Over deze norm
||Werkvoorschriften - NEC 623
Specifies physical requirements and tests on covers. Is applicable to rigid insulating covers including those described in IEC 743. The bariers, having dielectric withstand which depends on the positioning clearance, are excluded. Six classes are provided which differ in electrical characteristics. Moreover, five categories differing in special properties related to acid, oil, extreme low temperature, extreme high temperature, and humidity are provided.