Answer Library / Lockout/Tagout OSHA letter · 2024-10-21

Can a machine be re-energized during servicing when the task requires power?

Quick answer

Yes, but only temporarily and under strict conditions. OSHA permits temporary removal of lockout/tagout devices and re-energization when necessary for tasks that require power — such as testing or positioning — if the employer follows the sequential steps in the standard and provides alternative protection like machine guarding (29 CFR 1910.147(f)(1)). OSHA does not recognize the 'alternative methods' definitions in ANSI B11.0-2020 and ANSI Z244.1-2016, or the 'feasibility' definition in ANSI B11.0-2020, as substitutes for compliance.

A consultant explained that clients must perform some service and maintenance tasks that require power — for example, machine setup for product changeovers that cannot be performed with the primary energy source isolated and locked out, but that still require control functions like inch and jog operations. The consultant asked whether OSHA offers alternatives to isolating and locking out primary energy sources in those circumstances.

OSHA responded that the standard already provides a pathway: 29 CFR 1910.147(f)(1) permits temporary removal of LOTO devices and re-energization when 'necessary to perform particular tasks that require energization,' provided the employer supplies alternative employee protection, such as machine guarding techniques when it is not possible to remove employees from the danger area. Before re-energizing, the employer must follow a specific sequence: clear the machine of tools and materials (1910.147(e)(1)); remove employees from hazardous areas (1910.147(e)(2)); remove the lockout/tagout devices (1910.147(e)(3)); energize and use effective employee protection during testing or positioning; and then re-isolate, de-energize, and reapply devices if servicing continues (1910.147(d)). The exception applies only for the limited time required for testing or repositioning — once energization is no longer necessary, energy control measures must resume.

OSHA declined to endorse the consensus-standard framework the inquirer proposed. The agency acknowledged that ANSI B11.0-2020 and ANSI Z244.1-2016 offer 'useful guidance,' but it has not determined that compliance with those standards constitutes compliance with OSHA requirements — only national consensus standards formally adopted or incorporated into OSHA standards satisfy Section 5(a)(2) of the OSH Act. OSHA also rejected the ANSI B11.0-2020 'feasibility' definition, pointing instead to its Field Operations Manual (CPL 02-00-164, 2020), which defines feasibility as abatement measures 'capable of being done,' with technical feasibility tied to available know-how and economic feasibility tied to the employer's financial ability — noting that economic infeasibility claims will not be accepted if the rest of the industry complies at a significantly higher level.

The letter closes with a reminder that State Plan states may enact requirements more stringent than Federal OSHA's and should be consulted for jurisdiction-specific guidance.

29 CFR 1910.14729 CFR 1910.147(f)(1)29 CFR 1910.147(e)(1)29 CFR 1910.147(e)(2)29 CFR 1910.147(e)(3)29 CFR 1910.147(d)
Source: OSHA Standard Interpretation letter, 2024-10-21 — read the official letter on osha.gov →
Interpretation letters explain how OSHA applies its rules to specific situations. Always verify current requirements — regulations and enforcement policies change.

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