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In this article we explore the ‘flexibility of the flexiGrip’ – giving you an in-depth look into our range of metal cable seals used across the world, the benefits of using cable seals for your security, and the wide range of customisation options available to you.

Cable security seals play a crucial role in the transportation process by providing protection and helping to prevent theft, a major concern in the logistics industry.

What are Cable Seals?

Cable security seals (also known as 'cable seals’ or wire rope seals), are flexible, strong types of tamper evident seals popular across many industries, most notably in the freight, transport and logistics industry, but also food / pharmaceutical and manufacturing sectors. They help to reduce theft by posing a physical and psychological barrier to entry, as well as providing clear evidence of tampering should any attempt be made to open cargo enclosures fraudulently.

Cable security seals generally consist of a metal or plastic body, with the cable/wire rope permanently cinched or clamped at one side of the body, with a one-way tamper-evident locking chamber at the other end of the body. The wire rope is inserted into the locking mechanism and gradually tightened to suit the application. The locking mechanism is designed to ensure the cable is securely locked in place, maintaining the safety and integrity of the sealed item. The cable is produced using 'non-preformed' cable which frays when cut open, making re-insertion impossible and providing clear evidence of seal tampering upon visual inspection.

In short, cable security seals provide a strong barrier against fraudulent cargo access, visible indication of tampering, and are used across industries to ensure that containers remain sealed and protected from theft, collusion or fraud.

Why use Cable Seals?

The most common commercial uses of cable security seals include securing shipping containers, rail cars, and trucks. These tamper evident seals play a critical role in protecting high value goods during transit by maintaining product integrity.

One of the key benefits of using cable seals is the combination of the strength and flexibility of the wire cable construction. Cable security seals can be tailored in terms of their strength and length so that they are effective for many applications: from a small drum, crate or cage all the way through to sealing of a 40ft sea cargo container.

Cable Thickness

Cable seals, from lightweight 1.5mm diameter to heavyduty 5mm cable diameter 

Thinner diameters (<2.5mm cables) are pliable and suited best to small-scale applications, whereas heavier gauge 3, 4 and 5mm cables are much stronger, and can securely seal large-scale applications.

The choice of cable thickness directly impacts the seal's strength and suitability for different security needs. Thinner cables offer ease of use and flexibility, making them perfect for securing items like bags, crates, or smaller containers where high tensile strength is not as critical. Conversely, thicker cables provide enhanced resistance to cutting and tampering, serving as a visual indicator of security making them the preferred option for securing shipping containers, railway cars, and other high-value or heavy-duty assets.

Overall, selecting the appropriate cable thickness and seal configuration is a fundamental security measure that helps prevent theft, maintain the integrity of shipments, and comply with industry regulations. Proper use of cable security seals (combined with regular visual checks) forms an effective barrier against unauthorised access in the logistics industry and beyond.

Cable Security Seals versus Plastic Seals & Cable Ties

Cable seals have significantly higher pulling strengths compared to plastic pull-through seals, which are sometimes used as alternatives. While some of the strongest plastic pull-through seals can withstand pulling loads of up to 50KgF, even our lightest cable security seals are twice as strong. Our most robust barrier cable seals, such as the 325M and 500M models, are over 20 to 50 times stronger than plastic seals! They are also more durable solutions over longer periods of use, as they will not accidentally break in use. Special tools (such as bolt croppers) are required to open these types of seals, so opening the seal is always an intentional decision.

Plastic seals, on the other hand, are designed to be easily broken or cut open with light tools, making them less secure. An even worse solution is a cable tie, which are not suitable for tamper-evident applications because they can be easily undone and re-tied, unlike tamper-evident seal models.

Cable Seal Classification: Security vs. High Security Seals

Another benefit of cable seals over other types of seals are the ISO standards that our range of cable seals are certified to. Security seals are designed to meet international standards such as ISO17712, providing a strong physical barrier against unauthorised access.

