Appendix E: Portable Workbenches

This section covers laboratory and shop workbenches that can be moved by sliding, rolling, etc. It does not cover built-in workbench assemblies that are permanently attached to structure surfaces. Such built-in assemblies must use appropriate fixed-wiring methods to provide power for receptacles, lighting fixtures, ventilation fans, etc., in accordance with the NEC.

Flexible cord and plug assemblies may be used to provide ac power to portable workbenches only when:

• The branch circuit voltage supplying the workbench is 150V or less.
• The overcurrent protection device rating on the branch circuit supplying the workbench is 20A or less.
• The flexible cord is no longer than 4.5 m (15 ft), is attached to the workbench with an approved tapered rubber-bushing cord-grip fitting, is no smaller than #14 AWG, is type-listed under the NEC as “Extra Hard Usage” (Type SO, G, W, etc.), is protected from physical damage, is routed to prevent tripping hazards, and is terminated in a listed attachment plug and mating receptacle interface that has the proper voltage and current rating for the branch circuit feeding the workbench.
• Each workbench has its own cord, attachment plug, and branch circuit receptacle. Workbenches must not be parallel fed or daisy chained by plugging their power cords into a receptacle located on another workbench.
• Each workbench wiring system has equipment-grounding protection that consists of a correctly sized and identified equipment-grounding conductor. This grounding conductor must be an integral part of the flexible cord. Grounding circuit continuity must be provided by the branch circuit wiring feeding the workbench, and at the interface between attachment plug and receptacle.
• All metal surfaces of the workbench assembly that are likely to become energized by an electrical fault are properly bonded to the equipment grounding conductor in accordance with the NEC.
• The number of workbench receptacle outlets is limited to no more than 10 duplex receptacles or 3 linear meters (10 linear ft) of wire-mold plug strip on a 15A branch circuit, or 13 duplex receptacles or 4 linear meters (13 linear ft) of an approved multi-outlet assembly on a 20A branch circuit. In any case, the continuous load fed by the workbench outlet receptacles must not exceed 80% of the rating of the branch circuit that feeds the workbench.
• Each workbench has proper seismic anchoring or other restraint against unintentional movement so that the cord-and-plug AC input power assembly is protected from damage resulting from tension, pinching, crushing, etc. (See PUB 3000, Chapter 23, Seismic Safety.)
• If the bench is fitted with a metallic or otherwise conductive work surface, the workbench wiring system is protected by an approved GFCI.