A compliant lockout/tagout equipment list under OSHA 29 CFR 1910.147 includes safety padlocks, hasps, group lockboxes, circuit breaker lockouts, plug lockout boxes, valve lockouts (ball, gate, and butterfly), cable lockouts, chains, wedges, key blocks, adapter pins, blank flanges, and warning tags attached with rated self-locking fasteners. Every one of those devices must meet four performance standards before it counts as compliant hardware.
The Four Requirements Every Device Must Meet
Under 29 CFR 1910.147(c)(5), every lockout and tagout device in your facility has to satisfy four baseline requirements. Hardware that fails any of them exposes you to citations no matter what you paid for it.1Occupational Safety and Health Administration. Lockout-Tagout eTool – Tutorial – Materials and Hardware
- Durable. Devices have to survive the environment where they’re used for as long as they’re needed. The standard specifically calls out acid and alkali exposure as conditions that cannot degrade the device.
- Standardized. All lockout and tagout devices across the facility must be uniform in at least one characteristic: color, shape, or size.
- Substantial. Lockout devices must resist removal without excessive force or specialized cutting tools like bolt cutters. Nobody should be able to casually pull off a lock.
- Identifiable. Every device must clearly show who applied it, so that only the authorized worker can remove it.
Read the rest of this list with those four rules in mind. They apply to a simple padlock and to a complex cable lockout equally.
Safety Padlocks
The padlock is the core of any lockout program. Safety padlocks made for lockout use typically have non-conductive bodies to reduce electrical shock risk, come in bright standardized colors, and include writable labels where the authorized employee’s name is recorded.
Keys and padlocks must stay under the exclusive control of the authorized employee who applied them. A 1995 OSHA interpretation letter is direct on this: a master key or duplicate key is not an acceptable way to remove someone else’s padlock from an energy-isolating device. That rules out spare keys at the supervisor’s desk and identical keys shared across a crew.2Occupational Safety and Health Administration. 29 CFR 1910.147 – Interpretation on the Control of Hazardous Energy (Lockout/Tagout) Standard
Most facilities use keyed-different systems, where every authorized employee carries a unique key that opens only their own lock. Steel shackles handle heavy-duty environments and resist tampering. Aluminum shackles work better where weight or spark risk is a concern. Dielectric shackles are made entirely of non-conductive material for work inside electrical panels.
Hasps and Group Lockboxes
When multiple workers service the same machine, one lockout point has to hold everyone’s padlock. A lockout hasp is a hinged steel plate with multiple holes, each sized for one padlock. You clamp it over the energy-isolating device, and every authorized worker attaches their own lock. The machine cannot be re-energized until the last person removes their padlock.
OSHA requires this exact arrangement for group lockout: each authorized employee must affix a personal lockout device to the group lockout device, group lockbox, or comparable mechanism when they begin work, and remove it when they stop.3Occupational Safety and Health Administration. Group Lockout or Tagout
When the job involves multiple crews or departments, a primary authorized employee must take overall responsibility for coordinating lockout across all affected workers. That coordinator tracks who is working, manages continuity through shift changes, and verifies exposure status before any locks come off.4Occupational Safety and Health Administration. 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout/Tagout)
Group lockboxes work on the same principle. The key controlling the main lockout device goes inside a locked box, and each worker adds their own padlock to the box. Nobody accesses the master key until every personal lock is gone.
Circuit Breaker and Plug Lockouts
Electrical systems need their own hardware because breakers and plugs come in too many configurations for a padlock alone.
Circuit Breaker Lockouts
These clamp-on devices fit over a breaker toggle and physically prevent it from being switched on. They come in single-pole and multi-pole versions. The device usually attaches with a thumbscrew that tightens over the toggle and then accepts a padlock through a built-in hasp. Without a device matched to your breaker type, you can’t achieve reliable lockout on electrical panels.
Plug Lockout Devices
For equipment that plugs into a wall outlet, plug lockout boxes enclose the entire plug inside a rigid shell. They come in cylindrical and rectangular shapes to fit different cord sizes. Once the plug is inside and the box is locked, the equipment cannot be connected to power. This is simpler than tracing a machine’s circuit back to the breaker panel, which is why it’s common for portable equipment and smaller machines.
Valve Lockouts
Pressurized piping carries mechanical energy that can be as deadly as electricity. Valve lockouts hold a valve in the closed position so liquids, gases, or steam cannot flow to the equipment being serviced.
