International Electrotechnical Commission

Guidance concerning the permissible temperature rise for parts of electrical equipment, in particular for terminals - Edition 2.1 Consolidated Reprint
 N TR 60943

Annotation

Scope and object

This report is intended for guidance in estimating the permissible values for temperature and temperature rise of component parts of electrical equipment carrying current under steady state conditions.

This report applies to electrical power connections and materials adjacent to them.

This report is concerned with the thermal effects of currents passing through connections, therefore there are no voltage limits to its application.

This report is only applicable when referred to in the appropriate product standard.

The extent and manner to which the contents of this report are used in standards is the responsibility of individual Technical Committees.

Whenever "permissible" values are stated in this report, they mean values permitted by the relevant product standard.

The present report is intended to supply:

– general data on the structure of electric contacts and the calculation of their ohmic resistance;

– the basic ageing mechanisms of contacts;

– the calculation of the temperature rise of contacts and connection terminals;

– the maximum “permissible” temperature and temperature rise for various components, in particular the contacts, the connection terminals and the conductors connected to them;