How to Find a Short Circuit with a Multimeter (6-Step Guide)

Have you encountered the problem of short circuits when working with electrical circuits or devices? When a short circuit permanently damages your electrical circuit or circuit board, it becomes even more of a problem. Detecting and repairing a short circuit is critical.

While there are different ways to detect a short circuit, using a multimeter is one of the easiest. As a result, we have made this comprehensive explanation of how to find a short circuit with a multimeter.

What is a short circuit?

A short circuit is a sign of a broken or frayed wire, leading to a malfunction in the electrical system. It is formed when a current-carrying wire comes into contact with neutral or ground in a circuit.

Also, it could be a sign of a short circuit if you see the fuses blowing regularly or the circuit breaker tripping frequently. When the chain is triggered, you may also hear loud popping sounds.

A multimeter is one of the basic tools you can use to check for shorts in your home's wiring. With it, you can check for electrical problems such as a short to ground. A multimeter can even test for a short on a circuit board, such as on a desktop computer. In addition, it can also check for short circuits in your car's electrical wiring.

Steps to find a short circuit with a digital multimeter

By repairing the short circuit as soon as possible, you will reduce the risk of damage to the wire and insulation and prevent the circuit breaker from burning out. (1)

To find a short circuit with a multimeter, follow these steps:

Step #1: Stay Safe and Prepare

It is extremely important to make sure that everything is done safely before using a multimeter to determine the short circuit. This ensures that neither your electrical circuit nor your multimeter is damaged while searching for a short circuit.

Before investigating anything, make sure your electrical circuit is off. This includes removing batteries and power adapters.

Note: If you do not turn off all power to the circuit before testing it, you may receive severe electric shock or electric shock. Hence, double check that the electricity in the circuit is off.

Step #2 Turn on your multimeter and set it up. 

Turn on the multimeter after double checking everything is safe to use. Then use the switch knob to set it to either continuity test mode or resistance mode, depending on the capabilities of your multimeter.

Tip: If your multimeter has other resistance settings, it is recommended to select the lowest resistance scale.

Step #3: Check and Adjust the Multimeter

To ensure that your multimeter will provide you with all the measurements you need, you must test and calibrate it before use. To do this, connect the probe tips of your multimeter.

If it is in resistance mode, the resistance reading on your multimeter should be 0 or close to zero. If the multimeter reading is much higher than zero, calibrate it so that when the two probes touch, the value will be zero. On the other hand, if it is in continuous mode, the light will flash or the buzzer will sound and the reading will be 0 or close to zero.

Step #4: Locate the Schematic Component

After setting up and calibrating the multimeter, you need to locate and identify the circuit components that you will be testing for short circuits.

The electrical resistance of this component, most likely, should not be equal to zero. For example, the input of an audio amplifier in your living room next to your TV will almost certainly have an impedance of several hundred ohms (at the very least).

Bonus: Make sure each component has at least some resistance when choosing these components, otherwise it will be difficult to detect a short circuit.

Step #5: Explore the Circuit

After locating this component that you will test for a short circuit, connect the red and black probes of your multimeter to the circuit.

The metal tip of the black probe should be connected to ground or the electrical circuit chassis.

Then connect the metal tip of the red probe to the component you are testing or to the area you think is shorted. Make sure both probes are in contact with a metal component such as a wire, component lead, or PCB foil.

Step #6: Examine the multimeter display

Finally, pay attention to the reading on the multimeter's display as you press the red and black probes against the metal parts of the circuit.

• Resistance Mode - If the resistance is low and the reading is zero or close to zero, test current flows through it and the circuit is continuous. However, if there is a short circuit, the multimeter display will show 1 or OL (open circuit), indicating a lack of continuity and a short circuit in the device or circuit being measured.
• Continuity Mode - The multimeter displays zero or near zero and beeps to indicate continuity. However, there is no continuity if the multimeter reads 1 or OL (open loop) and does not beep. Lack of continuity indicates a short circuit in the device under test.

Tips for Using a DMM to Find a Short Circuit

A multimeter can be used to check short circuits and characteristics of your circuit as it can function as a voltmeter, ohmmeter and ammeter.

Choose the right device                             

To check for short circuits in an electrical circuit, make sure you are using an appropriate type of multimeter. While all multimeters can measure current, voltage, and resistance, higher-end multimeters can perform various other tasks. For a more versatile multimeter, it may have additional readings, attachments, and modes.

Check out the features and details                        

The large display, selection knob, ports and probes are the main components of your multimeter. However, earlier analog multimeters included a dial and needle instead of a digital display. There can be up to four ports, half of them are red and the other half are black. The black port is for COM port and the other three are for reading and measuring.

Recognize your device's ports

While the black port is used for COM connection, the other red ports perform different functions. The following ports are included:

• VΩ is a unit of measure for resistance, voltage, and continuity testing.
• µAmA is a unit of measure for the current in a circuit.
• 10A - used to measure currents from 200 mA and above.

Listed below are other tutorials and product guides that you can check out;

• How to test a circuit breaker with a multimeter
• How to determine the neutral wire with a multimeter
• best multimeter

Recommendations

(1) insulation - https://www.energy.gov/energysaver/types-insulation

(2) making fire - https://www.rei.com/learn/expert-advice/campfire-basics.html