China Copper wire with double-layer enamel insulations under the GOST 21428-75 standard

Double-Layer Enamel Insulation & Key Voltage Resistance Parameters

The unique double-layer enamel insulation structure is the core feature of this product, with strictly controlled electrical performance indicators:

1. ‌Rated Voltage‌: The standard full-series products have a rated operating voltage of 450/750V, which can stably adapt to the voltage level of most medium and small industrial winding equipment in the CIS region.
2. ‌Dielectric Strength‌: The composite enamel coating has a dielectric strength of no less than 20kV/mm, and the total insulation thickness is precisely controlled according to the wire diameter, which can effectively isolate the potential difference between turns.
3. ‌Withstand Voltage Test‌: After the production is completed, the finished wire will pass the 2000V power frequency withstand voltage test for 5 minutes without breakdown, which is far higher than the basic test requirement of the GOST 21428-75 standard.
4. ‌Insulation Resistance‌: At the operating temperature of 70℃, the insulation resistance per kilometer of enameled wire is not less than 100MΩ, which can still maintain excellent insulation performance in high-humidity industrial environments.
5. The inner enamel layer provides strong adhesion to the copper conductor, preventing the coating from peeling off during tight winding operations; the outer enamel layer further enhances the overall voltage breakdown resistance, effectively eliminating the risk of turn-to-turn short circuit. This two-layer insulation design significantly improves moisture resistance and solvent corrosion resistance, far exceeding the performance of single-layer enameled wire in harsh industrial environments.

GOST 21428-75 Compliance Features

Fully aligned with the technical requirements of GOST 21428-75, this product passes all standard mandatory tests including pinhole detection, thermal shock resistance, winding flexibility and breakdown voltage verification. It is fully recognized for use in manufacturing and maintenance scenarios of traditional Russian-spec electrical equipment, such as large-scale industrial motors, power transformers, heavy-duty inductors and metallurgical electrical systems, eliminating the compatibility barrier for cross-border industrial supply.

Application Scenarios

This standard-compliant double-layer enameled copper wire is widely favored by manufacturers and maintenance service providers targeting the CIS market. It can be directly applied to the winding of various electrical equipment without additional process adjustment, ensuring high durability and operational reliability while reducing long-term maintenance costs for end users.wire