circuit protectors (MCP's) instead of
thermal-magnetic circuit breakers, are offered as
standard by several major manufacturers; however,
the thermal-magnetic type is still offered as an
option. The MCP is designed especially for motor
circuits and will generally provide better
protection for motors, controllers, and circuit
conductors than the thermal-magnetic type. In any
case, one or the other should be specified, so that
all bids will be on the same basis. Generally,
thermal magnetic breakers should be specified for
reduced voltage starters because MCP do not have
high enough current settings to avoid nuisance
tripping from current inrush and switching
transients generated during start to run sequence.
This specification does not cover the use of fused
motor protection. Fuses are the least cost
alternative, but require more maintenance. They are
not recommended for powerhouse applications. Fuses
may be acceptable for other applications, provided
that suitable phase-voltage-unbalance protection for
motors is specified.
When PART 3 criteria are added for CONSTRUCTION
contracts, take care to prevent conflicts, gaps, or
omissions.
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The general arrangement of the motor control centers, switchboards and
panelboards is shown on the contract drawings. Any modifications of the
equipment arrangement or device requirements as shown on the drawings shall
be subject to the approval of the Contracting Officer. If any conflicts
occur necessitating departures from the drawings, details of and reasons
for departures shall be submitted and approved prior to implementing any
change. All equipment shall be completely assembled at the factory. The
motor control centers and switchboards may be disassembled into sections,
if necessary, for convenience of handling, shipping, and installation.
1.2.3
Standard Products
Material and equipment shall be standard products of a manufacturer
regularly engaged in their manufacture and shall essentially duplicate
items that have been in satisfactory use for at least 2 years prior to bid
opening. All materials shall conform to the requirements of these
specifications. Materials shall be of high quality, free from defects and
imperfections, of recent manufacture, and of the classification and grades
designated. All materials, supplies, and articles not manufactured by the
Contractor shall be the products of other recognized reputable
manufacturers. If the Contractor desires for any reason to deviate from
the standards designated in these specifications, he shall, after award,
submit a statement of the exact nature of the deviation, and shall submit,
for the approval of the Contracting Officer, complete specifications for
the materials which he proposes to use.
1.2.4
Nameplates
Nameplates shall be made of laminated sheet plastic or of anodized aluminum
approximately 4 mm 1/8 inch thick, engraved to provide white letters on a
SECTION 16403A
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