Which Lockout-Tagout Padlock Do I Need?

Choosing the right Lockout-Tagout padlock involves more than just selecting a colour or brand. The padlock must fit the isolation point, be suitable for the working environment and support the key-control and identification requirements of your organisation's Lockout-Tagout procedure.

Depending on the application, you may need to choose between different body materials, shackle materials, shackle dimensions and keying systems such as Keyed Different, Keyed Alike or Master Keyed.

This guide explains the different LOTO safety padlock types and helps you select the right padlock for your application.

Quick LOTO Padlock Selection Guide

Start with the application rather than the brand or colour. The following decision path covers the most important choices.

Which LOTO Padlock Fits Your Application?

Important: always check the specifications of the complete padlock. A plastic, nylon, thermoplastic or insulated body does not automatically mean that the shackle is non-conductive.

1. Start with the Isolation Point

Before comparing materials or brands, determine the isolation point.

A LOTO padlock can be applied directly to an energy-isolating device, or used to secure a compatible lockout device that prevents the isolation point from being returned to its normal operating position.

Typical applications include:

- circuit breakers and electrical switches;
- disconnect switches;
- valve lockout devices;
- plug and connector lockouts;
- pneumatic lockout devices;
- lockout hasps;
- compatible machine and equipment isolation points.

2. Which LOTO Padlock Material Should I Choose?

There is no single padlock material that is best for every Lockout-Tagout application. When comparing different LOTO padlock types, always consider the lock body and shackle separately.

Thermoplastic or Composite LOTO Padlocks

Thermoplastic safety padlocks, such as the Master Lock Zenex™ range, provide a lightweight alternative to metal-bodied LOTO padlocks.

Depending on the specific product range, thermoplastic or composite lock bodies can offer resistance to chemicals, corrosion, UV exposure and extreme temperatures. Always check the specifications of the individual padlock range for the environment in which it will be used.

A non-conductive thermoplastic body does not necessarily make the complete padlock non-conductive. The Master Lock 410 series, for example, uses a Zenex™ thermoplastic body but standard 410 models have a metal shackle.

Consider a thermoplastic or composite LOTO padlock when:

- you want a lightweight alternative to a metal-bodied LOTO padlock;
- resistance to chemicals, corrosion, UV exposure or temperature extremes is required and supported by the selected model;
- you require a non-conductive lock body.

View our thermoplastic/composite LOTO padlocks.

Nylon LOTO Padlocks

Nylon-bodied safety padlocks are another lightweight option widely used for Lockout Tagout.

A nylon lock body can be useful where low weight and a non-conductive body material are important. However, the electrical properties of the complete padlock depend on more than the body material alone.

The shackle material must therefore be checked separately. Depending on the product range, nylon-bodied padlocks can be supplied with metal, cable or non-conductive nylon/plastic shackles.

Consider a nylon LOTO padlock when:

- you require a lightweight LOTO padlock;
- a non-conductive lock body is required;
- you need to select the shackle material separately according to the application.

View our nylon LOTO padlocks.

Aluminium LOTO Padlocks

Aluminium LOTO padlocks provide a lightweight metal-body alternative.

Depending on the manufacturer and product range, aluminium padlocks can be supplied with steel, coated steel, stainless-steel or non-conductive plastic shackles. Some aluminium LOTO padlocks also have an insulating or protective plastic coating around the lock body.

The aluminium body remains a metal component. A plastic coating around the body should therefore not automatically be interpreted as meaning that the complete padlock is non-conductive.

Consider an aluminium LOTO padlock when:

- you want a lightweight metal-bodied LOTO padlock;
- you require a metal body with less weight than a laminated-steel padlock;
- you need a choice of different shackle materials;
- the environmental properties of the selected aluminium padlock suit the application.

View our aluminium LOTO padlocks and composite-covered aluminium LOTO padlocks.

Laminated-Steel LOTO Padlocks

Laminated-steel safety padlocks provide a robust metal construction for industrial Lockout Tagout applications.

They are generally heavier than thermoplastic, nylon or aluminium alternatives and contain conductive metal components. Laminated steel can therefore be a suitable choice where mechanical robustness is important and electrical conductivity is not a limiting factor.

Consider a laminated-steel LOTO padlock when:

- you require a robust metal-bodied padlock;
- mechanical strength is an important consideration;
- electrical conductivity is not a limiting factor;
- the additional weight of a steel padlock is acceptable for the application.

View our laminated-steel LOTO padlocks.

If you are still comparing materials, view our full range of LOTO safety padlocks to compare thermoplastic, nylon, aluminium and laminated-steel options.

3. Do I Need a Non-Conductive LOTO Padlock?

This is particularly important for electrical Lockout-Tagout applications.

Terms such as plastic, nylon, thermoplastic, insulated and non-conductive should not be treated as interchangeable.

A LOTO padlock may have:

- a non-conductive thermoplastic body with a steel shackle;
- an aluminium body with an insulating plastic coating;
- a coated steel shackle;
- a stainless-steel shackle;
- a purpose-designed non-conductive nylon or plastic shackle.

These configurations do not have the same electrical properties.

If your application requires a non-conductive shackle, choose a padlock specifically designed with a nylon or plastic shackle. Do not assume that a plastic body or insulating coating makes the complete padlock non-conductive.

