shall be No. 12 AWG. Special attention shall be given to wiring and
terminal arrangement on the terminal blocks to permit the individual
conductors of each external cable to be terminated on adjacent terminal
points.
2.4
TERMINAL BLOCKS
Control circuit terminal blocks for control wiring shall be molded or
fabricated type with barriers, rated not less than 600 volts. The
terminals shall be removable binding, fillister or washer head screw type,
or of the stud type with contact and locking nuts. The terminals shall be
not less than No. 10 in size and shall have sufficient length and space for
connecting at least two indented terminals for 10 AWG conductors to each
terminal. The terminal arrangement shall be subject to the approval of the
Contracting Officer and not less than four (4) spare terminals or 10
percent, whichever is greater, shall be provided on each block or group of
blocks. Modular, pull apart, terminal blocks will be acceptable provided
they are of the channel or rail-mounted type. The Contractor shall submit
data showing that the proposed alternate will accommodate the specified
number of wires, are of adequate current-carrying capacity, and are
constructed to assure positive contact between current-carrying parts.
2.4.1
Types of Terminal Blocks
2.4.1.1
Short-Circuiting Type
Short-circuiting type terminal blocks shall be furnished for all current
transformer secondary leads and shall have provision for shorting together
all leads from each current transformer without first opening any circuit.
Terminal blocks shall meet the requirements of paragraph CONTROL CIRCUIT
TERMINAL BLOCKS above.
2.4.1.2
Load Type
Load terminal blocks rated not less than 600 volts and of adequate capacity
shall be provided for the conductors for NEMA Size 3 and smaller motor
controllers and for other power circuits except those for feeder tap units.
The terminals shall be of either the stud type with contact nuts and
locking nuts or of the removable screw type, having length and space for at
least two indented terminals of the size required on the conductors to be
terminated. For conductors rated more than 50 amperes, screws shall have
hexagonal heads. Conducting parts between connected terminals shall have
adequate contact surface and cross-section to operate without overheating.
Each connected terminal shall have the circuit designation or wire number
placed on or near the terminal in permanent contrasting color.
2.4.2
Marking Strips
White or other light-colored plastic marking strips, fastened by screws to
each terminal block, shall be provided for wire designations. The wire
numbers shall be made with permanent ink. The marking strips shall be
reversible to permit marking both sides, or two marking strips shall be
furnished with each block. Marking strips shall accommodate the two sets
of wire numbers. Each device to which a connection is made shall be
assigned a device designation in accordance with NEMA ICS 1 and each device
terminal to which a connection is made shall be marked with a distinct
terminal marking corresponding to the wire designation used on the
Contractor's schematic and connection diagrams. The wire (terminal point)
designations used on the Contractor's wiring diagrams and printed on
SECTION 16403A
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