Protection against indirect contact

Exposed-conductive-parts used in the manufacturing process of an electrical equipment is separated from the live parts of the equipment by the “basic insulation”. Failure of the basic insulation will result in the exposed-conductive-parts being alive.
Touching a normally dead part of an electrical equipment which has become live due to the failure of its insulation, is referred to as an indirect contact.

Contents

Measures of protection: two levels Automatic disconnection for TT system Automatic disconnection for TN systems Automatic disconnection on a second fault in an IT system Measures of protection against direct or indirect contact without automatic disconnection of supply