The purpose of this standard is to harmonize as far as practicable all rules and requirements of a general nature to low-voltage switchgear and controlgear in order to obtain uniformity of requirements and tests throughout the corresponding range of equipment and to avoid the need for testing to different standards. All those parts of the various equipment standards which can be considered as general have therefore been gathered in this standard together with specific subjects of wide interest and application, e.g. temperature-rise, dielectric properties, etc. For each type of low-voltage, switchgear and controlgear, only two main documents are necessary to determine all requirements and tests: 1) this basic standard, referred to as "Part 1" in the specific standards covering the various types of low-voltage switchgear and controlgear; 2) the relevant equipment standard herinafter referred to as the "relevant product standard" or "product standard". For a general rule to apply to a specific product standard, it shall be explicitly referred to by the latter, by quoting the relevant clause or subclause number of this standard followed by "IEC 60947-1" e.g. "7.2.3 of IEC 60947-1". This standard applies, when required by the relevant product standard, to switchgear and controlgear herinafter referred to as "equipment" and intended to be connected to circuits, the rated voltage of which does not exceed 1 000 V a.c. or 1 500 V d.c.