Bolted NLD Malleable Iron Strain Clamp

A: Key installation points include: 1) Conductor preparation: Strip 80–120 mm of the insulation layer, then use sandpaper or a wire brush to remove any oxide layers or grease; 2) Bolt pre-tightening: Pre-tighten the bolts in a diagonal cross sequence (e.g., 1→3→2→4) to a torque of 5–10 N·m; 3) Torque tightening: Use a calibrated torque wrench; apply a torque of 25–30 N·m for 16–50 mm² conductors, and 35–40 N·m for 70–240 mm² conductors; 4) Post-installation inspection: Verify the tightness of the bolts and the contact fit between the conductor and the clamp (ensuring no gaps), and conduct a tension test.

A: The main advantages include: 1) Bolt-type fastening design: No specialized crimping tools are required; installation can be performed using a standard wrench; 2) Reusability: Can be repeatedly dismantled, facilitating maintenance and conductor replacement; 3) High-strength aluminum alloy material: Lightweight construction reduces the structural load on utility poles and towers; 4) Anti-slip serrated design: Increases friction to prevent conductor slippage; 5) Surface anti-corrosion treatment (electrophoretic coating or hot-dip galvanizing): Suitable for use in harsh outdoor environments; 6) Compliance: Meets the international standard IEC 61284.

A: The NLD series typically refers to bolt-type tension clamps made of malleable cast iron, whereas the NLL series refers to bolt-type tension clamps made of aluminum alloy. The NLL series is lighter in weight and is suitable for overhead lines rated at 35 kV and below; it is often used in conjunction with insulating covers to provide electrical insulation protection. The NLD series offers higher mechanical strength and is suitable for applications involving higher voltage levels and greater tension loads.

A: When making a selection, four key factors must be considered: 1) Conductor cross-section and diameter-ensure these fall within the clamp's applicable range; 2) Line rated tension-ensure the clamp's ultimate tensile strength (20–90 kN) meets the required specifications; 3) Voltage level-confirm compatibility with lines operating at 10 kV, 35 kV, 110 kV, or similar levels; 4) Environmental conditions-for coastal or high-salinity fog regions, select models featuring enhanced anti-corrosion coatings (such as hot-dip galvanization).