Lockout/Tagout Verification: OSHA Rules, Try-Out, and Group Jobs

Lockout/tagout verification is the step where the authorized employee performing maintenance personally confirms, at the point of work, that every energy source feeding the machine has been isolated and that the equipment cannot start. Under 29 CFR 1910.147, this confirmation has two parts: a measurement with an instrument matched to the energy type, and an attempted start using the machine’s normal operating controls. Both are required, and neither substitutes for the other.¹

Who Has to Do the Verification

Only an authorized employee can verify isolation. OSHA defines an authorized employee as the person who locks or tags out the equipment to service or maintain it. That is different from an affected employee, who operates the machine or works near it but is not the one performing the maintenance.¹

The rule puts the check in the hands of the person who will be exposed. A supervisor cannot verify on behalf of the worker who is about to reach into the machine. A coworker from a different crew cannot do it either. The authorized employee doing the servicing verifies isolation personally, every time.¹

Before anyone qualifies as an authorized employee, they need training on recognizing the hazardous energy sources present, understanding the type and magnitude of that energy, and applying the specific isolation and control methods used at the facility. Employers must certify that training and keep records showing each employee’s name and training dates.¹

What Must Already Be Done Before You Verify

Verification is the last step of the energy control sequence in 29 CFR 1910.147(d). If any earlier step is skipped or reordered, the verification itself becomes meaningless. Before you check for a zero-energy state, all of the following must have happened, in order:

The authorized employee has identified every energy source connected to the machine and understands the type, magnitude, and control method for each.
The machine has been shut down using its normal stopping procedure.
Every energy isolating device needed to cut the machine off has been located and operated.
A lockout or tagout device has been attached to each isolating device by the authorized employee.
All residual or stored energy has been relieved, disconnected, or restrained.

Verification is what closes the loop on those five steps. It is your proof that they actually worked.¹

How to Verify: Instrument Test, Then Try-Out

Verification has two components. Both are required. One does not replace the other.

Test the Right Instrument on the Right Energy

Match the instrument to the energy type. Electrical circuits get checked with a rated voltage tester, phase-to-phase and phase-to-ground, at the point of work. Every phase conductor is tested, not only the one you assume is hot. Hydraulic and pneumatic systems are verified with pressure gauges reading zero. Mechanical isolation is confirmed visually: disconnect switches open, pins seated, blocking devices in position.

A critical practice at this step is checking that your test instrument itself works before and after the reading. NFPA 70E calls it “absence of voltage” testing. You confirm the meter reads correctly on a known live source, take the measurement on the isolated circuit, and then re-confirm the meter on the known live source afterward. A zero reading from a dead meter looks identical to a zero reading on a truly dead circuit, and that confusion has killed workers.

Try to Start the Machine

After the instrument check, the authorized employee operates the machine’s normal start controls to attempt to run it. This is the true test. If the isolation failed anywhere upstream, the try-out reveals it before anyone puts hands inside the equipment. Before pressing the start button, the employee first confirms that no one is positioned where an unexpected start would injure them.¹

When the machine does not respond, which is the expected result, the operating controls must be returned immediately to the off or neutral position. This detail matters more than it looks. If the start control is left engaged and someone later removes the lockout device, the machine will energize instantly with no warning. Returning the controls to neutral adds one more layer of protection against a sequencing mistake during re-energization.¹

Stored Energy and Verification That Doesn’t End

Isolating the source is not enough on its own. After locks or tags go on, any stored or residual energy must be relieved, disconnected, or restrained before you verify. That means capacitors holding a charge, springs under tension, elevated components that could fall, pressurized hydraulic or pneumatic lines, and thermal energy in heated systems. Each type has its own dissipation method: bleeding lines, grounding capacitors, lowering suspended parts, blocking components that could shift.¹

Some systems can reaccumulate stored energy to hazardous levels after the initial dissipation. When that is possible, verification of isolation must continue throughout the entire servicing period, not only at the start. This is where complacency shows up. The first verification looked clean, so people assume the state holds. With systems prone to reaccumulation, such as certain hydraulic setups or thermal processes, periodic re-checking is not optional.¹

Group Jobs: Everyone Still Verifies Personally

When a crew, department, or other group services the same equipment, 29 CFR 1910.147(f)(3) requires a group lockout procedure giving each worker protection equivalent to a personal lockout device. A primary authorized employee takes responsibility for the overall energy control and leads the verification process for the group.²

The usual mechanism is a group lockbox. Keys controlling the primary isolation devices go inside, and each authorized employee attaches a personal lock to the box before starting work. No one can retrieve the keys and re-energize the machine until every worker has removed their individual lock. Each employee still retains personal responsibility for verifying the machine is safe before attaching a lock and starting their task.²

Shift Changes Without Gaps

Maintenance work that runs across shifts creates a window where protection can lapse during the handoff. Under 29 CFR 1910.147(f)(4), the employer must have procedures ensuring orderly transfer of lockout or tagout protection between off-going and oncoming employees, with no gap in coverage. In practice, the incoming employee applies their lock before the outgoing employee removes theirs, so the equipment is never left unprotected. The oncoming worker then performs their own verification before beginning the task.¹

Tagout Instead of Lockout

If an employer uses tagout on a device that is capable of being locked out, OSHA imposes a higher burden. The employer must show that the tagout program provides safety equivalent to a lockout program. That means attaching the tag where a lock would go and adding measures such as removing a circuit element, blocking a switch, opening an extra disconnect, or removing a valve handle. A tag on its own is a warning; it does not physically stop someone from flipping a switch, which is why tagout-only programs get more scrutiny and why verification still has to prove a genuine zero-energy state, not just the presence of a tag.¹

What Skipping or Botching Verification Can Cost

Lockout/tagout violations consistently rank among OSHA’s most frequently cited standards. As of 2025, the maximum penalty for a serious violation is $16,550 per violation, and willful or repeated violations carry a maximum of $165,514 per violation. These amounts are adjusted annually for inflation.³

OSHA can cite each instance of noncompliance separately: every machine missing a written procedure, every untrained authorized employee, every missing inspection record. A single audit that turns up systemic gaps across multiple machines can generate stacked penalties quickly. Current training certifications, documented procedures for each piece of equipment, and evidence that verifications are actually being performed as written are the practical defense during an inspection.¹

1
Occupational Safety and Health Administration. 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout/Tagout)
2
eCFR. 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout/Tagout)
3
Occupational Safety and Health Administration. 2025 Annual Adjustments to OSHA Civil Penalties