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
122
Manual, 01/2019, L1V30435333-01
Electronic trip units ETU550 LSI and ETU850 LSI
ETU550 LSI 3-pole and 4-pole units:
ETU850 LSI 3-pole and 4-pole units:
Line protection - function LSI
The electronic trip units ETU550 and ETU850 have:
●
Adjustable parameter settings I
r
and t
ld
for overload protection (L)
●
Adjustable parameter settings I
sd
and t
sd
for short-time delayed short circuit protection (S)
●
Adjustable parameter setting I
i
for instantaneous short-circuit protection (I)
●
With 4-pole versions: adjustable parameter setting I
N
for neutral conductor protection (N)
can be activated optionally for 3-pole versions