4. Which Shackle Size Do I Need?

Once you have selected the appropriate body and shackle materials, check whether the padlock will physically fit the isolation point.

Two dimensions are particularly important:

- Shackle diameter – determines whether the shackle can pass through the designated locking point.
- Shackle clearance – determines how much usable space is available between the lock body and the inside of the shackle.

Many LOTO padlocks are available with a shackle clearance of approximately 38 mm. Selected product ranges also offer longer shackles with approximately 75–76 mm clearance.

A longer shackle can provide additional reach where the isolation point is recessed or difficult to access. However, longer is not automatically better. Choose the shortest shackle that provides sufficient clearance for the application.

Where a conventional padlock shackle cannot easily fit the isolation point, a flexible cable padlock may be more suitable.

5. Keyed Different vs Keyed Alike for LOTO

After selecting the physical padlock, determine how the keys should be organised. The three terms you will encounter most often are Keyed Different (KD), Keyed Alike (KA) and Master Keyed (MK).

Keyed Different (KD)

With Keyed Different, each padlock has its own individual operating key.

This is commonly used for personal Lockout Tagout. Each authorised employee can apply their own personal padlock and retain control of the corresponding key.

Keyed Alike (KA)

With Keyed Alike, multiple padlocks within a defined group can be operated using the same key.

KA can be useful where one authorised person needs to control several padlocks, for example when several isolation points need to be secured as part of the same task.

Keyed Alike should not be used to bypass individual control where multiple employees are each required to apply and control their own personal LOTO padlock.

Master Keyed (MK)

A Master Key system adds an additional controlled key level. Depending on the manufacturer and system, Master Keying can be combined with Keyed Different or Keyed Alike groups.

A Master Key should not be treated as a convenient way to bypass personal Lockout Tagout. Access to master keys, how they are stored and the circumstances in which they may be used should be clearly defined within the organisation's LOTO and key-management procedures.

For larger installations, plan the key structure before ordering the padlocks. This makes it easier to manage individual employees, departments, duplicate key codes and future expansion.

Learn more about Lockout Tagout keying systems →

6. The meaning of different colours for LOTO padlocks?

Different padlock colours can support visual identification within a Lockout-Tagout procedure.

For example, colours may be used to distinguish between:

- departments;
- maintenance teams;
- employees and contractors;
- sites or production areas;
- specific functions or applications.

There is no universal LOTO colour code that gives every padlock colour the same meaning in every organisation.

If colour coding is used, the meaning of each colour should be clearly defined in the organisation's Lockout Tagout procedure and communicated to the relevant personnel.

Colour coding can support identification, but it should not replace individual identification of the padlock and authorised user.

7. Should a LOTO Padlock Be Key-Retaining?

A key-retaining padlock only allows the key to be removed when the padlock is locked.

This can be useful for a personal Lockout-Tagout procedure because the operating key remains with the padlock while it is open and is only released once the padlock has been secured.

Many dedicated LOTO padlock ranges use a key-retaining design. However, this is not universal, so check the specifications of the individual model if this feature is required by your procedure.

Common mistakes when selecting a LOTO Padlock

Using a normal padlock instead of a LOTO safety padlock for Lockout-Tagout purposes

A personal LOTO padlock should be dedicated to hazardous-energy control and should not also be used for lockers, gates, toolboxes or other general safety purposes.

Assuming a plastic padlock is always non-conductive

Always check the shackle material. A thermoplastic or nylon body can still be combined with a conductive steel or aluminium shackle.

Choosing the key system after ordering the padlocks

For larger quantities, determine your KD, KA and Master Key requirements before ordering. A planned key structure is easier to manage and expand later.

Automatically choosing the longest available shackle

A longer shackle is useful when additional clearance is required, but it should not be selected simply because it offers more space. Match the shackle dimensions to the actual isolation point.

Using different coloured padlocks as the only form of identification

Colour coding can make a LOTO system easier to recognise, but the organisation should also define how individual padlocks and authorised employees are identified.

LOTO Padlock Selection Checklist
Before ordering a Lockout Tagout padlock, use the following checklist:

- What energy-isolating device or LOTO device will the padlock secure?
- Which lock-body material is appropriate for the application?
- Which shackle material is required?
- What shackle diameter will fit the locking point?
- How much shackle clearance is required?
- Is a standard shackle, longer shackle or flexible cable required?
- Does electrical conductivity need to be considered?
- Are corrosion, chemicals, UV exposure or temperature important for the application?
- Do you need Keyed Different, Keyed Alike or a Master Key system?
- How will personal padlocks and their users be identified?
- Does the organisation use a defined LOTO colour-coding system?
- How will the key system be managed and expanded in the future?

These questions will usually narrow the choice down to a small number of suitable padlocks.

Do you need help choosing the right safety padlock for your application?

Lockout-Tagout-Shop supplies Lockout Tagout padlocks from ABUS, Master Lock and Brady in different body materials, shackle materials, shackle sizes, colours and keying systems.

Whether you need padlocks for personal LOTO, electrical isolation, a large managed key system or an unusual isolation point, we can help you select a configuration that matches your application and LOTO procedure.

View all Lockout Tagout safety padlocks →