Specifications

28
Unit Design
Plug-in Unit Design Features
Plug-in units consist of the unit, unit support pan and unit door. Plug-in units are
held securely in the section when inserted and are designed with an interlock to
help ensure that units cannot be inserted or withdrawn when the disconnect
means is in the ON/I position.
Frame Mounted Unit Design Features
Frame mounted units are permanently mounted in the section, all connections
are made directly to the components. Fixed units range from 1 space factor to 6 space factors.
Disconnect Handle Mechanism
Flange style disconnect handles (vertical or horizontal mounted) are provided with
units with disconnects.
The disconnect handle of all units is interlocked with the unit door so the disconnect
means cannot be switched to the ON/I position unless the door is closed. This
interlock also prevents you from opening the unit door unless the disconnect is in the
OFF/O position. An externally operated defeater is provided if access to the unit is
needed without interrupting service. The interlock also prevents the unit from being
inserted or removed when the disconnect handle is in the ON/I position.
Unit Disconnect
Fusible disconnect switches are available in MCC units. The fusible disconnect switches have visible blade type movable
contacts and supplied with Class J, R, H, L, HRCII-C or CC fuse clips. NEMA space saving starter units are limited to Bulletin
194R fusible disconnect switch with Class CC fuse clips. Fusible disconnect requirements above 400A use a bolted pressure
contact switch with visible blade disconnect mechanism.
Circuit breaker disconnects are available in MCC units. Horsepower rated MCC units are provided with instantaneous
circuit breakers (HMCP) or with inverse time (thermal magnetic or electronic) circuit breakers. Current rated units are
provided with inverse time (thermal magnetic or electronic) circuit breakers.
Unit
Unit Door
Unit Support Pan