Rockwell Automation 284D ArmorStart - Getting Started - Manual (Page 17)

Publication 284D-QS001D-EN-P - July 2006
17
Group Motor Installations for USA and Canada Markets
The ArmorStart Distributed Motor controllers are listed for use with each
other in group installations per NFPA 79, Electrical Standard for Industrial
Machinery. When applied according to the group motor installation
requirements, two or more motors, of any rating or controller type, are
permitted on a single branch circuit. Group Motor Installation has been
successfully used for many years in the USA and Canada.
Wiring and Workmanship Guidelines
In addition to conduit and seal-tite raceway, it is acceptable to utilize cable
that is dual rated Tray Cable, Type TC-ER and Cord, STOOW, for power
and control wiring on ArmorStart installations. In the USA and Canada
installations, the following guidance is outlined by the NEC and NFPA 79.
In industrial establishments where the conditions of maintenance and
supervision ensure that only qualified persons service the installation, and
where the exposed cable is continuously supported and protected against
physical damage using mechanical protection, such as struts, angles, or
channels, Type TC tray cable that complies with the crush and impact
requirements of Type MC (Metal Clad) cable and is identified for such use
with the marking Type TC-ER (Exposed Run)* shall be permitted between
a cable tray and the utilization equipment or device as open wiring. The
cable shall be secured at intervals not exceeding 1.8 m (6 ft) and installed in
a “good workman-like” manner. Equipment grounding for the utilization
equipment shall be provided by an equipment grounding conductor within
the cable.
*Historically cable meeting these crush and impact requirements were
designated and marked “Open Wiring”. Cable so marked is equivalent to the
present Type TC-ER and can be used.
While the ArmorStart is intended for installation in factory floor
environments of industrial establishments, the following must be taken into
consideration when locating the ArmorStart in the application: Cables,
including those for control voltage including 24V DC and communications,
are not to be exposed to an operator or building traffic on a continuous
basis. Location of the ArmorStart to minimize exposure to continual traffic
is recommended. If location to minimize traffic flow is unavoidable, other
barriers to minimize inadvertent exposure to the cabling should be
considered. Routing cables should be done in such a manner to minimize
inadvertent exposure and/or damage.
Additionally, if conduit or other raceways are not used, it is recommended
that strain relief fittings be utilized when installing the cables for the control
and power wiring through the conduit openings.