9. Multifunction testers

9.1 Purpose of multifunction testers

These devices are designed to provide a qualitative, on/off indication of the essential characteristics of the electrical quantities to be known when operating or maintaining electrical installations, in particular :

• polarity of DC voltages or diodes ;

• presence and order of magnitude of alternating voltages ;

• order of phases in a three-phase network ;

• insulation quality ;

• continuity of ground connections.

They are indicated by light and/or sound, notably when predetermined voltage or resistance thresholds are crossed or not....