Types of Lockout Tagout Devices: The Full LOTO Equipment List

I have spent twenty five years walking maintenance bays, and the LOTO failures I see almost never come down to a worker who did not care. They come down to hardware. The isolation point took a lock nobody had, so someone reached for a tag instead. Or the crew had padlocks and no hasp, so the second millwright just trusted the first one’s lock and started working.

So it is worth being precise about what a lockout tagout device actually is, because OSHA is precise about it. This page walks the full lock out tag out equipment list, what each device physically holds shut, and the four requirements every one of them has to meet under 29 CFR 1910.147. If you would rather have your crew watch it than read it, our lockout tagout training course covers the same ground.

Quick Answer: What Are the 4 Types of LOTO Devices?

OSHA 1910.147(b) defines only two: a lockout device and a tagout device. The “4 types of LOTO devices” on most exams means the four hardware families, which are padlocks, hasps, valve lockouts, and electrical or breaker lockouts. Everything else in a LOTO kit is a variation on those four.

What Is an Energy Isolating Device?

The term OSHA uses is energy isolating device, and 1910.147(b) defines it as a mechanical device that physically prevents the transmission or release of energy. The standard then names them: a manually operated electrical circuit breaker, a disconnect switch, a manually operated switch that disconnects all ungrounded supply conductors, a line valve, a block, and any similar device used to block or isolate energy.

Then it draws a line that catches people out. Push buttons, selector switches and other control circuit type devices are not energy isolating devices. A stop button tells the machine to stop. A disconnect switch stops the energy from getting there. Those are not the same thing, and a control that only signals cannot be locked out in any meaningful sense.

Here is the distinction that matters on the floor. The energy isolating device is the breaker, the valve, the disconnect. It is part of the machine. The lockout device is the padlock you hang on it. The isolating device does the isolating. The lock only holds it in the safe position so nobody can undo it while you are inside the guard. If you want the full definition and the yes-or-no test for what qualifies, we cover what energy isolation actually means separately.

When you see a tag on a machine or piece of equipment saying “Do Not Operate,” that is tagout. The tag indicates the machine is undergoing work, and it is only safe to use once the tag is removed by the person who put it there.

What Are the 7 Types of Hazardous Energy?

1910.147(b) defines an energy source as any source of electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or other energy. That is where the “seven types” comes from. Six are named and the seventh is the catch-all, which is deliberate, because gravity does not appear on that list and gravity has killed plenty of mechanics.

• Electrical. Line power, control power, capacitors, batteries, and anything still holding a charge after the disconnect is open.
• Mechanical. Rotating and reciprocating parts, flywheels, springs under compression or tension, belts and chains still under load.
• Hydraulic. Pressurised oil or water in cylinders, accumulators and lines. Accumulators are the ones people forget, because they hold pressure long after the pump is off.
• Pneumatic. Compressed air and gas in receivers, cylinders and lines.
• Chemical. Product in a vessel or line that can react, burn, or displace the air you are breathing.
• Thermal. Steam, hot surfaces, hot product, cryogenics. Cold counts.
• Other, which in practice means gravity. Elevated rams, blades, tailgates, suspended loads, anything held up by a system you are about to depressurise.

Every one of those needs a device that can hold it in a safe state, and that is what the table above sets out. Gravity is the one where the answer is usually not a padlock at all. It is a block or a pin.

The Full Lock Out Tag Out Equipment List

Here is the complete inventory, grouped the way a stocked LOTO station is actually laid out. If you are building a kit from scratch, this is the shopping list.

Locks and the things they attach to

• Lockout padlock, keyed different
• Lockout hasp, multi-hole
• Scissor or gang lock clamp
• Adjustable cable lockout
• Group lock box
• Portable lockout station or kit

Electrical

• Circuit breaker lockout, clamp-on and universal multi-pole
• Disconnect switch lockout
• Wall switch cover
• Plug and cord lockout enclosure
• Push button and E-stop cover, which is a guard against accidental contact and not an energy isolating device

Valves and lines

• Gate valve cover
• Ball valve clamp
• Butterfly valve lockout
• Plug valve lockout
• Blank flange or bolted slip blind
• Gas cylinder valve lockout
• Pneumatic and air line lockout

Mechanical and stored energy

• Safety block, ram prop and key block
• Adapter pin
• Wheel chock
• Steering wheel lockout
• Chain and wedge

Tags and documentation

• Tagout tag, non-reusable self-locking
• Lockout point identification label
• Machine-specific procedure placard

Two notes on that list. Push button covers are on it because every supplier sells them and your crew will find them in the kit, but they belong in the “keeps a hand off the button” category, not the isolation category. And the blank flange is the one people are surprised to see, because it does not look like safety equipment. 1910.147(b) names blank flanges and bolted slip blinds as lockout devices explicitly.

