480V Metal-Enclosed Switchgear
LV Power Circuit Breakers
55CSI Section 16470
Siemens Electrical Products and Systems
Specification Guide
480V Metal-Enclosed
Switchgear
4
General
Ground Connection
A ground contact is located on the circuit
breaker to connect with the ground cir-
cuit. The breaker is grounded in both the
connected and test positions.
Drawout Interlocks
All circuit breakers have drawout inter-
locks to:
쐍 prevent racking a closed breaker
쐍 prevent closing breaker until racked to
connected or test position
쐍 prevent inserting or withdrawing
breaker from compartment while clos-
ing springs are charged
Arc Interruption
When a fault occurs, the main contacts
open first, transferring the fault current to
the arcing contacts. As the arcing con-
tacts open, the thermal and electromag-
netic characteristics force the arc into the
arc chute, where the metal plates length-
en, constrict, and cool the arc.
Current Limiting Fuses
The 800,1600 and 2000 ampere circuit
breakers are available with integrally
mounted current limiting fuses to
increase interrupting rating and / or to
limit short circuit (let-through) current.
The fuses are bolted in series with the
upper set of primary disconnects. The
breakers meet all required standards and
are UL Listed based on current limiting
fuses.
An open fuse tripping device is wired in
parallel with the main fuses to insure that
the circuit breaker opens if a main fuse
interrupts, thus preventing single phasing.
This device holds the circuit breaker trip-
free until it is reset and also indicates
which main fuse has interrupted.
The higher raed circuit breakers, 3200,
4000 and 5000 ampere, are available
with current limiting fuses mounted on a
separate drawout carriage, which is key
interlocked with the circuit breaker. This
allows racking of the fuse carriage with
only the associated circuit breaker in the
open position. The carriage mounts in the
same vertical section as the circuit break-
er element.
Current Sensors
The tripping system of the RL breaker is
self-powered from the current sensors
mounted on the primary contacts of the
breaker element (four-wire ground applica-
tions include a fourth sensor mounted in
the cable compartment). A signal from the
current sensors, proportional to primary
current, is applied to the trip device which
then operates the actuator to trip the
breaker based on a pre-set time delay
versus current magnitude relationship.
햲 Ground shoe contact
햳 Mounting rails
햴 Racking position detent
햵 Stored energy mechanism position
indicator
햶 Contact position indicator
햷 Arc chutes
햸 Handle for manually charging stored
energy closing springs (optional on
electrically operated breakers)
햹 Inter-phase barriers
햺 Racking mechanism shutter (with
packlocking provisions)
햻 Racking position indicator
햽 Contact closing release lever
(behind charging handle)
햾 Clevis attached to racking drive
screw.
햿 Circuit breaker rating nameplate
헀 Racking interlock bar
헁 Static Trip III trip unit test points
헂 Static Trip III overcurrent device
헃 Tripping lever (with padlocking
provisions) with guard.
헄 Breaker Display Unit (optional)
헅 Power switch for spring charging
motor (electrically operating break-
er only)
헆 Spring charging motor (electrically
operated breaker only)
Auxiliary switch (optional on man-
ually operated breakers)
Integrally Fused RLF-800 Circuit Breaker
RL Circuit Breaker Features (Electrically Operated Breaker Shown)
Sensor Ratings
Frame Size and
Max Amp Rating
800
150, 200, 300,
400, 600, 800
1600
2000
150, 200, 300, 400,
600, 800, 1200, 1600
150, 200, 300, 400,
600, 800, 1200, 1600, 2000
4000
3200 1200, 1600, 2000, 3200
햲
1600, 2000,
3200
햲
, 4000
햲
5000
5000
햲
Table 4.1 Available Sensor Ratings
햲
햲
Optionally available with integral 200A ground sensor
winding to meet NEC 239-95 requirements.
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