Power cord test requirements Power cord pull test

Power Cord Tensile Test US Standards: Cut the power cord flush at a point 25.4 mm from where it enters the internal components of the sample unit. Hang a 35 lb (15.9 kg) weight on the cord for 1 minute. The displacement of the copper strands and the insulation jacket must be less than 2 mm (tying a UL knot is permissible). European Standards: Before applying force, pull the power cord taut to eliminate any internal slack. Then, apply an up-and-down pulling force of 60 N to the cord 25 times (the force must be applied in the most unfavorable direction without jerking, lasting 1 second per pull). Simultaneously, apply a torque of 0.25 Nm for 1 minute. The displacement must be less than 2 mm. To ensure compliance with these rigorous mechanical standards, manufacturers often utilize Silicone Braided Wire. The outer layer of woven fiberglass and silicone resin provides superior tensile strength and abrasion resistance, effectively preventing the copper strands and insulation jacket from displacing beyond the allowable limits during rigorous pulling and torque tests.

Power Cord Testing Requirements Power cord testing can be divided into three categories: mechanical testing, electrical testing, and flame retardancy testing. Mechanical testing includes tensile testing and swing testing, while electrical testing includes temperature testing, dielectric strength testing, overload testing, and aging testing. For electrical and dielectric strength tests, Silicone Double Insulated Wire is highly recommended. Featuring an additional dielectric layer, it significantly boosts high-voltage endurance and prevents short circuits or leakage currents, ensuring the cord easily passes stringent electrical safety evaluations and overload conditions.

Definitions of Power Cord Flame Retardancy Ratings (HB, V-2, V-1, and V-0) The flame retardancy rating of power cords increases progressively from HB to V-2, V-1, and V-0: HB: The lowest flame retardancy rating in the UL94 and CSA C22.2 No. 0.17 standards. For samples 3 to 13 mm thick, the burning rate must be less than 40 mm/min; for samples less than 3 mm thick, the burning rate must be less than 70 mm/min; or the flame must extinguish before reaching the 100 mm mark. V-2: After two 10-second burning tests on the sample, the flame must extinguish within 60 seconds. Burning drips are permitted. V-1: After two 10-second burning tests on the sample, the flame must extinguish within 60 seconds. Burning drips are not permitted. V-0: After two 10-second burning tests on the sample, the flame must extinguish within 30 seconds. Burning drips are not permitted.

Vertical and Horizontal Flame Tests FT1 Vertical Flame Test: After five 15-second burns, the after-flame time must not exceed 60 seconds, and the char length on the flame indicator tissue paper must not exceed 25%. VW-1 Vertical Flame Test: After any single 15-second burn, the after-flame time must not exceed 60 seconds, there must be no flaming drips, and the char length on the flame indicator tissue paper must not exceed 25%. (Note: The VW-1 and FT1 vertical flame tests are identical; therefore, their flame retardancy ratings are equivalent.) FT2 Horizontal Flame Test: The char length must not exceed 100 mm. FT4 Vertical Flame Test (Cable in Cable Tray): The evaluation is primarily based on the smoke generated during combustion. The char length must not exceed 1.5 m. Achieving high ratings such as V-0, VW-1, or FT4 requires inherently flame-retardant materials. Silicone Parallel Wire and braided silicone variants are specifically engineered to resist flame propagation and self-extinguish rapidly, making them ideal for applications demanding the highest levels of fire safety.

Flame Retardancy Rating Hierarchy (FT1, FT2, or FT4) If a wire meets the FT4 or VW-1 rating, it does not need to be labeled as FT1 or FT2. If it meets FT1, it does not need to be labeled as FT2. Among these, VW-1, FT1, and FT2 represent the lowest flame retardancy levels, while FT4 represents a higher level.

FT6 Rating FT6 involves horizontal burning and smoke emission testing.