Conditions of Use

DOE-HDBK-1092-2004

8.3.2

CONDITIONS OF USE

Portable electric tools, equipment, and GFCIs shall not be used in hazardous locations unless

marked to indicate suitability for such use.

Portable electric tools and equipment shall not be handled or suspended by their cords. Tools

and equipment shall be used only for their intended purpose, and when guards are required,

such guards shall be in place and functional.

Tools and equipment shall be grounded via the case, double-insulated, specially approved low

voltage types, or self-contained, battery-operated.

Tools and equipment used in damp areas should be approved for such use. Generally, electrical

tools are not approved for use in wet or damp areas without other means of protection.

8.3.3

USE OF EXTENSION CORDS

Use of extension cords should be minimized. Such cords shall be suitable for the intended use,

such as waterproof connectors for wet or damp areas, and are subject to the same conditions

as the tool or equipment cord. Generally, daisy chaining of extension cord sets is prohibited

unless specifically allowed by the manufacturer and listed for this application.

Extension cords should be visually inspected before each use.

Extension cord sets used on construction sites and used with portable metal electric tools and

appliances shall be of three-wire type and shall be designed for hard or extra-hard usage.

Flexible cords used with temporary and portable lights shall be designed for hard or extra-hard

use. OSHA recognizes hard-service cord (types S, ST, SO, and STO) and junior-hard service

cord (types SJ, SJO, SJT, and SJTO) as suitable for extra-hard and hard use.

Note: Extension cords approved for outdoor use may be identified by "outdoor" or "W-A" on the

jacket.

Flexible cord sets shall be listed as an assembly by a national recognized testing laboratory

(See Section 2.5). Flexible cord sets used on construction sites shall contain the number of

conductors required for the circuit plus an equipment grounding conductor. The cords shall be

hard use or extra-hard use as specified in the NEC.

8.3.4

DOUBLE INSULATED TOOLS

The NEC references the use of double-insulated tools in UL Standard UL 1097, Double

Insulation Systems for Use in Electrical Equipment, which provides the requirements for

equipment marked "Double Insulation" or "Double Insulated." Since the end product standard

takes precedence, the end-product UL Standard should also be consulted when there are

questions pertaining to products that require double insulation.

Double insulation is a system comprised of two insulation systems (basic and supplementary)

that are physically separated and are not subjected to temperature, contaminants and other

deteriorating factors at the same time.

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