How must switching devices be protected against overload and short-circuits? What regulation determines whether miniature circuit breakers / circuit breakers or fuses have to be used?
ANSWER:
The regulation IEC 60364-4-43 is applicable here. It permits the use of both fuses and miniature circuit breakers or circuit breakers. The permissible short-circuit protection of the control supply voltage of switching devices is frequently described in the operating instructions or in the device manual.
If not, no special rules have to be observed, and the planner of the installation has to dimension the protection according to the conditions of use (total current, cable length, cable cross-section, etc.).