IEC 61557-11:2020 pdf download – Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V DC – Equipment for testing, measuring or monitoring of protective measures – Part 11: Effectiveness of residual current monitors (RCM) in TT, TN and IT systems.
3.8 residual current monitor RCM device or association of devices which monitors the residual current in an electrical installation, and which activates an alarm when the residual current exceeds the operating value of the device [SOURCE: IEC 62020-1 :2020, 3.1 .1 ] 3.9 RCM Type A type of RCM for which monitoring is ensured for residual sinusoidal alternating currents and residual pulsating direct currents, whether suddenly applied or slowly rising [SOURCE: IEC 62020-1 :2020, 5.2.6.2, modified – The words “initiating an alarm” have been replaced with “monitoring”.] 3.1 0 RCM Type B type of RCM for which monitoring is ensured for residual sinusoidal alternating currents, with residual pulsating direct currents and smooth residual direct currents independent of polarity, whether suddenly applied or slowly rising Note 1 to entry: RCM Type B are described in IEC 62020-1 :2020, 5.2.6.4. 3.1 1 directionally discriminating RCM type of RCM having the ability to discriminate between supply side and load side residual currents of the monitored lines, as declared by the manufacturer Note 1 to entry: Directionally discriminating RCM are described in IEC 62020-1 . [SOURCE: IEC 62020-1 :2020, 3.1 .1 0] 4 Requirements 4.1 General In addition to the requirements of IEC 61 557-1 :201 9, Clause 4, the requirements of Clause 4 of this document shall apply. 4.2 Functions 4.2.1 Operating test The testing equipment shall be capable of verifying that the residual operating current of an RCM Type A tested with an AC test current is less than or equal to the value of the rated residual operating current. Testing of an RCM Type A shall be conducted with a calibrated AC current suddenly applied at a zero crossing. The tests shall be carried out with a sinusoidal, or mains-derived quasi-sinusoidal, test current. If the test equipment is capable of producing half-wave test currents, testing of an RCM Type A may be carried out alternatively with half-wave test currents and/or AC current with superimposed ±6 mA DC.
In the case of pulsed DC current, the test equipment shall be capable of testing in both polarities. When testing an RCM Type B with a DC test current, it shall be verified that the residual operating current is less than or equal to 2 times the value of the rated residual operating current. Testing of an RCM Type B shall be conducted separately with a suddenly applied, calibrated AC current and a linearly increasing smooth direct current. The slope of the linear increase shall not be greater than 2 times I ∆n / 5 s. If the slope of the linear increase is simulated by a stepwise or linearly increasing test current; the increase shall not be greater than 2 times I ∆n / 30 (see Figure 1 to Figure 3). In both cases, the starting current shall be less than 0,2 times I ∆n . The operating uncertainty of the increasing test current I T shall not exceed ±1 0 % of the rated residual operating current I ∆n . The operating uncertainty of the calibrated test current I T shall not exceed 0 % to +1 0 % of the rated residual operating current I ∆n . The test period shall be adapted to the set actuating time of the RCM and it shall be possible to extend the test period up to 1 0 s.
4.2.3 Test of actuating time If the set actuating time of the RCM is being tested with the test equipment, the setting of the test period on the test device shall have a resolution of minimum 0,5 s ranging up to 1 0 s. The setting uncertainty shall not exceed 0 % to −1 0 % of the set value. The test shall solely be performed with calibrated AC test current. Other methods for the acquisition of the actuating time via optical recognition or interfacing are permissible. NOTE The general function of RCMs is not to disconnect the power supply when a residual current above the value of the rated residual operating current occurs. The RCM indicates the increase of the residual current above the residual operating current with a signalling device, for example a lamp, buzzer, contact relay or interface-signal. Thus, the response time can only be tested via the visual or additional electrical detection of this signal. According to IEC 62020-1 , the actuating time of the RCM may only amount to a maximum of 1 0 s. The response time shall be specified by the manufacturer or shall be adjustable on the device. If the RCM is being used for the purpose of disconnection, the tests covered by IEC 61 557-6 shall apply.