Siemens 480V Ground Connection, Drawout Interlocks, Arc Interruption, Current Limiting Fuses

480V Metal-Enclosed Switchgear

LV Power Circuit Breakers

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:

Jprevent racking a closed breaker

Jprevent closing breaker until racked to connected or test position

Jprevent 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.

aGround shoe contact b Mounting rails

c Racking position detent

d Stored energy mechanism position indicator

e Contact position indicator f Arc chutes

g Handle for manually charging stored energy closing springs (optional on electrically operated breakers)

h Inter-phase barriers

i Racking mechanism shutter (with packlocking provisions)

j Racking position indicator k Contact closing release lever

(behind charging handle)

lClevis attached to racking drive screw.

mCircuit breaker rating nameplate n Racking interlock bar

o Static Trip III trip unit test points p Static Trip III overcurrent device q Tripping lever (with padlocking

provisions) with guard.

r Breaker Display Unit (optional) s Power switch for spring charging

motor (electrically operating break- er only)

t Spring charging motor (electrically

operated breaker only)

Auxiliary switch (optional on man- ually operated breakers)

4

480V Metal

RL Circuit Breaker Features (Electrically Operated Breaker Shown)

- Switchgear

Integrally Fused RLF-800 Circuit Breaker

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.

Table 4.1 Available Sensor Ratings a

Frame Size and
Max Amp Rating	Sensor Ratings
800	150, 200, 300,
	400, 600, 800
1600	150, 200, 300, 400,
	600, 800, 1200, 1600
2000	150, 200, 300, 400,
	600, 800, 1200, 1600, 2000
3200	1200, 1600, 2000, 3200 a
4000	1600, 2000,
	3200 a, 4000 a
5000	5000 a

aOptionally available with integral 200A ground sensor winding to meet NEC 239-95 requirements.

Enclosed

CSI Section 16470	Siemens Electrical Products and Systems	55
	Specification Guide