NLL Series Bolted Tension Clamp – Reliable Strain Hardware for Overhead Distribution Lines
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For overhead power distribution networks, stable dead-end anchoring of conductors is critical to grid safety. Among widely adopted power fittings, the NLL type bolted tension clamp (strain clamp) stands out as a cost-effective, easy-install solution for medium & low voltage overhead lines, favored by contractors, utility companies and power project suppliers worldwide.
What is NLL Tension Clamp?
NLL series is a bolt-type aluminum alloy strain clamp, also known as dead-end tension clamp. It is designed to fix and tension AAC, AAAC and ACSR conductors on terminal poles, angle poles and strain sections of overhead power lines up to 35kV. When working with insulated overhead conductors, an optional insulating cover can be equipped for extra insulation protection.
Different from compression-type strain clamps, NLL adopts U-bolt & pressure plate locking structure. No hydraulic crimping tools are required during field installation, which greatly cuts down construction time and labor cost on site. Common models cover NLL-1, NLL-2, NLL-3, NLL-4, matching different conductor diameters and tension load requirements.
Core Advantages of NLL Strain Clamp
✅ High-strength & anti-corrosion material Clamp body and keeper are cast from heat-treated high-strength aluminum alloy; U-bolts, nuts and pins are hot-dip galvanized steel / stainless steel. Excellent rust resistance for coastal, humid, desert and other harsh outdoor climates. Low magnetic hysteresis loss, helping reduce energy consumption during long-time operation.
✅ Strong & safe gripping performance Well-designed cambered wire groove distributes pressure evenly on conductor surface. The grip strength reaches over 95% of conductor rated breaking force, without crushing or damaging the outer strands of the cable. Stable electrical contact, low contact resistance and little heat generation under load.
✅ Tool-free quick installation & reusable Only standard spanners are needed for tightening bolts. Operators can finish mounting fast at height. It can be loosened, removed and reused when line reconstruction or maintenance is needed.
✅ Wide compatibility & flexible matching Fit for bare aluminum wire, ACSR steel-cored aluminum strand and overhead insulated aluminum conductor. It can assemble with tension insulators, clevises and socket eyes to form a complete strain assembly set for distribution projects.
Typical Application Scenarios
Urban & rural overhead distribution lines (10kV / 35kV)
Terminal & corner strain poles
Power station and substation outgoing lines
Rural electrification, solar farm grid connection
Power renovation & upgrade projects
Quality Standard
Our NLL tension clamps are manufactured in accordance with GB/T 2314, and meet IEC relevant power fitting standards. Each batch will go through mechanical failure load test, galvanizing thickness inspection and dimension check before delivery. Custom marking and packing are available upon customer request.
Final Words
When you are sourcing overhead line tension fittings with balanced reliability and budget, NLL bolted strain clamp is always a practical option. It minimizes construction difficulty while guaranteeing long-term running safety of distribution lines.
If you need datasheet, load curve or quotation for NLL series tension clamps, feel free to send us inquiry with your conductor specification and project voltage.