The Flexigrip 150M cable seal is certified by the Security Seal Testing Authority (SSTA) as an accepted HMRC customs seal, and for international shipping containers sent by sea freight. Our Flexigrip 325M and Flexigrip 500M seals are ISO17712 ‘H’ High Security Classification and C-TPAT compliant, meaning they are suitable for US customs entry.

High security classification seals are used on cargo containers and rail cars to ensure compliance with international shipping regulations, serving as a barrier and deterrent to unauthorised access. Regular visual checks of seals is important to verify their integrity and compliance with security protocols. There are different seal types, and choosing the right type of seal is essential for meeting security and regulatory requirements. These certifications make cable seals more suited to customs movements.

Industry Applications of Cable Seals

Cable security seals are used across various industries to provide tamper-evident security and protect valuable assets. Key applications include:

• Transport and Logistics Industry: Securing shipping containers, trucks, trailers, and rail cars to prevent theft and unauthorised access.

• Food and Pharmaceutical: Protecting shipments to maintain product safety and regulatory compliance.

• Utility and Energy: Securing access panels, valves, and meters in outdoor and industrial environments.

• Industrial and Manufacturing: Safeguarding machinery, equipment, and storage containers.

• Retail and Wholesale: Protecting high-value inventory with traceable, color-coded seals.

• Government and Military: Securing sensitive equipment and classified materials with top-security, tamper evident seals.

You can also view our guide to the Top 10 Applications for Cable seals here.

Our Range of Cable Security Seals

flexiGrip cable security seals are available in many configurations, including metal or plastic bodies, and in cable diameters from 1.5mm up to 5mm. Each cable seal can be customised with unique serial numbers, permanently laser-etched for traceability and chain-of-custody verification. These seals are constructed from high-quality materials, including options for plastic security seals, to ensure durability and tamper resistance. Choosing the right security seal protects your assets and ensures compliance with security protocols.

Barrier seals incorporate tampering indicators that clearly show if unauthorised access or tampering has occurred, providing both a physical and visual deterrent. Below chart provides an overview of our range:-...

We have put together the Top 10 Use Cases for Cable Security Seals, and explain in each case why cable seals are particularly suited for these types of applications.

Cable security seals are flexible and strong types of security seals popular across all types of industries, including freight and transport, food & pharmaceutical, industrial and manufacturing and other sectors. We have put together the below Top 10 Use Cases for Cable Security Seals, and explain in each case why cable seals are particularly suited for these types of applications.

Top 10 Use Cases for Metal Security Seals

Use Cases of Cable Security Seals	Illustration
Road Haulage / Trailer Security Cable seals are often used to lock through the locking hasps of road trailer doors, as a stronger solution and more tamper-evident solution than easier breaking pull-through or fixed length trailer seals which can be used alternatively. Our flexiGrip 150M seal is a HMRC Customs accepted seal, and road freight transiting the UK-EU customs borders can utilise customs-accepted cable seals as a cost-effective security seal solution for cross-border road shipments.
Shipping Containers ISO17712 High Security Cable seals are strong barrier seals suitable for sealing of shipping containers transiting customs borders. Cable Seals are sometimes preferred to more conventional bolt seals for shipping containers to provide increased security, particularly for high value shipments involved in food/drink and pharmaceutical logistics:         i.            Extra-long cable seals can seal around the vertical locking bars, which can provide superior security compared to sealing at locking hasps        ii.            Our specialised double-locking Flexigrip 500MD is a heavy-duty cable seal which provides a double locking mechanism, for increased security shipments.
Air Cargo Containers Air cargo containers are often subject to vibration, knocks and shocks during air transport and ground movements, and as such lower-strength plastic pull-through seals are not often strong enough to provide effective tamper-evident security. Cable seals provide higher strength security to ensure that seals do not open whilst in transit, providing a full chain of custody of sealed air cargo enclosures from point-to-point.
Rail Cars Cable seals are ideal for sealing individual rail freight car doors. Our range of cable security seals have rugged design features to ensure chain of custody during rail...