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a. The mechanical engineer will determine which equipment will have
integral magnetic contactors and/or disconnect switches and which
equipment will require separate magnetic motor controllers and
disconnect switches. In general, packaged refrigeration equipment has
integral magnetic contactors and in some instances will have an
integral disconnect switch also. Air-handling units and pumps usually
require separate magnetic motor controllers and disconnect switches.
b. The electrical engineer, in conjunction with the mechanical engineer,
will determine the location of separate magnetic motor controllers and
disconnect switches. Magnetic motor controllers and disconnects shall
be placed in readily accessible locations (as defined by NFPA 70).
c. The electrical engineer will show separate magnetic motor controllers
and separate disconnect switches on the electrical drawings.
The electrical engineer will not provide any magnetic motor controller
information for mechanical equipment on the electrical drawings, but
will determine the type of controller required (full voltage, reduced
voltage, reversing, multi-speed, NEMA size, and NEMA enclosure
type) and furnish same to the mechanical engineer for incorporation in
mechanical equipment schedules. Mechanical equipment schedules
will also include electrical characteristics of motor and packaged
equipment; e.g., voltage, full load amperes or minimum circuit
amperes, number of phases, horsepower, and frequency. Integral
disconnects, if provided, shall be noted in the mechanical equipment
schedules and coordinated with the electrical drawings. Require
integral disconnects be furnished with thermal overloads where
appropriate for small fractional horsepower motors. The mechanical
specifications must be coordinated with the mechanical equipment
schedules and mechanical plans.
Electrical unit heaters will be sized and located by the mechanical engineer,
will be shown on the electrical drawings, noted and properly cross-referenced
on the mechanical drawings, and specified in the electrical specifications.
The electrical engineer must be alert for motors required for equipment
furnished by engineers other than mechanical. These include architectural
Attachment A-26


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