Development of LV circuit breakers to standard IEC 947-2

Advantages

Development of the need for safety and of technologies is responsible for a marked recovery of industrial circuit breaker standard requirements (circuit breakers whose implementation is reserved for electricians).

Today, conformity with standard IEC 947-2, published in 1989 and reviewed and completed in 1995, can be considered as an « all-risks insurance » guaranteeing a circuit breaker’s fitness for use. Quite remarkably all countries, except Japan, have approved this standard. Japan’s approval should be given in the near future.

This « Cahier Technique » presents the advantages of this standard over the former IEC 157-1, and describes the numerous tests to be satisfied by these breaking devices. These tests are highly representative of the constraints actually encountered in electrical installations.

Introduction

As with all electrical devices, industrial Low Voltage circuit breakers are designed, manufactured and verified according to rules collected in the standards known as « product standards » (see fig. 1 ). Each country has its own standards (UTE for France, BS for the UK, VDE for Germany, etc…), often derived from IEC (International Electrotechnical Commission) publications which have a reference purpose.

Consequently the standards covering LV industrial circuit breakers are today, in Europe as in a large number of other countries, based on the IEC 947-2 standard which, in 1989, replaced the 1973 standard IEC 157-1 (see fig. 2 ).

AUTHOR: Schneider Electric expert | Etienne BLANC