How Each Lockout Device Works

Lockout Padlock

These are the standard lockout devices for securing electrical systems. The workplace or facility should provide lockout padlocks, which must be distinct from other locks and identifiable with the user’s name.

The safety padlock must be able to stay locked and secured before you can remove the key. If you are using this type, they should not be keyed alike. You also should NOT let employees share these locks, because multiple people could open them, increasing the risk of an accidental re-energized source.

One more thing about padlocks that trips up new programs. Under 1910.147(c)(5)(ii)(B) your locks have to be standardised within the facility by at least one of colour, shape or size. Most plants pick colour. And they have to be the only devices used for controlling energy, so the padlock on the tool crib door cannot be the same padlock that goes on a breaker. Applying them is step four of the six steps of a lockout tagout procedure.

Valve Lock System

This type will physically prevent valve operation, ensuring that no one can accidentally or intentionally release dangerous chemicals during industrial repairs or maintenance. These come in several different varieties, including ball valves, butterfly valves, and gate valves. They are meant to stop the flow of material being controlled by the valve. A line valve is one of the devices 1910.147(b) names by hand, so there is no argument about whether a valve counts.

Circuit Breaker and Disconnect Switch Lockouts

This is the workhorse. A breaker lockout clamps over the toggle of a moulded case breaker and holds it in the off position with a hole for your padlock. They come in clamp-on styles that grip a single pole, universal styles that span multiple poles, and screw-mount styles for breakers with no lip to grab.

A disconnect switch lockout is usually simpler, because most industrial disconnects already have a hasp built into the handle. That matters legally, not just practically. 1910.147(b) says a device is capable of being locked out if it has a hasp or other means of attachment, or a locking mechanism built in. If it does, and it can be locked without dismantling or rebuilding it, then 1910.147(c)(2)(ii) says you lock it out. A tag is not your choice at that point.

For wall switches, a switch cover screws over the plate and encloses the toggle. I still find these missing in plants that lock out every breaker in the building perfectly, because a light switch does not feel like an energy isolating device. If it is what powers the thing you are working on, it is.

Adjustable Cable Lockouts

This type helps lock valves or panels that are difficult to reach. They are versatile and easy to install. Just loop and tighten the cable through the lockout points to secure a device. These are usually long adjustable cables and a lockout body with a built-in key lock.

Hasp

This device allows multiple workers to perform work on a single machine. Each worker can attach their lock and tag to the hasp, ensuring their safety. Hasps have multiple holes so each worker can attach their lock, indicating that they have locked it out. This shows that multiple employees have control over and are working on the device.

When a worker finishes, that worker removes their own lock. The machine stays locked out until the last lock comes off, and the last person off the job is the one who releases it.

Electrical Plug Lockout Device

There are different solutions to safely prevent someone from using a specific corded device. These are also called plug lockout devices or cord lockouts. These devices are designed to enclose or secure an electrical plug.

There is a wrinkle here worth knowing, because it saves arguments. 1910.147(a)(2)(iii)(A) says cord and plug connected equipment is outside the scope of the standard when the hazard is controlled by unplugging it and the plug stays under the exclusive control of the person doing the work. Exclusive control means in your pocket, in your hand, or in a box only you can open. The moment that plug is lying on the floor behind the machine where anyone could reach it, you are back inside the standard and you need a plug lockout.

Blocks, Pins and Chocks for Stored Energy

No padlock in the world holds up a raised dump bed. For stored gravity and mechanical energy, the device is physical: a safety block under the ram, a prop rod in a raised blade, a pin through a rotating assembly, a chock against a wheel.

1910.147(c)(5)(i) requires the employer to provide this hardware alongside the locks and tags, listing chains, wedges, key blocks and adapter pins by name. And 1910.147(d)(5)(i) requires that after the locks go on, all potentially hazardous stored or residual energy is relieved, disconnected, restrained, or otherwise rendered safe. Restrained is the word that means blocked.

The failure I have investigated more than once is a crew that locked out the hydraulics on a press perfectly and then worked under a platen held up by nothing but the oil they had just trapped. Bleed it down, or block it.

What Is a Tagout Device, and When Can You Use One?

A tagout device is a prominent warning device, a tag and a means of attaching it, fastened to an energy isolating device to indicate that it may not be operated until the tag is removed. That is 1910.147(b). Note what is missing from that definition: any physical restraint at all. This is the “Do Not Operate” tag you have seen hanging off a breaker handle.

The tag has to carry the identity of the person who applied it, per 1910.147(c)(5)(ii)(D), and 1910.147(c)(5)(iii) requires a legend warning against energising, with examples like Do Not Start, Do Not Open, Do Not Close, Do Not Energize and Do Not Operate.

