Specifications

Description
Frame Sizes and Ampere Ratings, Rating Plugs, and Interrupting Ratings
3
Frame Sizes and Frame Ampere Ratings
Siemens SB Encased Systems Breakers come in six frame
sizes with frame ampere ratings ranging from 400 to 5000
amperes. All frames are rated for 100% continuous operation.
The max ampere rating is determined by the current trans-
formers within the frame. Correctly rated electronic trip units
are available for all SB systems breakers.
Trip units are fully field installable by authorized personnel. A
special rejection scheme is built into the frames and trip units
to prevent the installation of a trip unit into a frame for which
it is not intended.The two-pin rejection scheme is shown on
page 7.The combinations of frame sizes and frame ampere
ratings are listed in the following table.
Rating Plugs
Field interchangeable rating plugs are used to set the effec-
tive ampere rating of the circuit breaker. Available rating plugs,
as a function of the frame ampere ratings, are given in the
following table. Note that the maximum rating plug value for
a particular electronic trip unit is equal to the frame rating;
the minimum is equal to 50% of the MAX Rating. A rejection
scheme is built into the rating plugs and trip units to prevent
the insertion of a rating plug into a trip unit for which it is not
intended.
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 pro-
vided by the trip unit allows the user to easily accommodate
load changes and other protection requirements while still
assuring optimum coordination.
A standard feature of the trip unit is RMS 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.
Interruption and Short Time Ratings
Four short circuit interruption ratings are available to meet
specific applications.The interruption ratings and short time
ratings are given in the following table:
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. Blue indicates
the “alternate” or the lowest interrupting category. Black indi-
cates the “standard”interrupting rating. A Red label indicates
the highest available interrupting rating for the SB breaker.
The trip unit that may be used with a specific circuit breaker is
identified on the front cover label.
NOTE: For trip units not requiring full-function adjust-
ability, integral testing functions, local indication, or
ACCESS communications compatibility, specify trip
unit with catalog suffix MLI.
Frame Size and Rating Combinations
Breaker Frame Ampere Size Breaker Max Ampere Rating
1200 Amperes 400, 800, 1200
(SBA, SBS only)
2000 Amperes 800 (SBH only), 1200, 1600, 2000
3200 Amperes 2500, 3200
5000 Amperes 2500, 3200, 4000, 5000
UL 489 Interruption and Short Time Ratings
Breaker Frame Size
1200 2000 3200 5000
Type SBA Alternative Interrupt Rating (Blue Label)
240V AC 65 kA 85 kA
480V AC 65 kA 65 kA — —
600V AC 42 kA 50 kA
Type SBS Standard Interrupt Rating (Black Label)
240V AC 100 kA 150 kA 150 kA 150 kA
480V AC 100 kA 100 kA 100 kA 100 kA
600V AC 50 kA 65 kA 85 kA 85 kA
Type SBH High Interrupt Rating (Red Label)
240V AC 200 kA 200 kA 200 kA
480V AC — 150 kA 150 kA 150 kA
600V AC 100 kA 100 kA 100 kA
Short Time Rating (t=0.5 seconds)
25 kA 35 kA 50 kA 65 kA
IEC 947-2 Ratings (SBS Units Only)
Frame Sizes
Voltage 50/60 Hz 1200 2000 3200 5000
Type SBS Standard Interrupt Rating (Black Label)
415V AC lcu 100 kA 100 kA 100 kA 100 kA
lcs 100 kA 100 kA 100 kA 100 kA
lcw 25 kA 35 kA 50 kA 65 kA
690V AC lcu 65 kA 65 kA 65 kA 65 kA
lcs 65 kA 65 kA 65 kA 65 kA
lcw 25 kA 35 kA 50 kA 65 kA
Available Rating Plugs
Ampere Rating Rating Plug Ampere Values (I
n
)
400 200, 225, 250, 300, 350, 400
800 400, 450, 500, 600, 700, 800
1200 600, 700, 800, 1000, 1200
1600 800, 1000, 1200, 1600
2000 1000, 1200, 1600, 2000
2500 1600, 2000, 2500
3200 1600, 2000, 2500, 3000, 3200
4000 2000, 2500, 3000, 3200, 4000
5000 2500, 3000, 3200, 4000, 5000