Arc welding equipment requirements

Under 1926.351(a)(1) and 1926.351(a)(2) only manual electrode holders that are specifically designed for arc welding and cutting and that have insulation adequate for the maximum current and voltage encountered may be used. Employers must use holders that are rated to safely handle the maximum electrode current and must ensure that any current-carrying parts in the grip area and the outer jaw surfaces are fully insulated against the maximum voltage to ground (1926.351(a)(1) and 1926.351(a)(2)).

• Inspect holders for damage, correct rating, and insulation before use.
• Replace holders that are not specifically designed for welding or that show compromised insulation.

Reference: 1926.351(a).

Under 1926.351(b)(1) all arc welding and cutting cables must be completely insulated, flexible, and capable of handling the maximum current required for the job considering the welder's duty cycle. Use cables sized and insulated for the unit's maximum output and expected work pattern (1926.351(b)(1)).

• Match cable ampacity to the welding machine's rated current and the task's duty cycle.
• Use flexible, insulated welding cable rather than general-purpose cords.

Reference: 1926.351(b)(1).

Under 1926.351(b)(2) at least 10 feet of cable from the end connected to the electrode holder must be free of repairs or splices, except when the cable uses standard insulated connectors or splices whose insulating quality equals that of the cable. In those permitted cases, connectors or equal-quality splices are acceptable within the 10-foot zone (1926.351(b)(2)).

• If you must splice near the holder, use factory-standard insulated connectors or splices that match the cable insulation.
• Avoid makeshift splices or exposed metal in the first 10 feet from the holder.

Reference: 1926.351(b)(2).

Under 1926.351(b)(3) when you join cable lengths you must use substantial insulated connectors with a capacity at least equal to the cable; if you use cable lugs they must be tightly fastened for good electrical contact and any exposed metal on the lugs must be completely insulated. Proper connectors and secure mechanical and electrical connections are required (1926.351(b)(3)).

• Use connectors rated for the cable ampacity.
• Ensure exposed metal is fully insulated after installation.

Reference: 1926.351(b)(3).

Under 1926.351(b)(4) cables needing repair must not be used; however, if a cable (other than the 10-foot lead) is worn so that bare conductors are exposed, the exposed portion must be protected by rubber and friction tape or equivalent insulation. In short: do not use damaged cables unless the exposed conductors are properly re-insulated with equivalent protection (1926.351(b)(4)).

• Remove from service cables with major damage until they are repaired by qualified personnel.
• For localized wear (not the 10-foot electrode-lead zone), re-cover with rubber and friction tape or equivalent insulation.

Reference: 1926.351(b)(4).

Under 1926.351(c)(1) a ground return cable must have a current-carrying capacity equal to or greater than the welding unit's maximum output capacity, and under 1926.351(c)(2) pipelines containing gases or flammable liquids and conduits with electrical circuits must not be used as a ground return. Use a dedicated, adequately sized ground return cable rather than piping or live conduits (1926.351(c)(1) and 1926.351(c)(2)).

• Size the ground return to at least the welding unit's rated maximum output.
• Never clamp a ground to a pipeline carrying gas or flammable liquid or to energized conduits.

Reference: 1926.351(c)(1) and 1926.351(c)(2).

Under 1926.351(c)(2) when welding on natural gas pipelines, the technical portions of the Department of Transportation's pipeline safety rules at 49 CFR part 192 apply in addition to OSHA requirements. Employers must follow DOT pipeline safety technical rules as specified for welding on natural gas pipelines (1926.351(c)(2)).

• Coordinate welding procedures with pipeline owners/operators and follow applicable DOT requirements.
• Confirm the appropriate bonding/grounding plan consistent with pipeline safety rules.

Reference: 1926.351(c)(2) and 49 CFR part 192.

Under 1926.351(c)(3) and 1926.351(c)(4) if you use a structure or pipeline as a ground return you must verify continuous electrical contact at all joints (no arcing, sparking, or heat) and, when used continuously, bond all joints and periodically inspect to ensure no electrolysis or fire hazard develops. If arcing or heating occurs at any joint the structure or pipeline must not be used as the ground circuit (1926.351(c)(3) and 1926.351(c)(4)).

• Check joints for solid electrical continuity before relying on a structure as ground.
• If used long-term, bond joints and set up scheduled inspections for electrolysis and fire hazards.

Reference: 1926.351(c)(3) and 1926.351(c)(4).

Under 1926.351(c)(5) the frames of all arc welding machines must be grounded either through a third wire in the cable containing the circuit conductor or through a separate grounded wire at the power source, and under 1926.351(c)(6) all ground connections must be inspected to ensure they are mechanically strong and electrically adequate for the required current. Ground connections must be secure and capable of carrying the welding current (1926.351(c)(5) and 1926.351(c)(6)).

• Use a third-wire grounding conductor or an equivalent separate grounded conductor.
• Inspect clamps and bonding points for corrosion, tightness, and full contact before each job.

Reference: 1926.351(c)(5) and 1926.351(c)(6).

Under 1926.351(c) grounding circuits not relying on the structure should be checked to ensure the circuit resistance between ground and the grounded power conductor is low enough to let sufficient current flow to trip the fuse or breaker. In other words, test the ground path so that overcurrent protection will operate in a fault (1926.351(c)).

