1.1 Function
Protection of circuits against short-circuit currents,
Protection of circuits against overload currents,
Switch, isolation.
NB1 circuit-breakers are used in domestic installation,
as well as in commercial and industry electrical
Distribution systems.
1.2 Selection
Technical data of the network at the point considered:
Short-circuit current at the circuit-breaker installation point,
Which must always be less than the breaking capacity of
this device, network normal voltage.
Tripping curves:
B curve (3-5In)
Protection for people and big length cables in TN and IT systems.
C curve (5-10In)
Protection for resistive and inductive loads with low inrush current.
D curve(10-14In)
Protection for circuits which supply loads with high inrush
current at the circuit closing
(LV/LV transformers, breakdown lamps).