Master Lock Zenex Composite Safety Padlocks

Master Lock Zenex Composite Safety Padlocks

Master Lock Zenex composite safety padlocks are designed specifically for Lockout Tagout (LOTO) applications. Their lightweight thermoplastic composite bodies make them well suited to personal energy isolation during maintenance, servicing, cleaning and inspection work where hazardous energy must be safely controlled.

The Zenex range includes several safety padlock configurations. Important differences include the shackle material and dimensions, keying system and colour. This allows the padlock to be selected according to the isolation point, working environment and Lockout Tagout procedure used within your organisation.

What is Zenex composite?

Zenex is the thermoplastic composite material used by Master Lock for the bodies of several Lockout Tagout safety padlock ranges. It provides a durable, lightweight lock body designed for industrial use. Depending on the series, the Zenex body can be combined with a hardened-steel, nylon or stainless-steel shackle.

The Zenex lock body itself is electrically non-conductive. It is important, however, to distinguish between the lock body and the complete safety padlock. A Zenex padlock fitted with a metal shackle should not automatically be described as fully non-conductive. For applications where electrical conductivity is an important selection criterion, Master Lock offers models such as the dielectric 406 series with a nylon shackle.

Which Master Lock Zenex series should I choose?

The best Zenex safety padlock depends primarily on the application, required shackle material and the size of the opening in the lockout device. Important Zenex ranges include the Master Lock 410, 406 and S31 series.

Steel, nylon or stainless-steel shackle?

Metal shackle – Master Lock 410

The Master Lock 410 series combines a Zenex composite lock body with a 6 mm metal shackle. It is a widely used option for general industrial Lockout Tagout applications and is available in different colours, shackle lengths and keying configurations.

Because the 410 series uses a metal shackle, the complete padlock should not automatically be considered fully non-conductive or non-sparking. Where electrical conductivity or potential spark generation is an important selection criterion, always check the properties of the specific padlock configuration.

Nylon shackle – Master Lock 406

The Master Lock 406 series is a dielectric Zenex safety padlock with a 6 mm nylon shackle. According to Master Lock, the plastic shackle helps prevent electrical current from passing from the shackle to the key and helps protect against electrocution and arc flashing.

Master Lock also specifies that all components of the 406 series are non-sparking and non-magnetic. This makes the 406 particularly relevant for Lockout Tagout applications where electrical conductivity is an important consideration.

For additional polymer-bodied options, view our nylon safety padlocks.

Stainless-steel shackle – Master Lock S31

The Master Lock S31 series combines a Zenex composite body with a 4.76 mm marine-grade 316 stainless-steel shackle. The thinner shackle can be useful where the locking point has a smaller opening, while the stainless-steel construction provides enhanced corrosion resistance.

Master Lock specifically positions the S31 for demanding and corrosive environments. The lock body is also designed to withstand chemicals and temperature extremes and is UV stable.

Which shackle size should I choose?

Always check that both the shackle diameter and the available shackle clearance are suitable for the lockout device before ordering. A thinner shackle may be required for small locking openings, while a longer shackle can provide additional clearance where the isolation point is difficult to access.

Depending on the Zenex series and configuration, different shackle diameters and shackle heights are available. Use the filters on this page to select safety padlocks by shackle material, shackle diameter and shackle height.

Keyed Different, Keyed Alike or Master Keyed?

The keying system is another important consideration when selecting a Zenex Lockout Tagout safety padlock. Depending on the series and configuration, Master Lock offers several keying options:

• Keyed Different (KD): each padlock has its own individual operating key. This is the most common configuration for personal LOTO padlocks.
• Keyed Alike (KA): multiple padlocks within a defined group can be operated using the same key.
• Keyed Different + Master Keyed (KD + MK): each padlock retains its own individual key, while an authorised master key can open multiple padlocks within the defined system.
• Keyed Alike + Master Keyed (KA + MK): a defined group of padlocks shares the same operating key while also forming part of a controlled master-key system.

Keyed Different is commonly selected for personal Lockout Tagout padlocks because each authorised employee can retain control of their own lock and key. Keyed Alike and Master Keyed configurations can be useful for specific applications or organisational structures, but the chosen system should always support the organisation's Lockout Tagout procedure and key-control requirements.

For a more detailed explanation of the available keying configurations and larger key-management systems, see our Lockout Tagout keying systems page.

Colour coding and identification

Zenex safety padlocks are available in a variety of colours. Organisations can use these colours to create their own visual identification system, for example by employee group, department, trade, location or application.

There is no single universal colour code that applies to every Lockout Tagout programme. The meaning assigned to each colour should therefore be clearly defined and consistently applied within the organisation's own LOTO procedure.

Selected Master Lock Zenex safety padlocks can also be permanently identified using laser engraving or identification labels. Depending on the chosen configuration, this can be used to add an employee name, department, identification number or other relevant information.

How to select a Zenex safety padlock

When selecting a Master Lock Zenex safety padlock, consider the following:

• shackle material: metal, nylon or stainless steel;
• shackle diameter and shackle height;
• required electrical characteristics;
• environmental conditions at the isolation point;
• required keying system: KD, KA and, where appropriate, Master Keyed;
• required colour and identification options;
• the requirements of your organisation's Lockout Tagout procedure.

If you require a different lock-body material, you can also view our aluminium safety padlocks.

Not sure which Zenex configuration is suitable for your application? Our technical specialists can help you select the appropriate safety padlock and advise on suitable keying configurations.

Frequently asked questions about Zenex safety padlocks

What is a Zenex safety padlock?

A Zenex safety padlock is a Master Lock Lockout Tagout padlock with a lightweight thermoplastic composite body. Depending on the series, the body is combined with a metal, nylon or stainless-steel shackle.

What is the difference between the Master Lock 410 and 406?

Both series use a Zenex composite lock body. The main difference is the shackle. The Master Lock 410 uses a 6 mm metal shackle, whereas the Master Lock 406 uses a 6 mm nylon shackle and is specifically designed as a dielectric safety padlock for applications where low electrical conductivity is important.

Are all Zenex safety padlocks non-conductive?

No. The Zenex lock body is non-conductive, but some Zenex safety padlocks use metal shackles. If low electrical conductivity of the complete padlock is required, the shackle and other components must also be considered. The Master Lock 406 series is specifically designed as a dielectric configuration.

Are Zenex safety padlocks non-sparking?

Not every Zenex padlock should automatically be considered non-sparking. Master Lock specifically states that all components of the 406 series are non-sparking and non-magnetic. Other Zenex series use different components, including metal shackles. Always check the properties of the specific model when potential spark generation is an important selection criterion.

Are Master Lock Zenex safety padlocks ATEX certified?

Master Lock states that the components of the 406 series are non-sparking and non-magnetic. This is not the same as ATEX certification. We therefore do not make a general ATEX certification claim for the Zenex range on this page. If ATEX certification is required for your application, always verify the current certification of the specific product before selection.

What keying options are available for Zenex safety padlocks?

Depending on the model, Zenex safety padlocks are available as Keyed Different (KD), Keyed Alike (KA) and in Master Keyed configurations. The appropriate keying system depends on your organisation's Lockout Tagout procedure and key-control requirements. More information is available on our Lockout Tagout keying systems page.

Which colour Zenex safety padlock should I use?

There is no universal colour requirement for all Lockout Tagout applications. Colours can be used for visual identification by employee, department, trade, location or application. The chosen colour system should be clearly defined in the organisation's Lockout Tagout procedure.

View our complete range of Lockout Tagout safety padlocks for additional Master Lock, Brady and ABUS options.