Magnum
1812.900A
43
4 DRAWOUT CIRCUIT BREAKER AND
CASSETTE
4.1 General
Chapter 3 discussed topics and features common to all
Magnum circuit breakers, no matter what the mounting
configuration. In this section, features unique to the
drawout configuration not covered elsewhere, including
the drawout cassette, are covered.
The installation and levering of a drawout circuit breaker
were discussed in Section 2. If necessary, review that
information, since it will not be repeated here.
4.2 Drawout
cassette
A drawout circuit breaker is used in combination with a
fixed drawout cassette (Figure 4-1); the drawout circuit
breaker is equipped with automatic primary disconnects
(Figure 4-2). The cassette provides all of the necessary
interfaces to the drawout circuit breaker including
automatic primary and secondary connections. For the
IEC circuit breaker a cassette style using horizontal stabs
and horizontal customer bus bar terminals is available as
standard (Figure 4-3). The cassette terminal connections
can be adapted to vertical bus bar connections with a
variety of optional vertical adapters.
Mounting locations for cell (TOC) switches, safety
shutters, mechanical interlocks and key interlocks are
provided on the cassette.
Figure 4-1: Drawout Circuit Breaker in Cassette
4.3
Drawout circuit breaker dimensions
The Magnum drawout circuit breaker connects to the
fixed primary stabs of the drawout cassette through the
primary finger clusters attached to the rear of the circuit
breaker. Three different frame sizes cover all Magnum
circuit breakers from an overall dimensional standpoint.
4.4
Drawout cassette dimensions
Cassette drawings provide all the dimensional
information required for all mounting configurations.
Figure 4-2: Drawout Circuit Breaker with Automatic Primary
Disconnects