PURPOSE AND FEATURE 　　The products are suitable for opening or closing the line in case of having voltage and no-loak on the net-work of 10-15KV,three-phase AC,frequency 50HZ. RANGE OF USE Ambient temperature:no higher than +40℃,no lower than -30℃,no lower than -40℃ in high frigid zone. No more than 1000m above sea level Wind speed no more than 35m/s Earthquake strength not in excess of 8 degrees