What arc welding and cutting safety requirements does 29 CFR 1926.351 set for construction sites regarding shielding and grounding return circuits? Answer in under 100 words. Cite only eCFR (www.ecfr.gov) sources.

Details / How it works

Shielding: Under § 1926.351(e), whenever practicable, all arc welding and cutting operations must be shielded by noncombustible or flameproof screens that protect employees and other persons working in the vicinity from the direct rays of the arc.

Ground returns: A ground return cable must have a safe current-carrying capacity equal to or exceeding the specified maximum output of the arc welding or cutting unit it services. A structure or pipeline may serve as a ground-return circuit only if the required electrical contact exists at all joints; any generation of arc, sparks, or heat rejects the structure as a ground circuit. When a structure or pipeline is continuously employed as a ground return, all joints must be bonded and periodic inspections conducted.

Numbers & thresholds

Exceptions & edge cases

• Pipelines containing gases or flammable liquids, and conduits containing electrical circuits, are prohibited as ground returns.
• For welding on natural gas pipelines, the technical portions of U.S. Department of Transportation regulations at 49 CFR part 192 apply.
• Where a structure or pipeline is continuously used as a ground return, bonding of joints plus periodic inspections ensure no condition of electrolysis or fire hazard arises.
• Shielding is required "whenever practicable," applying to protection of both workers and other persons near the operation.