How to Find an Electrical Short
An electrical short happens when an accidental path is created in a circuit, generating a connection where there shouldn’t be one. It's usually very obvious when one happens as a short will reveal itself by fuses being repeatedly blown or the circuit breaker tripping repeatedly. It also usually causes a loud popping sound when the circuit is activated.
When a short occurs, it should be addressed right away since this problem could melt insulation on electrical wiring, damage the circuit itself, or even cause a fire. You can find and repair the cause of an electrical short yourself by following the steps below.
Step 1 – Check Appliances
The first thing to do is to check the electrical appliances you were using at the time of the short. Unplug the ones that are connected to the circuit, and then reset the breaker or change the fuse. Energize the circuit. If the breaker or fuse does not blow, then an appliance is most likely the cause. Next, test each to see which one is the culprit. It should then be repaired or replaced to remedy the issue. If the circuit trips out or blows the fuse again when the appliances are unplugged, then there is probably a short in the wiring or the receptacle.
Step 2 – Remove Wires
Turn off the circuit that is tripping or remove the fuse from the problem circuit. Then, take the volt/ohm meter and switch it to volts. Insert the metal probe ends into the problem receptacle and test for voltage to make sure the circuit is off. The voltage should be zero. Remove the receptacle from the box, and pull the wires out of the receptacle with the screwdriver and pliers.
Step 3 – Check Wires
Switch the volt/ohm meter to ohms this time. Check the wires for a short by placing each lead to one of the bare ends of the insulated wires; connect one lead of the meter to the black wire and the other to the white wire. If the meter shows infinite ohms, or O.L., then the receptacle is bad and has to be replaced. If the meter shows continuity, the short may be in the wire or the circuit breaker.
Step 4 – Remove Breaker Wires
Turn off the main breaker that controls the power and remove the cover from the box. Remove the wires from the problem breaker or fuse connection and the corresponding white wire. This white wire will be encased in the same insulated jacket as the black wire.
Step 5 – Check Breaker
Test the breaker and breaker wire for a short. If the volt/ohm meter shows infinite ohms or O.L, then the breaker needs replacement. If the breaker wire shows zero ohms or a resistance reading, then the wire is shorted and has to be changed.