Hand and portable power equipment

You may make cord- and plug-connected portable equipment safe by using one of three options listed in 1926.956(b).

• Equip the tool with a cord that contains an equipment grounding conductor, bonded to the equipment frame and to a means for grounding at the other end (unless introducing a ground would increase the hazard) — see 1926.956(b)(1).
• Use double-insulated equipment that conforms to Subpart K — see 1926.956(b)(2).
• Connect the equipment through an isolating transformer whose ungrounded secondary is not more than 50 volts — see 1926.956(b)(3).

Choose the option that fits the tool, the work environment, and does not itself create a greater hazard.

You must not use the grounding conductor option when introducing a ground into the work environment would increase the hazard to an employee, because 1926.956(b)(1) allows that option only if it does not increase hazard.

• Examples where grounding could increase hazard include environments where grounding would create an unintended current path through workers or where specialized insulated equipment is required around energized conductors.
• If grounding would increase the risk, use the double-insulated equipment option or an isolating transformer.

Also perform a workplace hazard assessment before selecting controls; see OSHA's guidance on employer hazard assessments in the PPE hazard assessment Letter of Interpretation.

A double-insulated tool is acceptable when it is constructed so users are protected from electrical shock by two independent layers of insulation rather than relying on a ground, and that option is allowed by 1926.956(b)(2).

• Double-insulated tools must conform to the electrical safety requirements in Subpart K of Part 1926; see 1926.302(a).
• Use double-insulated tools where grounding is impractical or could increase hazard, or when the manufacturer certifies the tool as double-insulated.

You can use an isolating transformer to supply cord- and plug-connected equipment if the transformer has an ungrounded secondary that is not more than 50 volts, as allowed by 1926.956(b)(3).

• The isolating transformer must isolate the energized secondary from the primary and the grounded system so the secondary is effectively ungrounded and limited to 50 volts or less.
• Use this option when grounding the tool would increase hazard or when double-insulation is not available.

A portable or vehicle-mounted generator may only supply equipment located on the generator or the vehicle and cord- and plug-connected equipment through receptacles mounted on the generator or vehicle, in accordance with 1926.956(c)(1).

• Do not use a portable or vehicle-mounted generator to supply distant, separate work sites unless those connections are through receptacles on the generator or vehicle itself.
• This restriction helps ensure grounding and bonding requirements described in 1926.956(c)(2)–(4) are maintained.

You must bond the non-current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles to the generator frame, per 1926.956(c)(2).

• That means the equipment chassis and the grounding terminals are connected to the common generator frame so a fault will be carried safely to the frame.
• For vehicle-mounted generators, also bond the generator frame to the vehicle frame as required by 1926.956(c).

For vehicle-mounted generators, you must bond the frame of the generator to the vehicle frame so they are at the same electrical potential, as required by 1926.956(c).

• This bonding supports proper grounding and fault clearing for receptacles mounted on the generator or vehicle.
• Also ensure receptacle grounding terminals and non-current-carrying metal parts are bonded to the generator frame, as stated in 1926.956(c)(2).

You must bond any neutral conductor to the generator frame when a neutral conductor exists on the generator, as required by 1926.956(c)(4).

• Bonding the neutral to the frame ties the neutral to the generator chassis for correct fault-clearing characteristics; this is typically done at the generator's service equipment or as specified by equipment design.
• Ensure bonding is done following the generator manufacturer's instructions and applicable electrical codes while keeping the requirements of 1926.956(c) in mind.

Hydraulic fluid used in insulating sections of hydraulic tools is not subject to the general prohibition in paragraph (d)(1) of 1926.302, meaning hydraulic fluid can be used for insulation where designed and installed as insulating sections of the tool, per 1926.956(d)(1).

• This applies only to the insulating portions of the tool specifically designed for electrical insulation.
• Always follow the tool manufacturer's specifications and maintain insulating sections to preserve their insulating properties.

You may not exceed the safe operating pressures for hydraulic and pneumatic tools, hoses, valves, pipes, filters, and fittings, and if any hazardous defects are present the equipment may not be used, as stated in 1926.956(d)(2).

• The note clarifies that if defects exist, no operating pressure is safe; in the absence of defects, the manufacturer-rated maximum operating pressure is the maximum safe pressure.
• Regularly inspect and maintain equipment and replace parts when defects are found to ensure pressures stay within safe limits.