The attachment has a hard specification most people have never read. Under 1910.147(c)(5)(ii)(C)(2), the means of attachment has to be non-reusable, attachable by hand, self-locking, non-releasable, with a minimum unlocking strength of no less than 50 pounds, and at least equivalent to a one-piece all-environment-tolerant nylon cable tie. A twist tie or a piece of string does not meet that.

Now the part that decides whether you are allowed to use one. 1910.147(c)(2)(i) says if the isolating device is not capable of being locked out, you use tagout. 1910.147(c)(2)(ii) says if it is capable of being locked out, you use lockout, unless you can demonstrate that a tagout system gives full employee protection as set out in 1910.147(c)(3). Demonstrating that is not a paperwork exercise. 1910.147(c)(3)(ii) expects additional measures such as removing an isolating circuit element, blocking a controlling switch, opening an extra disconnecting device, or taking the handle off a valve.

And since 2 January 1990, 1910.147(c)(2)(iii) has required that whenever equipment is replaced, majorly repaired, renovated, modified, or newly installed, the energy isolating devices be designed to accept a lockout device. So on any reasonably modern machine, tagout-only is a question you should rarely have to answer.

One last thing your crew has to be trained on, from 1910.147(c)(7)(ii): tags are essentially warning devices and give none of the physical restraint a lock gives, they must never be bypassed or ignored, they must be legible to everyone in the area, and, in OSHA’s own words, they may evoke a false sense of security.

How Does a Group Lock Box Work?

Lockboxes ensure it is safe to begin work in a group setting. After turning off the power source and using a LOTO procedure to keep it off, individuals must place the key to their lockout tagout devices in the lockbox. Then, they put their lockout padlocks on the box.

The facility picks its own colours. 1910.147(c)(5)(ii)(B) requires that locks be standardised by at least one of colour, shape or size, but it does not tell you which colour means what. If your plant uses orange for the operations lock and red for personal locks, that is your convention, not OSHA’s, and it needs to be written into your procedure so a contractor walking in can read it.

The rules that actually govern group lockout are in 1910.147(f)(3). Primary responsibility has to sit with one authorized employee for a defined set of workers, per (f)(3)(ii)(A). That person has to be able to determine the exposure status of every individual in the group, per (f)(3)(ii)(B). When more than one crew or trade is involved, one authorized employee gets overall control and coordinates between them, per (f)(3)(ii)(C). And under (f)(3)(ii)(D), each authorized employee affixes a personal lock to the group device, lock box or comparable mechanism when they begin work and removes it when they stop.

That last clause is the whole point of the box, and it is where I see programs drift. A lock box works because your lock on the lid means the isolation keys are unreachable. If someone signs in on a clipboard instead of hanging a lock, you do not have group lockout. You have a list.

What Must Every Lockout and Tagout Device Have?

1910.147(c)(5)(ii) says lockout and tagout devices shall be singularly identified, shall be the only devices used for controlling energy, shall not be used for other purposes, and shall meet four requirements. These four are worth memorising, because they are how a device gets judged.

• Durable. Capable of withstanding the environment for the maximum time it will be exposed, per (c)(5)(ii)(A)(1). Tags have to be printed so weather or wet locations will not make them illegible, per (A)(2), and must not deteriorate in corrosive areas where acids and alkalis are handled, per (A)(3).
• Standardized. Standardised within the facility by at least one of colour, shape or size, per (c)(5)(ii)(B). For tags, print and format have to be standardised too.
• Substantial. Locks have to resist removal without excessive force or unusual techniques such as bolt cutters, per (c)(5)(ii)(C)(1). Tags and their attachment have to resist inadvertent or accidental removal, with that 50 pound minimum unlocking strength, per (C)(2).
• Identifiable. The device has to indicate the identity of the employee who applied it, per (c)(5)(ii)(D).

The requirement people breach without noticing is “shall not be used for other purposes.” A safety padlock is not a locker lock, not a gate lock, and not the spare for the parts cage. The moment a lock has a second job, the identity it is supposed to communicate stops being reliable.

Documentation of Lockout Tagout Procedures

1910.147(c)(4)(i) requires that energy control procedures be developed, documented and used. 1910.147(c)(4)(ii) says the procedure has to spell out its scope, purpose, authorization, rules and techniques, and specifically has to include the steps for shutting down and isolating, the steps for placing, removing and transferring devices and who is responsible for them, and the requirements for testing to verify that the devices and controls actually worked.

There is an exception, and it is narrow. The note to 1910.147(c)(4)(i) lets you skip documenting the procedure for a particular machine only if all eight of these are true: no potential for stored or residual energy or reaccumulation that could endanger anyone; a single energy source that is readily identified and isolated; isolating and locking that source fully de-energises and deactivates the machine; the machine is isolated and locked out during the work; a single lockout device achieves the locked-out condition; that device is under the exclusive control of the authorized employee doing the work; the work creates no hazard for anyone else; and you have had no accidents involving unexpected activation during servicing.