- Ball valve lockouts fit over the valve handle and lock it in the off position. Ball valves appear everywhere in industrial piping, which makes these among the most common devices.
- Gate valve lockouts are circular covers that wrap around the valve stem and prevent the handwheel from turning. Gate valves are slow-operating and often found on larger lines.
- Butterfly valve lockouts clamp onto the lever handle and prevent rotation. Some versions handle both lever-operated and gear-operated butterfly valves.
The device has to match the valve type, size, and handle configuration precisely. A device that doesn’t fit snugly can be defeated.
Cable Lockouts, Chains, and Other Securing Hardware
Not every energy source fits a purpose-built device. OSHA recognizes this and requires employers to supply locks, tags, chains, wedges, key blocks, adapter pins, self-locking fasteners, and other hardware for isolating, securing, or blocking machines from energy sources as needed.4Occupational Safety and Health Administration. 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout/Tagout)
Cable Lockouts
These use a flexible steel or coated nylon cable threaded through multiple lockout points, then cinched down with a locking mechanism. They are the go-to solution for oversized equipment, irregularly shaped valve handles, or situations that call for locking out several energy sources with one run of cable. The cable loops through each isolation point and accepts a padlock at the locking end.
Chains, Wedges, Key Blocks, and Adapter Pins
Chains do a similar job to cable lockouts and give greater strength for heavy-duty work. A chain threaded through a valve handwheel or around a switch mechanism and secured with a padlock can immobilize equipment too large for standard devices. Wedges physically block moving parts from shifting into a dangerous position. Key blocks fill a keyway or control slot so a switch cannot be operated. Adapter pins bridge the gap when an energy-isolating device lacks a built-in lockout hole, giving you a point to attach a padlock.
Blank Flanges
For piping systems carrying steam, natural gas, or other hazardous substances, blank flanges (also called blinds) provide isolation by inserting a solid metal plate between pipe flanges to block flow physically. An OSHA interpretation letter notes that blanking and blinding are among the techniques recognized for isolating flowable materials, particularly in permit-required confined space situations where standard valve lockout alone may not eliminate the hazard.5Occupational Safety and Health Administration. The Lockout/Tagout Standard
Warning Tags and Fastener Requirements
Tags are the informational counterpart to physical locks. Even when a machine is padlocked, a tag communicates why the equipment is shut down and who is responsible.
Tags must warn against hazardous conditions and carry a legend such as “Do Not Start,” “Do Not Open,” “Do Not Close,” “Do Not Energize,” or “Do Not Operate.” Each tag must also identify the authorized employee who applied it and describe the maintenance status of the equipment.1Occupational Safety and Health Administration. Lockout-Tagout eTool – Tutorial – Materials and Hardware
Tag construction and printing has to withstand weather, wet or damp locations, and corrosive environments like acid or alkali storage areas without falling apart or becoming unreadable.4Occupational Safety and Health Administration. 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout/Tagout)
The fastener that attaches the tag has its own rule. It must be non-reusable, attachable by hand, self-locking, and have a minimum unlocking strength of at least 50 pounds. The standard describes the baseline as being at least equivalent to a one-piece, all-environment-tolerant nylon cable tie. In practice, that means heavy-duty zip ties rated to the 50-pound threshold. Anything weaker or reusable does not comply.1Occupational Safety and Health Administration. Lockout-Tagout eTool – Tutorial – Materials and Hardware
When Tags Can Be Used Without Locks
Tags are not interchangeable with locks. OSHA strongly favors lockout because a lock is a physical barrier and a tag is only a warning. A tag does not stop anyone from flipping a switch.
Tagout alone is permitted in two situations. First, if the energy-isolating device is physically incapable of being locked out (some older valves and switches lack a built-in lockout hole), the employer must use a tagout system. Second, if the device can be locked out but the employer wants to use tagout instead, the employer must demonstrate that the tagout program provides an equivalent level of safety to lockout. That is a high bar.4Occupational Safety and Health Administration. 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout/Tagout)
To prove equivalence, the employer must add safety measures beyond the tag itself. OSHA lists examples: removing a circuit element, blocking a controlling switch, opening an extra disconnecting device, or removing a valve handle. The logic is that if you can’t lock the energy source off, you need extra layers that make accidental re-energization just as unlikely. Most facilities find it easier to retrofit lockable devices onto older equipment than to build a compliant tagout-only program. Employees working under tagout systems also need additional training on the limitations of tags, including the fact that tags can create a false sense of security.4Occupational Safety and Health Administration. 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout/Tagout)