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WL Circuit Breaker
ETU Function Overview
Basic functions
Long-time overcurrent protection
Function can be disabled
Setting range I
Switch-selectable overload protection (I
Setting range of time delay class t
(seconds)
L
Setting range of time delay t
(seconds)
Thermal memory
Phase loss sensitivity
Neutral protection
N
Function can be disabled
N-conductor setting range I
Short-time overcurrent protection
Function can be disabled
Setting range I
S
Setting range of time delay t
(constant time in seconds)
Setting range of time delay I
(seconds)
Zone Selective Interlocking (ZSI) function
Instantaneous overcurrent protection
Function can be disabled
I
Extended Instantaneous Protection
Setting range I
Ground fault protection
Trip and alarm function
Detection of the ground fault current
by residual summing method
Detection of the ground fault current
G
by direct sensing method
Setting range of the I
Setting range of the I
Setting range of the time delay t
(fixed seconds)
Setting range time delay t
ZSI ground function
1
Extended Instantaneous Protection (EIP) allows the WL breaker to be applied at the withstand rating
of the breaker with minus 0% tolerance; that means no instantaneous override whatsoever. EIP further
enables the circuit breaker to be applied up to the full instantaneous rating of the breaker on systems
where the available fault current exceeds the withstand rating.
2
Ground Fault Module cannot be removed after installation.
WL Circuit Breaker Selection and Application Guide
Courtesy of NationalSwitchgear.com
= I
x ...
R
n
2
t or I
4
t dependent function)
at I
2
t
R
at I
4
t
R
= I
x ...
n
N
= I
x ...
n
sd
, fixed
sd
2
at I
t
sd
= I
x ...
n
i
2
for trip
g
for alarm
g
g
2
at I
t
g
ETU745
–
0.4, 0.45, 0.5, 0.55, 0.6,
0.65, 0.7, 0.8, 0.9, 1
2, 3.5, 5.5, 8, 10,
14, 17, 21, 25, 30
1, 2, 3, 4, 5
(via slide switch)
set t
=20 ms (M)
sd
(via slide switch)
0.5 ... 1
(via rotary switch)
1.25, 1.5, 2, 2.5,
3, 4, 6, 8, 10, 12
0.02 (M), 0.1, 0.2,
0.3, 0.4, OFF
0.1, 0.2, 0.3, 0.4
per CubicleBUS module
Instantaneous is active when disabled
1.5, 2.2, 3, 4, 6, 8, 10, 12
0.8 x I
= Max,
cw
(field installable module)
O
A, B, C, D, E (100 ... 1200A)
A, B, C, D, E (100 ... 1200A)
0.1, 0.2, 0.3, 0.4, 0.5
0.4, 0., 0.3, 0.4, 0.5
per CubicleBUS module
available
–
not available
optional
13
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Do you have a question about the ETU745 and is the answer not in the manual?
Questions and answers
How do we field exchange an ETU745 breaker? The existing 1600 amp 120/208 volt breaker goes into alarm at about 750 amps and sometimes trips. We've hired a company to evaluate. Can this breaker be removed and replaced in the field?
Yes, the Siemens ETU745 breaker can be retrofit with a ground fault protection module, which implies that it is designed to allow field modifications such as removal and replacement.
This answer is automatically generated