06 Jul Electrical Equipment Guarding
Electrical Equipment Guarding and Workspaces
Electrical current is found in power lines, transformers, breaker boxes, and power outlets and switches. Exposure to electric current can cause shock, injury and electrocution. Workers that service electrical sources need to get training on electrical safety, assume electrical equipment and lines are live, and use lock-out/tag-out procedures. Proper guarding and clearance around electrical equipment can prevent accidental worker exposure to electrical currents.
A shock can occur when a worker’s body becomes part of the flow of an electrical circuit. The severity of injury depends on the voltage and time that the electrical current passes through the body. Low voltage causes pain and slight burns, a large voltage can cause severe burns and stop the heart. A minor shock may cause a large injury if a surprised worker takes a fall.
To avoid the risk of accidental shock, live electrical components operating at 50 volts or more must be guarded with covers or other permanent barriers to prevent accidental contact by workers and their tools. Equipment can also be locked behind an enclosure, in a room, or at an elevated height. These areas should have restricted access and warnings against unauthorized entry. Permanent markings on electrical equipment with the voltage, current or wattage provide power output information for workers.
Electrical boxes and equipment are best stored in areas free from moisture, chemicals, and excessive temperatures. Electric cabinets with ventilation holes need to remain clear to allow air circulation. Electric parts that ordinarily spark or arc require covers and isolation from combustion sources. Equipment should be securely mounted to the surface that it rests on.
There should be adequate working space to allow workers to safely maneuver around electrical equipment. Electrical equipment with a voltage of 0-150 requires 36 inches of clearance. A voltage of 150-600, where there are energized parts on one side, also needs 36 inches of clearance. Equipment with a voltage of 150-600 and exposed energized and grounded parts on either side requires 42 inches clearance; equipment with exposed energized parts on both sides must have 48 inches clearance.
The clearance workspace around electrical equipment is not intended for storage. The area should be kept clear to allow safe movement and to prevent a fire hazard. Electric equipment workspaces require adequate lighting for safe work; light operating switches should not be near live electrical feeds. Enclosures need at least one entrance and enough headroom to work safely.
With adequate clearance and guarding around electrical equipment, workers can avoid accidental exposure to electric shock.