to high-end options. If you plan to use the meter for advanced tasks, then a high-end meter can be a great option. Such options come with great features, including Bluetooth connectiv