Applications
3.1 Use of the 3VA UL molded case circuit breakers in line protection
3VA molded case circuit breakers with UL and IEC certification
124
Manual, 01/2019, L1V30435333-01
Short-time delayed short circuit protection S:
•
I
sd
Adjustable from 0.6 to 9 / 10 x I
n
I
sd
< 40 A: In steps of 0.5 A
I
sd
≥
100 A: In steps of 1 A
•
t
sd
Adjustable from 0.05 to 0.5 s:
in steps of 0.01 s
with a reference point of I
sd
= 8 x I
r
The curve shape I
2
t = constant can be deactivated.
Instantaneous short-circuit protection I:
•
I
i
Adjustable from 1.5 to 9 / 10 / 12 x I
n
(dependent on rated operational current
and frame size)
In steps of 1 A
Neutral conductor protection N:
The neutral conductor protection function is available only for 3-pole molded case circuit
breakers with external current transformer for N conductor for 4-pole molded case circuit
breakers.
•
I
N
Adjustable in steps of 1 A
3-pole circuit breakers with external current transformer for N conductor:
I
n
< 40 A: 0.4 to 1.6 x I
n
I
n
≥ 100 A: 0.2 to 1.6 x I
n
4-pole circuit breakers:
I
n
< 40 A: 0.4 to 1.6 x I
n
I
n
≥ 100 A: 0.2 to 1.0 or 1.5 / 1.6 x I
n
