Workplace electrical equipment: what is likely to lead to incidents or electrical fire

Anywhere electricity is used has the potential to cause a fire. These are some of the most common sources of electrical fires.

• Extension cords. They are often used to get electricity where it is needed, but they typically run across the floor or through other unprotected areas. They can be damaged, leaving an exposed wire that can ignite flammable material nearby.
• Overloading a circuit. Plugging too many things into one circuit can cause a fire. A circuit breaker should prevent this, but it is still a risk because the wires or other components can overheat.
• Faulty outlets. If an outlet is not properly installed or is damaged, it may cause a spark or another event that starts a fire.
• Light fittings. Fitting bulbs of too high a wattage for the fitting, or a fitting that is not properly ventilated, can cause a fire.
• Poor maintenance. Excess dirt, grease or other build-up on any part of a portable electric power tool, including ventilation openings.
• Overheating during charging. Equipment may overheat while it is being charged.
• Misuse. For example carrying a drill by its cord, walking over electric cables, or physical abuse such as pulling a plug out by tugging on the flex. Another example is pushing wires directly into a socket instead of using a plug.
• Heat and sparks in normal operation. Some workplace electrical equipment, such as a grinder or welding machine, produces heat or sparks as part of its normal use.

Use of defective or poorly maintained workplace electrical equipment

Some common causes of accidents with portable electrical equipment:

• Unsuitable equipment. For example using equipment that is not intrinsically safe in a flammable atmosphere.
• Inadequate maintenance. Excess dirt, grease or other build-up on any part of the portable power tool, including ventilation openings.
• Use of defective or poorly maintained equipment. This includes carrying on using faulty equipment, and a lack of routine inspection, testing or maintenance, or repairs carried out badly or by unauthorised people.
• Use in wet environments. Water lowers the resistance of objects and surroundings to the passage of electricity, so any work with electrical equipment in a wet environment raises the risk. Shocks are more likely, and the injury can be more severe, because lower resistance means higher current flow.
• Use in hazardous environments. A flammable atmosphere may be present which the electricity can ignite.
• Overheating of portable equipment during charging. This can come from defective batteries, incompatible chargers or too little ventilation during charging. Overheating may damage internal components, which can ignite the equipment itself or any combustible material nearby and cause a fire.

Summary notes for Element 11 · Cheat sheet · Glossary. A study aid, not published or endorsed by NEBOSH.