A Comprehensive Guide to Circuit Breaker Lockout Devices: How to Choose the Right One for Your Safety Needs

The purpose of this guide is to describe what a circuit breaker lockout device is, what it does, what its benefits are and the different types of breaker lockout devices available on the market. In addition, this guide will cover how to select the right lockout device based on specific safety requirements, regulations, and environmental conditions.

Table of Contents

Understanding Lockout Devices

Types of Lockout Devices

Group Lockout Boxes

Tag Out Tags

Lockout Stations

Confined Space Covers

Choosing the Right Lockout Device

Best Practice for Using Lockout Devices

Understanding Lockout Devices

This section defines what lockout devices are and how they work to prevent electrical accidents.

What are lockout devices?

In the simplest terms, a lockout device is a safety device installed on a piece of equipment or machinery designed to prevent it from being switched on accidentally [1]. This could be anything from a padlock to a clamp that keeps the equipment or machinery from being turned on until needed. For circuit breakers, a lockout device will ensure it remains in the “off” position until it is determined that it is safe to switch it back on again [2]. A lockout device is vital when carrying out maintenance and repair work and prevents the risk of unexpected electricity re-energization from occurring. As such, understanding the purpose of lockout devices is crucial when it comes to ensuring safe electrical practices in the workplace.

Why are lockout devices necessary?

Having a lockout device installed on your circuit breaker is vital for workplace safety. It will greatly reduce the risk of any electrical accidents occurring and will ensure the well-being of everyone involved is protected, including yourself, your fellow workers, and anyone else in the area [3]. One of the most common workplace hazards when working on circuit breakers is the accidental release of energy during maintenance and repair work, causing serious injuries or even death. By installing a lockout device on the circuit breaker, you can effectively isolate it from other energy sources in the area and prevent such hazardous releases from occurring. This not only greatly reduces the risk of injury or fatalities, but also prevents serious damage to any equipment that could result in costly repairs or replacements [1].

How do lockout devices work?

All lockout devices serve the same purpose in keeping equipment turned off while maintenance work is carried out. However, the way this is achieved depends on the type of device used as well as the type of equipment it is installed on. Miniature circuit breakers often use pin-in and pin-out devices, which connect to the circuit breaker casing via small holes in the casing, or tie bar breaker devices which are secured under the breaker via a metal clip beneath the tie bar and between the poles. Other lockout devices for circuit breakers include clamp-on lockout devices that are secured over the circuit breaker switch via a secure metal clamp and universal breaker devices which use a clamp and padlock system [2].

Types of Lockout Devices

This section covers the different types of lockout devices available, including lockout tags, lockout hasps, and circuit breaker devices.

Lockout Padlocks

These are security padlocks used to lock LOTO devices in place [4]. While they can be keyed alike, this should be avoided for safety reasons. If this is unavoidable their distribution should be limited among employees [1].

Circuit Breaker/Electrical Lockouts

These lockout devices are designed to prevent power from being restored or re-energized while equipment is being serviced. Once the power is shut off, the electrical lockout device fits over the switch and is often held in place by a padlock [4].

      View Circuit Breaker Lockouts

Valve Lockouts

This type of lockout device isolates energy in pipes by preventing valves from being opened which could affect any pipes or equipment that are being worked on downstream. The device is fixed over the closed valve and held in place by a padlock [4].

KIT-1457VE410KA-Valve-Electrical-Lockout-Kit     View Valve Lockout Kits

Cable Lockouts

For harder-to-lock devices such as handles and gate valves, cable lockouts provide safety and security during maintenance and repairs. The cable passes through the handles or valves and is pulled tight, then locked in place using a padlock [4].

    Total Lockout image    View Cable Lockout Devices

Steering Wheel Lockouts

These devices attach to the steering wheel of a vehicle that is being maintained and repaired. They generally do not disable the steering wheel but rather display a warning not to use the vehicle while it is being worked on [4].

Flange Lockouts

These cover the bolts on pipeline flanges to prevent them from being opened while the pipeline is being worked on. A padlock holds the flange lockout in place to prevent it from being accidentally removed [4].

Total Lockout Master Lock Blind Flange Lockout image    View Flange Lockouts

Gas Cylinder Lockouts

This type of lockout device covers valve handles and handwheels to prevent access to the main tank while work is ongoing. They are held in place with a padlock to protect them from any unauthorized access [4].

    VLO-S3910-Gas-Valve-Lockout    View Gas Cylinder Lockouts

Pneumatic Lockouts

These lockout devices secure pneumatic fittings and regulators in place to prevent equipment from being energized. They are held in place by a padlock to ensure the pneumatic fittings do not connect to any pressurized air sources [4].

