Cable Seals: Strength, Sizes, and Use Cases (With C-TPAT Tips)
In global shipping and logistics, cable security seals play a vital role in protecting cargo. They’re versatile, strong, and C-TPAT compliant when manufactured to ISO 17712 High-Security standards. But which size and strength do you need? Let’s break it down.
Why Cable Security Seals Matter
Cable seals are tamper-evident locking devices used to secure containers, trucks, tankers, and high-value cargo. Unlike fixed-length bolt seals, they offer flexibility: the steel cable can be adjusted to fit various locking points, making them useful in multiple applications.
For companies under C-TPAT (Customs-Trade Partnership Against Terrorism), using ISO 17712-compliant cable seals is a non-negotiable requirement to ensure supply chain security.
Strength Ratings of Cable Seals
Cable seals come in different diameters, which directly affect their breaking strength:
- 1.5mm – 3.5mm: Light-duty, suitable for small enclosures, drums, bags, and meter boxes.
- 3.5mm – 5mm: Medium-duty, often used for tankers, trucks, and warehouse doors.
- 5mm – 6mm+: Heavy-duty, required for international container shipping. These must meet ISO 17712 “H” High-Security classification.
For international container shipments, CBP requires cable seals of at least 5mm diameter to qualify as high-security under ISO 17712.
Common Sizes and Applications
The right seal size depends on your specific use case. Here are typical options:
| Cable Diameter | Breaking Strength | Applications |
|---|---|---|
| 2.5mm | ~650 kg | Utility meters, small access doors, airline carts |
| 3.5mm | ~1,150 kg | Tankers, trucks, warehouse cages |
| 5.0mm | ~1,500 kg | International shipping containers (C-TPAT/ISO 17712) |
| 6.0mm+ | ~2,000 kg+ | High-value cargo, heavy industry, customs-controlled shipments |
Use Cases of Cable Security Seals
- Shipping Containers: The most common application. Ensures compliance with C-TPAT and ISO 17712.
- Tankers: Prevents unauthorized access to fuel or chemical shipments.
- Trucking: Secures trailer doors during long-haul operations.
- Customs Transit: Provides visible tamper evidence for bonded cargo.
- Warehouses: Used on gates, cages, and restricted areas.
C-TPAT Compliance Tips for Cable Seal Users
- Always choose ISO 17712 “H” seals: Only high-security rated seals qualify under C-TPAT.
- Maintain a seal log: Record every serial number applied, checked, and removed.
- Train staff in VVTT inspection: Verify, View, Tug, Twist before accepting or breaking seals.
- Use unique serials: Ensure each seal has a laser-marked, non-duplicated ID.
- Replace compromised seals immediately: Never accept damaged or mismatched seals.
FAQs: Cable Seals and C-TPAT
Are all cable seals C-TPAT compliant?
No. Only ISO 17712-certified high-security cable seals with a diameter of at least 5mm are recognized as C-TPAT compliant.
Can cable seals be reused?
No. Cable seals are single-use tamper-evident devices. Once cut, they cannot be reapplied.
What’s the difference between cable seals and bolt seals?
Bolt seals are rigid and used primarily for containers. Cable seals offer flexibility for different locking points while still achieving ISO 17712 compliance at 5mm+ thickness.
Conclusion: The Right Cable Seal Protects Your Cargo
Cable security seals are a versatile, reliable, and C-TPAT-approved choice for securing cargo across industries. By selecting the right size and strength — and following CBP’s seal procedures — businesses can protect shipments and pass customs checks without stress.
Contact Acme Seals to source ISO 17712-compliant cable seals that meet C-TPAT requirements.