DIN EN 50550:2011-11

This European Standard applies to power frequency overvoltage protection devices (POP) for household and similar uses, with a rated frequency of 50 Hz, a rated voltage 230 V a.c. (between phase and neutral), intended to be used in combination with a main protective device being either a circuit breaker (CB) in compliance with EN 60898-1 or EN 60898-2, a residual current circuit breaker (RCCB) in compliance with EN 61008-1 or a residual current circuit breaker with overcurrent trip (RCBO) in compliance with EN 61009-1. Requirements for POPs in combination with switching devices other than a main protective device, or a POP integrated in a MPD, are under consideration. Requirements for POP with functional earth connection regarding temporary overvoltage withstand are under consideration. A POP is not a protective device to be used for automatic disconnection of the supply in the meaning of HD 60364-4-41. They are intended for use in an environment with pollution degree 2 and overvoltage category III. They can be designed for factory assembly or for assembly on site. These devices are intended to mitigate the effects of power frequency overvoltages between phase and neutral conductor (for example, caused by loss of neutral conductor in the three phase supply upstream the POP) for downstream equipment by actuating the main protective device when an overvoltage between phase and neutral is detected. To mitigate means in this context that in most cases the POP will provide protection against power frequency overvoltages. Protection in case of overvoltage between phases is under consideration. In case of phase to phase electrical supply system with rated voltage between phases 230 V a.c. and no neutral conductor, one line monitored POP in compliance to this standard can be used according to manufacturer's instruction. The POP does not impair the protective function of the main protective device. The European Standard does not apply for protection against common mode over voltages. The European Standard does not apply to surge protective devices. This European Standard states: - the definitions of terms used for POP (clause 3); - the classification of POP (clause 4); - the characteristics of POP (clause 5); - the preferred values of the operating and influencing quantities (clause 5); - the marking and information to be provided for POP (clause 6); - the standard conditions for installation and operation in service (clause 7); - the requirements for construction and operation (clause 8); - the list of minimum requirements to be tested (clause 9). The responsible subcommittees are UK 541.2 "Kleine Selbstschalter" ("Miniature circuit-breakers") and UK 541.3 "Fehlerstrom-Schutzeinrichtungen" ("Residual current devices") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.