Circuit Concerns: Basic residential electrical safety and overloading

Published On
Aug 15, 2022

According to the Electrical Safety Foundation International, there are about 51,000 home electrical fires each year. They account for nearly 500 deaths, over 1,400 injuries and more than $1 billion in property damage. Many of those fires occur as a result of overloaded circuits, which can be prevented.

Be careful of overloading

When too many appliances, electronics or other devices are plugged into an outlet or circuit, an overload can occur. It can also happen if one device draws too much power or the wrong-size wire was used to complete the circuit. If this happens, the electrical current can heat the wires to a very high temperature. An overload in an electrical system is dangerous because it can produce heat or arcing. Wires and other components in an electrical system or circuit can only safely carry a certain amount of electricity.

According to the Oregon Occupational Safety and Health Division, “Excessive heat can melt insulation and lead to arcing which can create ground faults or fires. In order to prevent too much current in a circuit, a circuit breaker or fuse is placed in the circuit. Breakers and fuses do the same thing: open the circuit to shut off the electrical current. If the breakers or fuses are too big for the wires they are supposed to protect, an overload in the circuit will not be detected and the current will not be shut off.”

Therefore, it is imperative to be familiar with the location of panels and circuit breakers in case of an emergency. All circuit breakers and fuse boxes should be easily accessible, clearly labeled and never blocked. This means that each switch should be positively identified as to which outlet, appliance or equipment it is linked to.

When replacing a fuse or breaker with one rated at a higher capacity, it’s important to use the correct wires or equipment. The table below demonstrates the current carrying capacity of different wire sizes.

Other protections

Additional protections against overloading circuits include adhering to the manufacturer’s amperage or wattage rating for cords, appliances, electronics, tools or any other equipment and inspecting each device for any damage or exposed wiring before use. When using a device that has wires or cords that become hot to the touch or produce smoke or sparks, remove it from the power source immediately.

Electrical outlets should also be inspected for loose-fitting plugs or other damaged components. If outlets are warm or hot to the touch or there are popping or sizzling sounds behind walls, unsafe wiring conditions may exist. Broken wall plates should be replaced prior to use. Avoid forcing a plug into an outlet if it doesn’t fit properly. Additionally, when using a tool or appliance with a three-prong plug, never remove the third prong for a two-conductor outlet.

If an appliance or tool repeatedly blows a fuse, trips a circuit breaker or has caused an electrical shock, unplug it immediately and stop using it. When fuses blow or trip frequently, the capacity of electrical service may need to be increased or new additional branch circuits might be needed.

Lighting concerns

Lamps and fixtures can also result in electrical overloads. It is important that the lamp wattage matches each fixture requirement. Lamps with higher wattage ratings than recommended on the fixture should be changed and screwed in securely to prevent overheating. Finally, shut off and replace light switches that are hot to the touch and lights that spark or flicker.

Electrical hazards become more dangerous if the worker, environment or equipment is wet. You don’t have to be standing in water to be electrocuted. Wet clothing, humidity and sweat can also increase the likelihood. As a result, GFCIs are required on construction and general industry sites where there is a wet environment or work that involves construction-like activities. GFCIs interrupt the current when there is a difference in current flowing in and out of the circuit. This action can prevent death or serious injury. GFCIs are different from circuit breakers because they detect leakage currents rather than overloads.

About the Author

Tom O'Connor

Safety Columnist

Tom O'Connor is safety and regulatory affairs manager for Intec, a safety consulting, training and publishing firm that offers on-site assistance and produces manuals, training videos and software for contractors. Reach him at toconnor@intecweb.com.

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