The amount of current needed to light an ordinary 60-watt lightbulb is five times what can kill a person. Therefore, all electrical equipment on a construction site is potentially deadly.

Because of the sheer number of electric extension cords and the rough conditions in which they are used on a construction site they can become both damaged and easily ignored for hazards. The continuous activity, along with the changing environment and high potential for damage can let these items quickly become a serious safety problem.

In addition to extension cords, crucial is the safe use and maintenance of every other piece of power equipment on a job site: nail guns, saws, drills, compressors, etc.

Make sure to inspect extension cords daily to confirm:

• All extension cords are three-wire cords.
• The ground pin is on a male plug.
• There is no broken insulation on the cord.
• End appliances (plug and receptacle) are gripped to insulation.
• All wires are continuous and unbroken.
• All cords are protected from damage, which is likely to occur when passing through a door or window.
• Metal boxes with knockouts are not used on extension cords.
• Plugs are dead-front (molded or screwed in place).
• Romex (nonmetallic sheathed cable) is not used as flexible cord.
• Cords are not stapled to place or hung from nails.
• Bushing is passing through holes in covers or outlet boxes.

Other electrical items to check:

• Temporary lights are not supported by / hanging from cords.
• Bulb guards are used on temporary lights.
• Electrical power tools with non-dead-man switches have a magnetic restart (to prevent injury to the operator that might result if motors were to automatically restart following power failures).
• Provisions are made to prevent machines from automatically restarting upon restoration of power in place.
• Outlets do not have reversed polarity.
• Power tools are double-insulated or have a ground pin.
• General maintenance and condition of power tools and equipment.
• Provide guarding of all exposed sources of electricity of more than 50 volts so no one can come in contact (receptacles, lightbulb sockets, bare wires, load center, switches).

Guarding tips for electrical components:

• Use approved enclosures and store them in a room, vault or similar enclosure accessible only to qualified persons.
• Arrange suitable permanent, substantial partitions or screens so only qualified persons have access to the space within reach of live parts.
• Store cords and power tools / equipment on a suitable balcony or platform that is elevated and arranged to exclude unqualified persons.
• Elevate electrical components eight feet or more above the working surface.