Abstract
IEC 60947-3:2008 applies to switches, disconnectors, switch-disconnectors and fuse-combination units to be used in distribution circuits and motor circuits of which the rated voltage does not exceed 1 000 V a.c. or 1 500 V d.c. This part does not apply to equipment coming within the scope of IEC 60947-2, IEC 60947-4-1 and IEC 60947-5-1; however, when switches and fuse-combination units coming into the scope of this part are normally used to start, accelerate and/or stop an individual motor they shall also comply with the additional requirements given in Annex A. The requirements for single pole operated three pole switches are included in Annex C. Auxiliary switches fitted to equipment within the scope of this part shall comply with the requirements of IEC 60947-5-1. This part does not include the additional requirements necessary for electrical apparatus for explosive gas atmospheres. This edition includes the following significant technical changes with respect to the previous edition:
- alignment with the fifth edition of IEC 60947-1;
- a switching operation without current allowed between making and breaking operation (Table 3);
- increased number of operations for AC-23 allowed with agreement of the manufacturer (Table 3);
- simplified test procedure amended, f) added to 8.3.2.1.3;
- temperature rise test shall be made at the rated operational current /e instead of the conventional enclosed thermal current /the (8.3.3.1).
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