... of electricity,overload,breakdown,protect and so on. HPZ1-A-1series is suitable for use in mining industry,commerce, ... working condition:1,elevation is ≤2000m;2,ambient air T is ≤+40°c, ≥-25°c;3,when the highest ... ≤-25°c;when it is in th lower T,a little high T is allowed;when in the monthly which is ... more humidity time,the average T is ≤+25°c. operation and maintenance:1,HPZ1 ...