VS1-24 Series indoor high voltage vacuum circuit breaker , VCB, is improved ... the basis of VD4-24 of ABB Company VS1-24 Series indoor high voltage vacuum circuit breaker , alos called VCB, ... current 630A-3150A, rated short circuit drop-out current 20KA-31.5KA.4. mechanical endurance: 20,000 times.5. it ... 12KV voltage and 4,500 meters altitude. VS1-24 Series indoor high voltage vacuum circuit breaker(VCB)