1.1 Function 

protection of circuits against short-circuit currents,
protection of circuits against overload currents,
switch, isolation.
NB8 -40J 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.
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(10-16In)
protection for circuits which supply loads with high inrush
current at the circuit closing
(LV/LV transformers, breakdown lamps).

1.3 Certificate
CE