Surge protective device is a kind of pre-installed distributing equipment. It can be used in mining, industrial company, gas field, new developing district, building ground, especially applies to city public distributing facility, high building distributor, esidential district and resort.

Its characteristics are as follows:

small size, convenience to operate in site, easy operation, high security, good outline and cooperative ability.

Surge protective device country used before was made from ordinary steel board, alumina alloy board and stainless steel.

Such problems were exsited: weak ability to anti-insulation, anti- radiation and anti-erosion, easy to tarnishing and condensation, so in recently years, non-metal (glass and fiber cement) material cabinet type substations are developed.