Specifications

PIP ELCGL01
Electrical Design Criteria November 2002
Page 12 of 20 Process Industry Practices
7.2.3 If an MCC must be located in a building or room within a Class I, Division 2
area, the building or room shall be purged and/or pressurized per NFPA 496
to allow the use of general purpose equipment.
7.2.4 Where MCCs must be located outdoors in non-classified areas, they shall be
supplied with NEMA 3R enclosures unless specified otherwise on the Data
Sheet.
7.2.5 MCCs shall be supplied in front-only or back-to-back configurations as
specified on the Data Sheet.
7.2.6 Floor space shall be allocated for 20% potential MCC growth, unless
otherwise indicated on the Data Sheet.
7.2.7 Where groups of individual motor starters are located outdoors, they shall be
mounted on switchracks.
7.2.8 Individual motor starters located outdoors in non-classified areas shall be
supplied with NEMA 4X enclosures unless specified otherwise on the Data
Sheet.
7.2.9 Motor starters located in classified areas shall have explosion-proof
enclosures. Enclosures shall be bolted type unless otherwise specified on the
Data Sheet. Explosion-proof starters shall be applied within the short-circuit
rating of the starter assembly as listed by an NRTL.
7.2.10 The methodology of interfacing between the MCC and the control system is
outside the scope of this document and shall be specified separately.
7.2.11 The minimum starter size shall be NEMA Size 1 unless specified otherwise
on the Data Sheet.
7.2.12 Motors shall be protected by ambient-compensated, bi-metallic NEMA
Class 20 motor overloads unless specified otherwise on Data Sheet.
7.3 Low-Voltage Adjustable Speed Drives
Low-voltage adjustable speed drives shall be as specified in PIP ELSMC20 unless
specified otherwise on the Data Sheet. Adjustable speed drives, motors, and
associated equipment shall be designed as a coordinated system and according to
manufacturer recommendations.
7.4 Medium-Voltage Motor Control
7.4.1 For 2.3-kV and 4-kV motors, refer to the Data Sheet for the horsepower
range where circuit breakers are to be used as motor starters.
7.4.2 Where contactors are used as motor starters, they shall be Class E2 fused
contactors. Contactors shall be drawout (roll out), unless specified otherwise
on the Data Sheet. A separate isolation switch shall be provided.
7.4.3 Medium-voltage motors greater than 7.2 kV shall be controlled using 15-kV
class or higher switchgear.
7.4.4 Medium-voltage motor starters shall be specified according to
PIP ELSMC11 unless specified otherwise on the Data Sheet.