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Figure 8.6 - Schneider Electric’s low voltage moulded case
circuit breaker (MCCB) type Compact NSX

3 Make a written translation of the following:
The purpose of the isolating function is to cut off the supply
from all or a discrete section of the installation by separating the
installation or section from every source of electrical energy for
reasons of safety.
The key factor here is the opening distance. Isolation must be
guaranteed from pole to pole and from input to output, whether
this is by means of a visible isolation gap or by suitable design
features within the device (mechanical interlocking mechanism).
A device fulfills the isolating function stipulated under IEC
60947-1 when in the “Open” position the isolation at a defined
withstand voltage is assured between the open contacts of the main
circuit of the switchgear.
It must also be equipped with an indicator device in relation to
the position of the movable contacts. This position indicator must

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