Specified maximum disconnection time
The IEC 60364-4-41 specifies the maximum operating time of protective devices
used in TN system for the protection against indirect contact:
b For all final circuits with a rated current not exceeding 32 A, the maximum
disconnecting time will not exceed the values indicated in Figure F13
b For all other circuits, the maximum disconnecting time is fixed to 5s. This limit
enables discrimination between protective devices installed on distribution circuits
Note: The use of RCDs may be necessary on TN-earthed systems. Use of RCDs on
TN-C-S systems means that the protective conductor and the neutral conductor must
(evidently) be separated upstream of the RCD. This separation is commonly made at
the service entrance.