• Use resistance or continuity testing appropriate for the system to verify a low-resistance ground.
• Correct any high-resistance or intermittent connections that could prevent proper protective-device operation.

Reference: 1926.351(c).

Under 1926.351(d)(1) when electrode holders are to be left unattended the electrodes must be removed and the holders placed or protected so they cannot make electrical contact with employees or conducting objects. Remove electrodes and secure holders to prevent accidental contact (1926.351(d)(1)).

• Take electrodes out of holders and store holders on nonconductive surfaces or in racks.
• Ensure holders cannot fall onto conductive materials or touch people.

Reference: 1926.351(d)(1).

Under 1926.351(d)(2) hot electrode holders must not be dipped in water because doing so may expose the welder or cutter to electric shock; dipping a live or recently used holder in water can create a conductive path to the operator. Do not immerse hot holders in water (1926.351(d)(2)).

• Let holders cool in a safe, nonconductive place; do not use water to cool or quench powered holders.
• Train employees that water contact with live electrical equipment is a shock hazard.

Reference: 1926.351(d)(2).

Under 1926.351(d)(3) when an arc welder or cutter leaves work for an appreciable time or when the welding machine is to be moved, the power supply switch to the equipment must be opened. Turn off the equipment at the power supply before leaving or moving it (1926.351(d)(3)).

• Switch off the power supply, remove electrodes if applicable, and secure equipment before relocation.
• Lockout/tagout procedures may also apply for equipment movement or maintenance.

Reference: 1926.351(d)(3).

Under 1926.351(d)(4) employees must report any faulty or defective equipment to their supervisor. Prompt reporting is required so defective equipment can be removed or repaired to prevent hazards (1926.351(d)(4)).

• Tag out and remove defective welding machines, cables, or holders until repaired.
• Supervisors should ensure timely repair by qualified personnel.

Reference: 1926.351(d)(4).

Under 1926.351(c)(1) if a single ground return cable serves more than one unit its safe current-carrying capacity must equal or exceed the total specified maximum output capacities of all units it serves. Size the cable to carry the combined maximum outputs of every connected machine (1926.351(c)(1)).

• Calculate the sum of the maximum outputs of all units on the ground return and choose cable rated accordingly.
• Consider duty cycle and continuous loads when selecting cable size.

Reference: 1926.351(c)(1).

Under 1926.351(b) good practices include using completely insulated flexible cables sized for the job, keeping the first 10 feet from the electrode holder free of splices unless approved insulated connectors are used, using substantial insulated connectors for splices, and not using cables in need of repair or protecting exposed conductors with equivalent insulation. Follow these rules to reduce shock and fire hazards from welding cables (1926.351(b)(1)-(4)).

• Routinely inspect cables for wear, cuts, or exposed conductors.
• Replace or repair damaged cables with proper insulated connectors or equivalent insulation.

Reference: 1926.351(b).

Under OSHA requirements employers must assess the workplace to determine hazards and select appropriate PPE for welding tasks; this assessment must be conducted by the employer and documented in writing when PPE is required. The PPE hazard-assessment interpretation clarifies that employers must evaluate hazards before selecting PPE and may use the guidance in 29 CFR 1910.132(d) and Appendix B for selection processes (PPE hazard assessment LOI and 1926).

• Perform a task-specific hazard assessment for eye, face, hand, and body protection, plus respiratory protection as needed.
• Keep a written certification of the hazard assessment when PPE is required per 29 CFR 1910.132(d)(1).

References: PPE hazard assessment LOI and 1926.

Under 1926.351 and OSHA's PPE hazard assessment guidance employers must consider respiratory protection for welding when the hazard assessment shows welding fumes or gases could exceed permissible limits or present a respiratory hazard. Employers must evaluate exposures and select respirators according to the respiratory protection standard if needed (1926 and PPE hazard assessment LOI at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28).

• Conduct exposure monitoring or a competent-hypothesis assessment for fumes and gases.
• If respiratory protection is required, comply with 29 CFR 1910.134 for fit testing, training, and program elements.

References: 1926 and PPE hazard assessment LOI.

Under 1926.351(b)(3) any exposed metal parts of cable lugs used for welding connections must be completely insulated after fastening, so no exposed conductive metal remains that could contact people or other conductors. Ensure you fully cover lug surfaces with equivalent insulating material (1926.351(b)(3)).

• Use heat-shrink tubing, molded insulated covers, or equivalent rated insulation on lugs.
• Verify insulation integrity after installation and during inspections.

Reference: 1926.351(b)(3).

Under 1926.351(d) employers must instruct employees in safe means of arc welding and cutting including: proper handling and placement of electrode holders when unattended, never dipping hot holders in water, powering down equipment before leaving or moving it, and reporting faulty equipment. Provide practical training on these specific operating instructions (1926.351(d)(1)-(4)).

• Train on inspection of cables, holders, and ground connections.
• Include stop-work, reporting procedures, and any site-specific grounding rules.

Reference: 1926.351(d).

Under 1926.351(c)(6) if a ground connection is mechanically loose or electrically inadequate you must repair or replace it so it becomes mechanically strong and electrically adequate for the required current; do not use equipment until ground connections meet this requirement (1926.351(c)(6)).

• Tighten, clean, and properly bond the connection or replace clamps or conductors as needed.
• Re-test the ground connection after corrective actions to confirm adequacy.

Reference: 1926.351(c)(6).