IEC 60364-4-43:2008

FOREWORD
43 Protection against overcurrent
    430.1 Scope
    430.2 Normative references
    430.3 General requirements
431 Requirements according to the nature of the circuits
    431.1 Protection of line conductors
    431.2 Protection of the neutral conductor
    431.3 Disconnection and reconnection of the neutral conductor
          in multi-phase systems
432 Nature of protective devices
    432.1 Devices providing protection against both overload
          current and short-circuit current
    432.2 Devices ensuring protection against overload current only
    432.3 Devices ensuring protection against short-circuit
          current only
    432.4 Characteristics of protective devices
433 Protection against overload current
    433.1 Coordination between conductors and overload protective
          devices
    433.2 Position of devices for overload protection
    433.3 Omission of devices for protection against overload
    433.4 Overload protection of conductors in parallel
434 Protection against short-circuit currents
    434.1 Determination of prospective short-circuit currents
    434.2 Position of devices for short-circuit protection
    434.3 Omission of devices for protection against short-circuit
    434.4 Short-circuit protection of conductors in parallel
    434.5 Characteristics of short-circuit protective devices
435 Coordination of overload and short-circuit protection
    435.1 Protection afforded by one device
    435.2 Protection afforded by separate devices
436 Limitation of overcurrent by characteristics of supply
Annex A (informative) Protection of conductors in parallel against
                      overcurrent
Annex B (informative) Conditions 1 and 2 of 433.1
Annex C (informative) Position or omission of devices for
                      overload protection
Annex D (informative) Position or omission of devices for
                      short-circuit protection
Annex E (informative) List of notes concerning certain countries
Bibliography

IEC 60364-4-43:2008 provides requirements for the protection of live conductors from the effects of overcurrents. IEC 60364-4-43:2008 describes how live conductors are protected by one or more devices for the automatic disconnection of the supply in the event of overload (Clause 433) and short-circuit (Clause 434) except in cases where the overcurrent is limited in accordance with Clause 436 or where the conditions described in 433.3 (omission of devices for protection against overload) or 434.3 (omission of devices for protection against short-circuit) are met. Coordination of overload protection and short-circuit protection is also covered (Clause 435). This third edition cancels and replaces the second edition, published in 2001, and constitutes a technical revision. The main changes with respect to the previous edition are:
- Introduction of new informative Annexes B, C and D.
- Information concerning flexible cables added to Scope.
- Requirements added for overload detection for the neutral conductor for harmonic currents.
- Requirement that devices for protection against short-circuit current be capable of making as well as breaking short-circuit current added.
- Information added to clarify protection against overload current.
- Requirements where devices for protection against overload need not be provided expanded.
- Requirements where devices for protection against short-circuit need not be provided expanded.
- Requirements for short-circuit current ratings of busbar trunking systems added.The contents of the corrigendum of October 2008 have been included in this copy.