IEC 60947-7-3:2009 applies to fuse terminal blocks with screw-type or screwless-type clamping units for the connection of rigid (solid or stranded) or flexible copper conductors for the reception of cartridge fuse-links in accordance with IEC 60127-2, intended primarily for industrial or similar use in circuits not exceeding 1 000 V a.c., up to 1 000 Hz or 1 500 V d.c., and having a maximum short-circuit breaking capacity of 1 500 A. They are intended for installation in electrical equipment with enclosures which surround the fuse terminal blocks to such an extent that they are accessible only with the aid of a tool. For certain applications, for example in control circuits, the fuse terminal blocks may be designed exclusively for short-circuit protection. The object of this standard is to specify safety requirements and test methods for the mechanical, electrical and thermal characteristics of fuse terminal blocks, to ensure the compatibility between terminal blocks and standardized fuse-links. This standard may be used as a guide for
- fuse terminal blocks requiring the fixing of special devices to the conductors, for example quick connect terminations or wrapped connections, etc.;
- fuse terminal blocks providing direct contact to the conductors by means of edges or points penetrating the insulation, for example insulation displacement connections, etc.
Where applicable in this standard, the term clamping unit has been used instead of the term terminal. This is taken into account in case of reference to IEC 60947-1. The main technical modifications of this standard since this previous publication are listed below:
- requirements regarding clearances and creepage distances replaced by reference to Annex H of IEC 60947-1;
- requirements for the test of the mechanical strength of the clamping units improved in 22.214.171.124;
- requirements for tightening torques for the tests improved and referenced to Table 4 of IEC 60947-1;
- requirements for the resistance and the dimensions of dummy fuse-links specified in 126.96.36.199.
This publication shall be read in conjunction with IEC 60947-1:2007 and IEC 60947-7-1:2009.