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.