This International Standard applies to residual current operated circuit-breakers functionally independent of, or functionally dependent on, line voltage, for household and similar uses, not incorporating overcurrent protection (hereafter referred to as RCCB's), for rated voltages not exceeding 440 V a.c. and rated currents not exceeding 125 A, intended principally for protection against shock-hazard.These devices are intended to protect persons against indirect contact, the exposed conductive parts of the installation being connected to an appropriate earth electrode. They may be used to provide protection against fire hazards due to a persistent earth fault current, without the operation of the overcurrent protective device.RCCB's having a rated residual operating current not exceeding 30 mA are also used as a means for additional protection in case of failure of the protective means against electric shock.This standard applies to devices performing simultaneously the functions of detection of the residual current, of comparison of the value of this current with the residual operating value and of opening of the protected circuit when the residual current exceeds this value.NOTES1 The requirements for RCCB's are in line with the general requirements of IEC 755. RCCB's are essentially intended to be operated by uninstructed persons and designed not to require maintenance. They may be submitted for certification purposes.2 Installation and application rules of RCCB's are given in IEC 364.NOTE 201 The adoption of IEC Standards for portable and socket-outlet devices is under consideration. However, until they are published, this Standard and AS/NZS 3112, for socket-outlet devices, and this Standard and AS 3190, for portable devices, may be used by testing to selected clauses.3 RCCB's within the scope of the present standard are considered as suitable for isolation (see 8.1.3).Special precautions (e.g. lightningarresters) may be necessary when excessive overvoltages are likely to occur on the supply side (for example in the case of supply through overhead lines) (see IEC 364-4-443).NOTE 4 - For RCCB's having a degree of protection higher than IP20 special constructions may be required.Particular requirements are necessary for- Residual current operated circuit-breakers with integral overcurrent protection (see IEC 1009);- RCCB's incorporated in or intendedonly for association with plugs and socket-outlets or with appliance couplers for household or similar general purposes.NOTE 5 - For the time being, for RCCB's incorporated in, or intended only for socket-outlets or plugs, the requirements of this standard in conjunction with the requirements of IEC 884-1 may be used as far as applicable.The requirements of this standard apply for normal environmentalconditions (see 7.1) . Additional requirements may be necessary for RCCB's used in locations having severe environmental conditions.RCCB's including batteries are not covered by this standard.