VLO-BAN-Q01-Pneumatic-LockoutGlad Lock, trailer glad hand air line lock to lockout a trailer to prevent drive-off.    View Pneumatic Lockouts

Lockout Hasps

Lockout hasps allow multiple workers to service the same equipment at one time. The hasp is applied to a lockout and has multiple shackle holes to allow other lockout devices to be attached. Once all lockout devices are removed the equipment can become operational again [4].

HAS-ALO80-American-Lock-Hasp    Master Lock 1" Nylon safety Lockout Hasp Padlock, red.    View Lockout Hasps

Group Lockout Boxes

These boxes are used to hold the keys used to lock padlocks in place that secure lockout devices during servicing. This provides a control point where each worker can select a padlock and key needed for maintenance or repair work [4].

STO-TYPE1-GROUP-LOCKOUT-BOX        View Group Lockout Boxes

Tagout Tags

When a lockout device is in use, these tags are used to alert workers that equipment is out of service. They are placed over the shackle of the padlock and are part of the OSHA standard for the Control of Hazardous Energy (Lockout/Tagout) [4].

SIG-TAR404-TAR472-Do-Not-Operate-Tags    SIG-TAR132-TAR154-Unsafe-Do-Not-Use-Roll-Of-Tags    View Lockout Tags

Lockout Stations and Kits

Lockout stations allow you to store multiple lockout devices in one location for easy access. Stations are often wall-mounted or sit on the counter, while kits allow you to transport multiple devices to any location [4].

STO-1483BP1106-Lockout-Station        View Lockout Stations

Confined Space Covers

For confined areas, confined space covers prevent access from unauthorized personnel while work remains in progress. They also offer protection from the elements and pests during ongoing work [4].

Choosing the Right Lockout Device

This section covers the factors that influence the selection of the right lockout device, such as the type of circuit breaker, voltage, and environment.

Choosing based on Circuit Breaker Type

Not all lockout devices will fit the same type of circuit breaker, and it is important to know which device will fit the specific circuit breaker you intend to work on. One way to determine which lockout device will fit your breaker is to measure the breaker toggle. By measuring the width, length, and thickness of the toggle you can work out which device is needed [5]. For example, BAB breaker locks, BR breaker locks, GE breaker locks and Square D breaker locks work well with clamp-on devices, in particular the Square D FH breaker range. Universal breaker lock-out devices are good for multi-pole devices [6].

Choosing Based on Voltage

Another way to determine what lockout device to use is by looking at the voltage of the circuit breaker. Circuit breakers can range from 120V to 600V, and there are devices that can work with each voltage range. For example, oversized lockout devices are designed to work with voltages of 480V and 600V, while snap-on devices work well with 120V [6].

Choosing Based on Environment

Every circuit breaker switch exists in its own environment and a different lockout device setup is required to be used on it. Some require Snap-On or clamp-on devices or are designed for oversized devices. Miniature circuit breaker lockouts also have their own standards such as pin-ins, pinouts, and tie-bars [6].

Best Practices for Using Lockout Devices

This section provides tips for the proper use, installation, and maintenance of lockout devices to ensure optimal safety.

Safety Tips for Lockout Tag Usage

To reduce the harmful effects of hazardous energy while working on equipment and machinery, you should employ the following safety tips [7]:

  • Read through the OSHA standard for The Control of Hazardous Energy (Lockout/Tagout) (29 CFR 1910.147) to understand your responsibilities in protecting workers from hazardous energy. Make sure to keep a copy on hand for future reference.
  • Create a lockout/tagout (LOTO) procedure for all workers performing maintenance and repair work. The procedures should be based on OSHA standard 1910.147 and outline what actions workers should take when working with equipment, using, and removing lockout devices, and looking after fellow workers.
  • All workers involved in the maintenance and repair of electrical equipment should be fully trained in LOTO procedures and the correct usage of lockout devices. This also includes any workers in the area who need to be aware of safety procedures while lockout procedures are in effect.


[1] https://safetyculture.com/topics/lockout-tagout/

[2] https://trdsf.com/blogs/news/circuit-breaker-lockout-installation

[3] https://www.newstricky.com/the-importance-of-circuit-breaker-lockout-ensuring-electrical-safety/

[4] https://www.grainger.com/know-how/equipment-information/kh-guide-to-choosing-lockout-tagout-devices

[5] https://totallockoutusa.com/2020/08/21/which-lockout-device-will-fit-my-breaker/

[6] https://d37iyw84027v1q.cloudfront.net/Common/Circuit_Breaker_Lockout_Reference_Guide.pdf

[7] https://www.osha.gov/control-hazardous-energy


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