Causes and Effects of Short Circuits

Caused by internal faults, short circuits are abnormal currents that flow into equipment. The currents that flow in a short circuit are considered destructive energy. This energy needs to be held in the equipment or there can be dire consequences. Property damage, overheating machines, fire, and even explosions can occur when short circuits aren’t contained properly. Learn more about the causes and effects of short circuits to better protect your facility from the potentially devastating effects.

The per-unit calculator converts a radial one-line to a common base and estimates the three-phase bolted fault current at each bus.

Causes#

There are a few events that can cause a short circuit to occur. Even with the proper protection in place, sometimes a short circuit can exceed the interrupting rating of the safety fuses and circuit breakers, and damage can result. Here are some common causes of short circuits.

Lack of safety measures

If fuses and circuit breakers are not rated for the fault current a facility’s electrical system can deliver, they may fail to safely interrupt a short circuit when one occurs. Safety measures should regularly be checked to evaluate their ability to interrupt the currents that come from short circuits. For a first estimate of the fault current at one panel, try our available fault current calculator.

Using equipment outside its range

Using equipment within a facility outside its normal or expected function can cause short circuits to occur. Equipment should only be used within its own limitations.

Changes from the utility provider

Sometimes a short circuit can occur even when no changes are made within a facility. If a utility provider makes changes, it can affect the equipment used in the facility and even raise the risk of short circuits occurring.

Growing facility without changes in safety

As a facility expands, equipment and usage typically change. If the safety measures to protect against short circuits are not updated as the facility and usage grow, short circuit currents can exceed what the now-inadequate protective devices can safely interrupt.

Effects#

Some of the effects of short circuits are overheating, fire, and explosions. These all can lead to significant damage and even injury. One of the most dangerous outcomes from a short circuit is an arc flash. If a short circuit leads to an arc flash explosion, then extreme fire may be the result, which puts people in danger, both in the facility and the surrounding area, and threatens the building and the property within.

Preventing short circuits should be a top priority for facilities. Facilities can get a free arc flash quote to evaluate need for an arc flash assessment, which includes a walk-down of the site, software analysis, electrical coordination analysis, short circuit analysis, arc flash analysis report, and arc flash labels.