MT 8 - TC 121/SC 121A/MT 8

IEC 60947-7-4:2019 is available as IEC 60947-7-4:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 60947-7-4:2019 specifies requirements for PCB terminal blocks primarily intended for industrial or similar use. Mounting and fixing on the printed circuit board is made by soldering, press-in or equivalent methods to provide electrical and mechanical connection between copper conductors and the printed circuit board. This document applies to PCB terminal blocks intended to connect copper conductors, with or without special preparation, having a cross-section between 0,08 mm2 and 300 mm2 (AWG 28-600 kcmil), intended to be used in circuits of a rated voltage not exceeding 1 000 V AC up to 1 000 Hz or 1 500 V DC. This second edition cancels and replaces the first edition published in 2013. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) additional test for PCB terminal blocks with clamping units, where contact pressure is transmitted through insulating materials;
b) tightening torques for screws now given in Table 4 of this document (previously given in Table 4 of IEC 60947-1:2007); tightening torques added for an additional type of screw;
c) new criteria for verification of contact resistance introduced;
d) clarification in the description of the temperature-rise test (current-temperature derating); corrections in the test sequence according to Figure 4.

IEC 60947-7-4:2013 specifies requirements for PCB terminal blocks primarily intended for industrial or similar use. Mounting and fixing on the printed circuit board is made by soldering, press-in or equivalent methods to provide electrical and mechanical connection between copper conductors and the printed circuit board. This standard applies to PCB terminal blocks intended to connect copper conductors, with or without special preparation, having a cross-section between 0,05 mm2 and 300 mm2 (AWG 30/600 kcmil), intended to be used in circuits of a rated voltage not exceeding 1 000 V a.c. up to 1 000 Hz or 1 500 V d.c.

IEC 60947-7-1:2009 specifies requirements for terminal blocks with screw-type or screwless-type clamping units primarily intended for industrial or similar use and to be fixed to a support to provide electrical and mechanical connection between copper conductors. lt applies to terminal blocks intended to connect round copper conductors, with or without special preparation, having a cross-section between 0,2 mm2 and 300 mm2 (AWG 24/600 kcmil), intended to be used in circuits of a rated voltage not exceeding 1 000 V a.c. up to 1 000 Hz or 1 500 V d.c. This standard may be used as a guide for
- terminal blocks requiring the fixing of special devices to the conductors, for example quick connect terminations or wrapped connections, etc.;
- terminal blocks providing direct contact to the conductors by means of edges or points penetrating the insulation, for example insulation displacement connections, etc.;
- special types of terminal blocks, for example with diodes or varistors or similar component holders, 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:
- added in the scope that this standard may be used as a guide for special types of terminal blocks, for example with diodes or varistors or similar component holders;
- the conventional free air thermal current added in 5.2 in the list of information to be stated by the manufacturer;
- update of 7.1.4 that the colour combination green-yellow is not allowed for terminal blocks;
- the consequences in case of failed single tests and failed tests within test sequences specified in 8.2;
- requirements regarding clearances and creepage distances replaced by reference to Annex H of IEC 60947-1, Annex A deleted;
- requirements for tightening torques for the tests improved and referenced to Table 4 of IEC 60947-1, Annex C deleted;
- in 8.3.3.3 changed reference for pull-out force to IEC 60947-1;
- the wording of the test of the voltage drop improved in 8.4.4;
- the wording of the short-time withstand current test improved in 8.4.6;
- Annex D with additional requirements for test disconnect terminal blocks added. The scope modified accordingly.
This publication shall be read in conjunction with IEC 60947-1:2007.

IEC 60947-7-2:2009 specifies requirements for protective conductor terminal blocks with PE function up to 120 mm2 (250 kcmil) and for protective conductor terminal blocks with PEN function equal to and above 10 mm2 (AWG 8) with screw-type or screwless-type clamping units, primarily intended for industrial applications. Protective conductor terminal blocks are used to form the electrical and mechanical connection between copper conductors and the fixing support. lt is applicable to protective conductor terminal blocks for the connection of round copper conductors with or without special preparation having a cross-section between 0,2 mm2 and 120 mm2 (AWG 24 and 250 kcmil), intended to be used in circuits of a rated voltage not exceeding 1 000 V a.c. up to 1 000 Hz or 1 500 V d.c., most commonly in conjunction with terminal blocks according to IEC 60947-7-1. This standard may be used as guide for
- protective conductor terminal blocks requiring the fixing of special devices to the conductors, for example quick connect terminations or wrapped connections, etc.;
- protective conductor 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 for tightening torques for the tests improved and referenced to Table 4 of IEC 60947-1, Annex B deleted;
- the wording of the short-time withstand current test improved in 8.4.6.
This publication shall be read in conjunction with IEC 60947-1:2007 and IEC 60947-7-1:2009.

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 8.3.3.1;
- 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 8.5.2.5.
This publication shall be read in conjunction with IEC 60947-1:2007 and IEC 60947-7-1:2009.

IEC 60999-2:2003 Applies to screw-type and screwless-type clamping units for connecting devices, either as separate entities or as integral parts of equipment, for the connection of electrical copper conductors (complying with IEC 60228), rigid stranded and/or flexible, having a cross-section above 35 mm2 and up to and including 300 mm2 and equivalent AWG/kcmil sizes with a rated voltage not exceeding 1 000 V a.c. and a frequency up to and including 1 000 Hz and 1 500 V d.c. It applies to clamping units primarily suitable for connecting unprepared conductors. This standard does not apply to clamping units:
- for connection by crimping or soldering;
- for non-universal clamping units defined in 3.10.2 of IEC 60999-1.
It has the status of a group safety publication in accordance with IEC Guide 104.