Guidance
Extension Cords: 5 Things to Know
Extension Cords: 5 Things to Know
- OSHA
- Guidance
- OSHA 4495
- Unknown
- Electrical Safety
- Electric shockElectrical safety
- Inspection and maintenance
- Construction
Summary
Five precautions address extension-cord selection, grounding, service ratings, strain relief and ongoing inspection. The sheet explains moisture-related current leakage and conductor damage, recommends watertight or sealable connectors, and suggests considering a portable GFCI. Damaged, modified or inadequately rated cords must be withdrawn immediately.
Classifications: Electric shock; electrocution.
Classifications: Electrical safety; electrical hazards.
Classifications: Inspection and maintenance; asset inspection; equipment maintenance.
Classifications: Construction; construction industry.
Summary
This guidance gives five precautions for selecting, using, inspecting and maintaining extension cords.
OSHA 4495. Themes: electrical safety.
EXTENSION CORDS 5 THINGS TO KNOW
Use factory-assembled cord sets.
1 They provide quality assurance and manufacturing standards to keep workers safe. The sets often have warranties and other guarantees.
Use only extension cords that are 3-wire type. Extension cords must be 3-wire type to be grounded and permit grounding of any tools or equipment connected to them. A wet cord connector, especially if damaged or improperly sealed, allows electric current to escape from the live parts of the connector. Workers can be impacted if they touch the connector or a grounded object. a Leakage can occur not
2 just on the face of the connector, but at any wet surface on the equipment. Limit excessive moisture exposure of connectors and tools by using watertight or sealable connectors and consider using a portable GFCI.
Use only extension cords that are marked with a designation code for hard or extra-hard usage.
3 The OSHA construction standard requires flexible cords to be rated for hard or extra- hard usage. Examples of these codes are S, ST, SO, and STO for hard service, and SJ, SJO, SJT, and SJTO for junior hard service.
Use only cords, connection devices, and fittings that are equipped with strain relief and remove cords from receptacles by pulling on the plugs, not the cords.
4 Flexible cords must connect to devices and to fittings in ways that prevent tension at joints and terminal screws. Straining a cord can cause the strands of one conductor to loosen and touch another conductor.
Continually inspect cords on-site. Any cords not marked for hard or extra-hard use, or which have been damaged or modified, must be removed from service immediately. A flexible cord may be
5 damaged by door or window edges, by staples and fastenings, by abrasion from adjacent materials, or simply by aging. If the electrical conductors become exposed, there is a danger of shocks, burns, or fire.
OSHA 4495-02 2026
• OSHA.gov/electrical • 1-800-321-OSHA (6742)