DANSK DSF/IEC 60898-3 ED1 PDF

This part of IEC 60898 applies to DC circuit-breakers, having a rated DC voltage not exceeding 440V, a rated current not exceeding 125 A and a rated short-circuit capacity not exceeding 10 000 A. These circuit-breakers are intended for the protection against overcurrents of wiring installations of buildings and similar applications; they are designed for use by uninstructed people and for not being maintained. They are intended for use in an environment with pollution degree 2. They are suitable for isolation. Circuit-breakers in compliance with this standard are suitable for use in TN, TT, and, under specific conditions, IT systems. This standard also applies to circuit-breakers having more than one rated current, provided that the means for changing from one discrete rating to another is not accessible in normal service and that the rating cannot be changed without the use of a tool. This standard does not apply to – circuit-breakers intended to protect motors; – circuit-breakers, the current setting of which is adjustable by means accessible to the user. For circuit-breakers having a degree of protection higher than IP20 according to IEC 60529, for use in locations where arduous environmental conditions prevail (e.g. excessive humidity, heat or cold or deposition of dust) and in hazardous locations (e.g. where explosions are liable to occur), special constructions may be required. For an environment with a higher pollution degree, enclosures giving the appropriate degree of protection should be used. Circuit breakers according to this standard have a high resistance against unwanted tripping, regardless whether caused by in-rush currents through loading of electronic loads or by switching operations in the circuit. NOTE: Circuit-breakers within the scope of this standard can also be used for protection against electric shock in case of a fault, depending on their tripping characteristics and on the characteristics of the installation. The criterion of application for such purposes is dealt with by installation rules. This standard contains all requirements necessary to ensure compliance with the operational characteristics required for these devices by type tests. It also contains the details relative to test requirements and methods of testing necessary to ensure reproducibility of test results.