What 29 CFR 1910.334 requires (plain English)
29 CFR 1910.334 governs the use of electrical equipment as part of OSHA's electrical safety-related work practices: how portable tools, cords, and equipment must be handled and inspected so they do not shock or electrocute the worker. Damaged cords and tools are among the most common electrical hazards in any workplace: a cut cord, a missing ground pin, or internal damage from being run over or crushed can energize a metal tool or expose a live conductor. This standard puts the responsibility on the user to catch those defects before use.
The core requirement is pre-use inspection. Portable cord- and plug-connected equipment and flexible cord sets (extension cords) must be visually inspected before use on any shift for external defects (such as loose parts, deformed or missing pins, or damage to the outer jacket or insulation) and for evidence of possible internal damage. Any equipment or cord found damaged or defective must be removed from service, and no employee may use it until the necessary repairs and tests to render it safe have been made. This shift-by-shift check catches the everyday wear and damage that periodic testing alone would miss.
Handling and use rules complete the standard. Portable equipment must be handled in a manner that will not cause damage: flexible cords may not be used to raise or lower equipment, and may not be fastened with staples or otherwise hung in a way that could damage the outer jacket or insulation. Equipment must be connected and disconnected by the plug (not by pulling the cord), and used in accordance with its ratings and conditions of use. Together with the wiring standards (1910.305) and the de-energization work practices (1910.333), 1910.334 keeps the everyday use of electrical tools from becoming a shock hazard.