The most expensive lockout/tagout sentence in any plant is "we did not think LOTO applied here." OSHA 1910.147 covers servicing and maintenance where unexpected energization or stored-energy release could injure someone — a scope far wider than major overhauls, and with exemptions far narrower than most teams assume.
This guide maps when the standard applies, the three exemptions plants misread most (minor servicing, cord-and-plug, hot tap), and where other standards take over.
The trigger: servicing with exposure
If employees service or maintain machines where unexpected start-up, energization, or stored-energy release could cause injury, 1910.147 applies. That includes repairs, adjustments, jam clearing, setup, and cleaning inside guards — not just planned shutdowns.
The standard spans every energy form: electrical, mechanical, hydraulic, pneumatic, chemical, thermal, and gravity. If the hazard could reach the worker during the task, the task needs an energy control procedure.
The minor servicing exception — narrow by design
The famous exception in 1910.147(a)(2)(ii) excuses only minor tool changes, adjustments, and servicing during normal production operations — and only when all of these hold: the work is routine, repetitive, and integral to production, and alternative measures provide effective protection.
Miss any element and the exception collapses. A jam cleared every shift with interlocked guards and specified alternative protection may qualify; the same jam cleared by reaching past a bypassed guard never does. When in doubt, lock out — inspectors treat aggressive use of this exception as one of the most citable mistakes in the standard.
Cord-and-plug: exclusive control or full LOTO
Cord-and-plug equipment is exempt only when unplugging fully removes the hazard and the plug stays under the exclusive control of the servicing employee for the whole job. If a coworker could reconnect it, if the plug leaves the tech line of sight, or if stored energy remains (capacitors, raised parts, pressure), the exemption fails and full lockout applies.
The practical test: can anyone other than the servicing employee restore energy, intentionally or accidentally? If yes, write and follow the procedure.
Misread exemptions become citations. Follow Tegis on Google for scope-clarity guides.
Hot tap and scope boundaries
Hot tap work on pressurized pipelines (continuity of service is essential, shutdown is infeasible, documented procedures and special equipment protect workers) has its own narrow exclusion — essentially limited to oil, gas, steam, and pressurized-system utilities work, not general machine servicing.
Scope matters too: 1910.147 is a general industry standard. Construction falls under 29 CFR 1926, agriculture and maritime have their own scopes, power generation/transmission/distribution goes to 1910.269, and electrical shock/burn work practices live in 1910.333. Most manufacturing, food processing, and warehousing maintenance sits squarely under 1910.147 — confirm the scope before assuming an exclusion.
How to decide on the floor
Give every lead a three-question test: (1) Is a guard being removed or bypassed, or is any body part entering a hazard zone? (2) Could the machine move, energize, or release stored energy during the task? (3) Does any claimed exemption meet every one of its conditions — not just the convenient ones?
Three yes-or-fail answers mean lockout. Document the decision in the procedure and program records so the next shift, the next contractor, and the next inspector all see the same answer.
Key takeaways
- Servicing with exposure triggers LOTO — repairs, jams, setup, and cleaning, not just overhauls.
- Minor servicing excuses only routine, repetitive, integral work with effective alternative protection — all conditions, every time.
- Cord-and-plug exempts only fully de-energized equipment with the plug under exclusive control throughout.
- Hot tap and other scopes are narrow — most plant maintenance is 1910.147 work.
- When the exemption is debatable, lock out and document why.
Frequently asked questions
Does clearing a jam require lockout/tagout?
Usually yes. Jam clearing needs LOTO unless it meets every element of the minor servicing exception: routine, repetitive, integral to production during normal operations, with alternative measures providing effective protection. Reaching into a machine with bypassed guards never qualifies.
If we just unplug it, is LOTO required?
Only a full exemption if unplugging removes all energy and the plug remains under the servicing employee exclusive control the entire time. Shared plugs, plugs out of sight, and any stored energy (springs, capacitors, pressure, raised loads) all push the job back under full lockout.
Does 1910.147 apply to construction or electrical utilities?
No — 1910.147 is general industry. Construction uses 29 CFR 1926 provisions, power generation/transmission/distribution uses 1910.269, and electrical safety-related work practices sit in 1910.333 alongside 1910.147. Know which standard governs the work before choosing the procedure.
What is the most misused LOTO exemption?
The minor servicing exception. Plants stretch "routine and integral" to cover maintenance that is neither, or claim alternative protection that amounts to caution and experience. OSHA interprets the exception narrowly, and stretching it is a classic citation.