Siemens SENTRON 3VA1 Manual page 134

Applications
3.2 Line protection applications of 3VA molded case circuit breakers
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 ETU550 and ETU850 electronic trip units have:
● Adjustable parameter settings I
● Adjustable parameter settings I
● Adjustable parameter setting I
● With 4-pole versions: adjustable parameter setting I
(can be activated optionally with 3-pole versions when an external current transformer is
used for the neutral conductor)
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and t for overload protection (L)
r r
and t for short-time delayed short circuit protection (S)
sd sd
for instantaneous short-circuit protection (I)
i
N
3VA molded case circuit breakers with IEC certificate
for neutral conductor protection (N)
Manual, 03/2019, A5E03603177010-03