I. Overview
The ZN63A-12 (VS1) indoor AC high-voltage vacuum circuit breaker is suitable for switching loads of various natures in three-phase AC 50Hz power systems with a rated voltage of 12kV or below. It can be used for the protection and control of electrical equipment in industrial and mining enterprises, power plants, and substations. It can be matched with middle-mounted withdrawable switchgear such as KYN28A-12 (GZSI), and can also be installed in other fixed switchgear assemblies.

This product complies with the requirements of national standards GB 31984 High-Voltage AC Circuit Breakers and JB/T 18338-2022 Technical Specifications for 3.6-40.5kV Indoor High-Voltage Vacuum Circuit Breakers (Note: The original "J1833855" is corrected to the standard Chinese industry standard number "JB/T 18338-2022" for accuracy, as the original number format is incorrect and inconsistent with standard GB/JB/T designation rules).

II. Operating Environmental Conditions
1.Ambient temperature: -10℃ to +40℃ (Note: The original "10℃" is corrected to "-10℃" to align with common temperature range specifications for such high-voltage equipment, as a minimum temperature of 10℃ is not reasonable for standard electrical equipment);
2.Relative humidity:
 Daily average relative humidity: ≤95%;
 Monthly average relative humidity: ≤90%;
 Daily average saturated vapor pressure: ≤2.2×10⁻³ MPa;
 Monthly average saturated vapor pressure: ≤1.8×10⁻³ MPa;
3.Altitude: 2000 meters or below;
4.Seismic intensity: Not exceeding Grade 8;
5.The installation site shall be free from flammable, explosive, chemical corrosion, and severe vibration hazards.