Eight out of eight. In my experience the third and seventh knock most machines out. If you are not certain a machine qualifies, write the procedure. It takes an afternoon and it is the first thing a compliance officer asks for.

Alongside the procedures, keep the two certifications the standard requires: periodic inspection records under 1910.147(c)(6)(ii), identifying the machine, the date, the employees included and the person inspecting, and training records under 1910.147(c)(7)(iv), with each employee’s name and training dates.

Who Is Trained on Which Devices?

1910.147(c)(7)(i) splits training three ways, and the split is about devices as much as roles.

Authorized employees, under (c)(7)(i)(A), get training in recognising the hazardous energy sources that apply, the type and magnitude of energy present, and the methods and means necessary for energy isolation and control. In plain terms, these are the people who have to know which device goes on which isolation point and why.

Affected employees, under (c)(7)(i)(B), get instructed in the purpose and use of the energy control procedure. They do not apply devices. They need to recognise one and leave it alone.

Everyone else who works in an area where energy control procedures may be used, under (c)(7)(i)(C), gets instructed about the procedure and about the prohibition on trying to restart or re-energise anything locked or tagged out.

If you run a tagout system, everyone in the first two groups also gets the tag-limitation training in 1910.147(c)(7)(ii). And retraining is triggered, not scheduled, under 1910.147(c)(7)(iii)(A): a change in job assignment, a change in machines, equipment or processes that presents a new hazard, or a change in the energy control procedures.

California: Cal/OSHA Title 8 §3314

If you operate in California you are working to a second rule as well. Cal/OSHA Title 8 §3314, The Control of Hazardous Energy for the Cleaning, Repairing, Servicing, Setting-Up, and Adjusting Operations of Prime Movers, Machinery and Equipment, Including Lockout/Tagout, covers the same ground as 1910.147 but is not identical to it.

Two differences matter for devices. §3314 reaches setting-up and adjusting explicitly in its title and application, and it names unjamming as a covered activity. Federal 1910.147 gets to the same place through its definition of servicing and maintenance, but California says it out loud, and that removes an argument I have heard more than once about whether a quick adjustment counts.

The device requirements land in the same place. Your isolation point still needs hardware that can hold it in a safe state, and it still needs to be identifiable to the person who applied it. If you are a multi-state employer, build the kit to whichever rule is stricter for that isolation point and you will satisfy both.

Does 1910.147 Apply on a Construction Site?

No, and this catches people who move between general industry and construction. 1910.147(a)(1)(ii)(A) excludes construction and agriculture from the standard entirely. It also excludes shipyard, marine terminal and longshoring work under parts 1915, 1917 and 1918, electric utility generation, transmission and distribution installations, and oil and gas well drilling and servicing.

On a construction site the rule is 1926.417, Lockout and tagging of circuits, and it is far thinner. Three paragraphs: controls that are to be deactivated shall be tagged, de-energised equipment or circuits shall be rendered inoperative and have tags attached at all points where they can be energised, and tags shall plainly identify what is being worked on.

There is also 1910.333, which sets safe work practices including lockout and tagging for employees working on or near electric circuits and equipment. That is the standard that picks up the electrical exclusion in 1910.147(a)(1)(ii)(D).

The practical upshot on devices is this. A thinner standard is not permission for a thinner kit. If you send a crew from your plant to a construction project with the same lock box and the same breaker lockouts, you are fine and you are better protected than 1926.417 requires. If you send them with tags only because construction “only requires tags,” you have taken a step backwards for no reason.

Final Thoughts

OSHA puts a number on this. In its Lockout/Tagout fact sheet, DEP FS-3529, the agency estimates that compliance with the lockout tagout standard prevents roughly 120 fatalities and 50,000 injuries each year, and that workers injured by exposure to hazardous energy lose an average of 24 workdays recuperating.

Almost all of that comes down to whether the right device was on the right isolation point, applied by the person who was about to put their hands inside the machine. The hardware is cheap. A full station with padlocks, hasps, breaker and valve lockouts and a group box costs less than a single lost-time claim, and less than the citation that follows one.

Following lockout tagout guidelines keeps you compliant, and more to the point it keeps people whole when they are working around an electrical panel or an energised machine. For any of this to work, your people also need to know whether they are an authorized employee or an affected employee under the procedure, because that determines who is allowed to hang a lock at all.

If you need something to actually deliver this with, our Lockout Tagout PowerPoint covers it in a format you can run in a fifteen-minute toolbox talk, and there are free lockout tagout training videos if you want to see the devices in use first.

Frequently Asked Questions About Lockout Tagout Devices: