Environmental, Health and Safety Services

Extension Cords

The following requirements apply to the use of cord-and-plug-connected equipment and flexible cord sets (extension cords):

  • Extension cords may only be used to provide temporary power.
  • Portable cord-and-plug connected equipment and extension cords must be visually inspected before use on any shift for external defects such as loose parts, deformed and missing pins, or damage to outer jacket or insulation, and for possible internal damage such as pinched or crushed outer jacket. Any defective cord or cord-and-plug-connected equipment must be removed from service and no person may use it until it is repaired and tested to ensure it is safe for use.
  • Extension cords must be of the three-wire type (except as specifically allowed by the NEC). Extension cords and flexible cords must be designed for hard or extra hard usage (for example, types S, ST, and SO). The rating or approval must be visible.
  • Job-made extension cords may comply with the following requirements.
  • Personnel performing work on renovation or construction sites using extension cords or where work is performed in damp or wet locations must be provided, and must use, a ground-fault circuit interrupter (GFCI).
  • Portable equipment must be handled in a manner that will not cause damage. Flexible electric cords connected to equipment may not be used for raising or lowering the equipment.
  • Extension cords must be protected from damage. Sharp corners and projections must be avoided. Flexible cords may not be run through windows or doors unless protected from damage, and then only on a temporary basis. Flexible cords may not be run above ceilings or inside or through walls, ceilings or floors, and may not to be fastened with staples or otherwise hung in such a fashion as to damage the outer jacket or insulation.
  • Cords must be covered by a cord protector or tape when they extend into a walkway or other path of travel to avoid creating a trip hazard.
  • Extension cords used with grounding-type equipment must contain an equipment-grounding conductor (i.e., the cord must accept a three-prong, or grounded, plug).
  • Attachment plugs and receptacles may not be connected or altered in any way that would interrupt the continuity of the equipment grounding conductor. Additionally, these devices may not be altered to allow the grounding pole to be inserted into current connector slots. Removing the grounding prong from an electrical plug is prohibited.
  • Flexible cords may only be plugged into grounded receptacles. The continuity of the ground in a two-prong outlet must be verified before use with a flexible cord, and it is recommended that the receptacle be replaced with a three-prong outlet as allowed by the NEC. Adapters that interrupt the continuity of the equipment grounding connection may not be used.
  • All portable electric equipment and flexible cords used in highly conductive work locations, such as those with water or other conductive liquids, or in places where employees are likely to contact water or conductive liquids, must be approved for those locations.
  • Employee's hands must not be wet when plugging and unplugging flexible cords and cord-and-plug connected equipment if energized equipment is involved.
  • If the connection could provide a conducting path to employees hands (for example, if a cord connector is wet from being immersed in water), the energized plug and receptacle connections must be handled only with insulating protective equipment.
  • Locking-type connectors must be properly locked into the connector.
  • Lamps for general illumination must be protected from breakage, and metal shell sockets must be grounded.
  • Temporary lights must not be suspended by their cords unless they have been designed for this purpose.
  • Portable lighting used in wet or conductive locations, such as tanks or boilers, must be operated at no more than 12 volts or must be protected by ground-fault circuit-interupters (GFCI's).

Power Strips

Power strips with circuit breaker (overcurrent) protection may be used in place of extension cords on a more permanent basis. Power strips are available with cords up to 15 feet long to provide greater flexibility in providing receptacles where needed. Power strips must be plugged directly into premise wiring (i.e. wall outlets or receptacles). Power strips may only be used in accordance with the manufacturer's recommendations, and one power strip may not be plugged into another power strip - known as "daisy chaining".