A hydraulic or pneumatic tool used where it may contact exposed energized parts must be designed and maintained for such use, as required by 1926.956(d)(3).

• This means insulating properties, clearances, and materials must be appropriate for the voltage and conditions involved.
• Employers should follow manufacturers' guidance, perform a hazard assessment, and document that tools are appropriate for work near energized parts; see OSHA's PPE hazard assessment Letter of Interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28 for employer assessment guidance.

The hydraulic system supplying a hydraulic tool that may contact exposed live parts must provide protection against loss of insulating value due to formation of a partial vacuum in the hydraulic line, as required by 1926.956(d)(4).

• Practical protections include check valves, air eliminators, or system designs that prevent cavitation or vacuum in the line.
• Note: the standard warns that hydraulic lines without check valves and with more than 10.7 meters (35 feet) separation between the oil reservoir and the upper end of the system promote partial vacuum formation; implement design changes to avoid that condition.

Pneumatic tools used on energized electric lines or where they may contact exposed live parts must provide protection against accumulation of moisture in the air supply, per 1926.956(d)(5).

• Use moisture separators, air dryers, filters, or properly located supply sources to keep the air dry.
• Dry air prevents electrical tracking and maintains insulating properties of components that could otherwise become conductive when wet.

Pressure must be released before connections are broken unless quick-acting, self-closing connectors are used, as required by 1926.956(d)(6).

• Releasing pressure prevents sudden ejection of fluid or parts and reduces injury risk.
• If using quick-acting connectors, ensure they are maintained and rated for the system pressure and application.

No; employers must ensure employees do not use any part of their bodies to locate or attempt to stop a hydraulic leak, as stated in 1926.956(d)(7).

• Use appropriate tools like cardboard, paper, or manufacturer-recommended devices to detect leaks, and depressurize the system before repairs.
• This prevents injection injuries and serious tissue damage from high-pressure fluid leaks.

Hoses may not be kinked when used with hydraulic or pneumatic tools, as required by 1926.956(d)(8).

• Kinking weakens hoses, restricts flow, increases pressure in parts of the system, and can lead to failure.
• Route, support, and inspect hoses so they remain free of kinks and replace hoses that show damage or deformation.

Any neutral conductor must be bonded to the generator frame and non-current-carrying metal parts and grounding terminals must be bonded to the generator frame, per 1926.956(c)(2)–(4).

• Bond the generator frame to the vehicle frame for vehicle-mounted units (see 1926.956(c)).
• Proper bonding ensures faults are carried to a common point for safe clearing and prevents differences in potential between equipment frames.

Cord- and plug-connected equipment that is not covered by Subpart K must follow one of the alternatives in 1926.956(b) instead of complying with 1926.302(a)(1).

• In other words, where 1926.956 applies, you may meet its specific grounding/double-insulation/isolating transformer options instead of following the default in 1926.302(a)(1).
• Confirm whether the equipment is covered by Subpart K; if it is, follow Subpart K requirements; if not, follow 1926.956's options.

The employer is responsible for ensuring hydraulic and pneumatic tools are operated within safe pressures and are free of hazardous defects, as required by 1926.956(d)(2).

• Employers should follow manufacturers' rated operating pressure and perform regular inspections and maintenance.
• Employers should also perform hazard assessments to decide appropriate controls and PPE; see OSHA's PPE hazard assessment Letter of Interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28 for guidance on employer assessment duties.

A separation of more than 10.7 meters (35 feet) between the oil reservoir and the upper end of the hydraulic system promotes formation of a partial vacuum if the hydraulic line lacks check valves, as noted in 1926.956(d)(4).

• To prevent vacuum formation, use check valves, redesign the system layout, or provide other protective measures required by 1926.956(d)(4).

Employers should install moisture separators, air dryers, filters, and properly maintain air supply systems so pneumatic tools used on or near energized parts do not accumulate moisture, satisfying 1926.956(d)(5).

• Regularly inspect and drain air compressors and receivers, install in-line filters and separators, and perform maintenance to prevent moisture buildup.
• Document the air supply maintenance program and include it in the employer's hazard assessment as described in OSHA's PPE hazard assessment Letter of Interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28.