) DC breakdown voltage Udc = 230 (+30 / -40) V; 
 2) Pulse breakdown voltage Umax ≤ 800V (1000V/μs voltage rise rate); 
 3) impact-resistant capacity of lightning: simulate lightning through the following test. In the pulse voltage 4KV, voltage waveform 10/700μs test 10 times every 1 min between two opposite polarity voltage impact, can work; 
 4) resistance to power induction (long line) capacity: voltage Uac (max) = f = 50HZ duration of 500ms test 5 times under 1 minute intervals, can work;