General Information
Frame Sizes and Frame Ampere Ratings
SB breakers come in three frame sizes with frame ampere
ratings ranging from 400 to 4000 amperes. All frames are
rated for 1 00% continuous operation . This particular in
struction guide provides detailed SB breaker information
for the 4000 ampere frame size. Frame ampere ratings for
this size range from 2500 amperes to 4000 amperes.
Frame Sizes and Ratings Combinations
Breaker
Breaker
Frame Size
Frame Ampere Rating (1,)
4000 Amperes
2500 Amperes
3200 Amperes
4000 Amperes
Rating Plugs
SB breakers are designed to use interchangeable rating
plugs. These rating plugs allow the user to customize the
effective ampere rating of the breaker to meet specific
applications. The label on the front of the breaker identifies
the rating plugs that may be used with that particular
breaker.
Available Rating Plugs
Frame A mpere Ratings (1,)
Rating Plu g Valu es (Amperes) (1,)
2500
1 600,2000, 2500
3200
1 600, 2000, 2500, 3000, 3200
4000
2000,2500, 3000,3200, 4000
Interruption and Short Time Ratings
Two short circuit interruption ratings are available to meet
specific applications. The interruption ratings and short
time ratings are given in the following table.
UL Listed Interruption and Short Time Ratings
UL Listed
Frame Size
Label
Symmetrical A mperes
4000
Ampere
Color
Standard Interrupting Rating (kA)
@ 240V AC
1 50
Black
@ 480V AC
1 00
(SBS)
@ 600V AC
85
High Interrupting Rating (kA)
Red
@240V AC
200
@480V AC
1 50
(SBH)
@600V AC
1 00
Short Time Rating (kA)
65
........
T 0.5 sec
.' ·
The interruption rating of the SB breaker is specified on
the front cover label, and is further identified by the use of
a "color bar" at the top left of the breaker label.
Black
indicates the "standard" or middle i nterrupting rating.
A
Red
label indicates the highest available i nterrupting
rating for the SB breaker.
Overcurrent Protection Configurations
Siemens Electronic Trip Units for SB breakers are avail
able in six basic overcurrent protection configurations
to meet specific protection requirements. All trip units
come equipped with Adjustable Continuous Current and
Long Time Delay functions. Optional protection configura
tions are:
Protection Configuration
Long Time/Short Time
Long Time/Instantaneous
Long Time/Short Time/Instantaneous
Long Time/Short Time/Ground Fault
Long Time/ I nstantaneous/Ground Fault
Long Time/Short Time/Instantaneous/
G round Fau lt
Identifier
LS
Ll .
LSI
LSG
LIG
LSIG
The trip unit that may be used with a specific circuit breaker
is identified on the front cover label.
RMS Current Sensing
The Siemens microprocessor controlled Electronic Trip
Unit executes the overcurrent fault protection functions of
Siemens SB Encased Systems Breakers. The adjustment
flexibility provided by the trip unit allows the user to easily
accommodate load changes and other protection require
ments while still assuring optimum coordination. A standard
feature of the trip unit is RMS current sensing. As opposed
to peak-current sensing, RMS sensing measures the
true heating potential of the current waveform. This allows
for more accurate overcurrent protection and eliminates
nuisance tripping due to harmonic distortion of the
current waveform.
NOTE: For more complete information on other
standard and optional features of the Electronic
Trip Unit, see Siemens Electronic Trip Unit for SB
Encased Systems Breakers Information and
Instruction Guide, Bulletin 2.20-3A.
Accessories
A full family of i nternal, external, and remote accessories
are available for Siemens SB Encased Systems Breakers.
A breaker may be configured with all of the internal acces
sories without changing the external physical characteris
tics. Detailed descriptions oft he accessories are contained
in the Accessories section, pages 35-73.
3
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