This part of IEC 60947 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. This document can be used for terminal blocks for connection between aluminium conductors or aluminium to copper conductors. It applies to terminal blocks intended to connect round conductors, with or without special preparation, having a cross-section between 2,5 mm2 and 300 mm2 (AWG 12 to 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 document can be used as a guide to qualify terminal blocks for conductors out of aluminium not complying with IEC 60228 (e.g. smaller than 10 mm2, flexible or other materials). This document can also be used as a guide to qualify other types of terminal blocks for conductors out of aluminium other than feed through terminal blocks (e.g. partially insulated terminal blocks).

NOTE 1 AWG is the abbreviation of American Wire Gage (Gage (US) = Gauge (UK)).
kcmil = 1 000 cmil;
1 cmil = 1 circular mil = surface of a circle having a diameter of 1 mil;
1 mil = 1/1 000 inch.

This document does not apply to clamping units:
- dedicated to any other types of switchgear and controlgear;
- for connection by crimping, brazing, soldering or welding;
- for data and signalling circuits;
- for flat quick-connect terminations, insulation-piercing connecting devices and twist-on connecting devices, for which separate parts are under consideration.

NOTE 2 In case of use of special types of conductors (e.g. cladded conductors) which require a special preparation, this document can be used as a guide. 

NOTE 3 In some countries, national regulation for installation rules can allow different cross-sections. For internal wiring (inside enclosures), other rules or product standards can be applicable.

NOTE 4 For connections to copper conductors only, IEC 60947-7-1:2009 is applicable.

NOTE 5 In USA, UL 1059 applies and in Canada, CSA C22.2 No. 158 applies.

Where applicable in this document, the term clamping unit is used instead of the term terminal. This is taken into account in case of reference to IEC 60947-1:2020.