Gives general minimum requirements, recommendations and information for the drafting and testing procedures of standards for residual current operated protective devices, intended to be used in DC systems having a rated voltage not exceeding 400 V DC and a rated current not exceeding 125 A, hereafter referred to as DC-RCDs.

This document provides general minimum requirements, recommendations and information for the drafting and testing procedures of standards for residual current operated protective devices, intended to be used in DC systems having a rated voltage not exceeding 400 V DC and a rated current not exceeding 125 A, hereafter referred to as DC-RCDs.

NOTE 1 This document can also be used as a guide for DC-RCDs with voltages up to 1 500 V DC.

This document is primarily intended to be used as a reference for drafting product safety standard for DC-RCDs.

This document cannot be used alone but is intended for use by technical committees in the preparation of standards for products similar to those mentioned in the scope of this standard.

This document applies to a device

• which detects a residual current,

• compares it to a reference value, and

• opens the contacts or poles when the residual current exceeds this reference value.

Any association of devices, each one of them performing separately one or two of the above-mentioned functions, but acting together in order to accomplish all three functions, is also covered by this document.

NOTE 2 RCMs (residual current monitor according to IEC 62020) whose purpose is to monitor an electrical installation and not to provide protection are not covered by this document and cannot be considered similar or equivalent to DC-RCDs.

DC-RCDs are intended to provide fault protection, the exposed conductive parts of the installation being connected to an appropriate earth electrode, in accordance with IEC 60364-4-41.

DC-RCDs having a rated residual operating direct current not exceeding 80 mA are also used as a provision for additional protection in case of failure of the protective means against electric shock.

In accordance with IEC 60364-4-42, residual current devices with a rated residual operating current not exceeding 300 mA can also be used to provide protection against fire hazards due to a persistent earth fault current.

DC-RCDs are suitable for isolation. They are suitable for all supply systems, with the exception of single-pole DC-RCDs with two current paths which are not suitable for use in IT systems.

DC-RCDs of the general type are resistant to unwanted tripping including the case where surge voltages (as a result of switching transients or induced by lightning) cause loading currents in the installation without occurrence of flashover.

NOTE 3 Installation and application rules of RCDs are given in IEC 60364 (all parts).

NOTE 4 Surge protective devices installed downstream of DC-RCDs and connected in common mode can cause unwanted tripping.