SECTION 16440
DISCONNECT SWITCHES
PART 1 - GENERAL
1.01
REQUIREMENTS
A.
1.02
SCOPE
A.
1.03
The general provisions of the Contract, including General and Supplementary
Conditions and General Requirements, apply to the work specified in this
Section.
The work under this Section shall include furnishing and installing safety
switches and/or bolted pressure switches as shown on the Drawings and herein
specified.
QUALITY ASSURANCE
A.
All equipment, materials, and their installation shall conform to the requirements
of the National Electrical Code (NEC), local code requirements, and these
Specifications.
B.
All equipment and materials shall be listed by Underwriter's Laboratories, Inc.
(UL) for their intended use and shall bear the UL label.
C.
Equipment shall be constructed in accordance with National Electrical
Manufacturer's Association (NEMA) standards.
D.
Submittals are required in accordance with SECTION 16010 of these
Specifications.
PART 2 - PRODUCTS
2.01
SAFETY SWITCHES
A.
This Contractor shall furnish and install where shown on the Drawings, heavyduty type safety switches. Safety switches shall be NEMA heavy-duty type HD
only and shall be UL listed.
The heavy-duty safety switches shall be
manufactured by CUTLER-HAMMER, GENERAL ELECTRIC, SIEMENS, or
SQUARE D.
B.
Switches shall have a quick-make and quick-break operating handle and
mechanism that shall be an integral part of the enclosure. Switches shall be
horsepower rated 250 volt for 120/208 volt systems or 600 volt for 277/480 volt
system. The lugs shall be UL listed for copper conductors and be front
16440-1
11/13
DISCONNECT SWITCHES
SECTION 16440
removable. Ampere ratings shall be as indicated on the Drawings.
2.02
C.
Safety switches required and/or noted on the Drawings to be "four wire" shall be
furnished by the manufacturer complete with a solid neutral assembly.
D.
Safety switches shall have defectable door interlocks that prevent the door from
opening when the handle is in the “ON” position. Defeater mechanism shall be
front accessible.
E.
Enclosures for the switches shall generally be NEMA 1 or NEMA 3R (rainproof)
for exterior locations, or where noted "WP" on the Drawings.
BOLTED PRESSURE SWITCHES
A.
This Contractor shall furnish and install where shown on the Drawings, true
bolted contact load-break type switches with provisions for NEMA Class L fuses
(fuses shall be furnished and installed by this Contractor). The stored energy
deadfront operating mechanism shall include disk springs, compressed and
released by the operating handle, to provide quick-positive switching action
independent of the speed with which it is operated. The mechanism shall be
designed so that the switch can be closed only after the opening spring has been
charged, ready for manual opening by mechanical pushbutton.
B.
The switch operating handle shall be mechanically interlocked with the fuse
access door and have provisions for padlocking in OPEN position.
C.
The switch shall have an interrupting rating of twelve (12) times the continuous
rating and capable of carrying 100% of rated current and shall have been tested
in accordance with UL Subject 977. The switch shall be suitable for use on
circuits having available fault currents of 65,000 RMS symmetrical amperes
rated (250) (600) VAC and of the ampacity shown on the Drawings. Highpressure contact switches do not meet the intent of these specifications.
D.
The switch shall be complete with single phase protection to open the main
device upon loss of any single phase but not upon simultaneous loss of all three
(3) phases.
E.
The switch shall be complete with separate blown fuse protection to open the
bolted pressure switch if one or more of the Class L fuses operate. Indicating
lights mounted on the front of the switch shall be included as a means of
showing that the fuses have operated. Operating lights shall operate only when a
fuse has blown.
F.
The switch shall have two (2) sets of auxillary contacts (2 normally open and 2
normally closed) for switch position monitoring.
16440-2
11/13
DISCONNECT SWITCHES
G.
SECTION 16440
A ground fault protection system shall be included for the bolted pressure switch
as shown on the Drawings or as required by NEC.
1.
The system shall consist of a current sensor enclosing all phase and
neutral conductors of the circuit to be monitored, and appropriate relaying
equipment to provide the desired ground fault current sensitivity and timecurrent response characteristics. The switch shall be equipped to
function in conjunction with the other elements of the ground fault
protection system. Installation of the equipment shall be in all respects in
accordance with the manufacturer's recommendations.
2.
A current sensor shall be provided of the size necessary to encircle the
phase conductors and the neutral conductor of the circuit to be
monitored. Current sensor output shall be coordinated with the required
input to the relay. A test winding shall be included to simulate the flow of
ground fault current through the current sensor in order to test the
operation of the ground fault protection system including sensor pick-up
relay, and circuit protective device operation. The frame of the current
sensor shall be so constructed that one leg can be opened to allow
removal of installation around cable or bus without disturbing the cable or
requiring drop-links in the bus.
3.
The ground fault relay shall be of solid state construction, except that a
coil operated output relay shall be provided to control 120 volt power to
operate the associated fusible bolted pressure switch ground fault trip
mechanism. The relay shall require 120 volt power to operate the
associated main device. Adjustable pickup current sensitivity for ground
currents from 200 amperes to 1200 amperes shall be provided. A
calibrated dial shall be provided for setting the current pickup point in the
field. Settings for individual relays shall be 1200 amperes or as
determined by the Short-Circuit Coordination Study whichever is
lower. Time delay provided by the relay circuitry shall be nominally 0.2
seconds or as determined by the Short-Circuit Coordination Study
and shall be permanently calibrated. A self-contained test circuit utilizing
the test coil provided in the current sensor shall be incorporated in the
system. The test circuit shall be part of the monitor panel that shall be
mounted on the front cover of the switch. [ENGINEER, EDIT OUT
SHORT-CIRCUIT STUDY PORTIONS IF NOT IN PROJECT]
H.
The switch enclosure shall be NEMA 1, floor or wall mounted as shown on the
Drawings.
I.
The switch shall be manufactured by PRINGLE and shall be type CBC or
approved equal.
16440-3
11/13
DISCONNECT SWITCHES
2.03
SECTION 16440
NAMEPLATE
A.
Disconnect switches, including exterior locations, shall have nameplates of 1/16
inch thick laminated plastic with 3/16 inch high white letters on a black
background. Nameplates shall identify each piece of equipment and shall be
mounted on the front top of the enclosure. Nameplates shall be screw fastened
using stainless steel screws.
B.
Disconnect switches for elevator equipment shall also provide nameplates and
signage to identify the location of the supply side overcurrent protective device,
including circuit numbers, per NEC Article 620. Nameplates and signage shall
be laminated plastic as hereinbefore described.
PART 3 - EXECUTION
3.01
INSTALLATION
A.
The disconnect switches shall be securely mounted in accordance with the NEC,
approximately forty eight (48) inches but no less than twelve (12) inches above
the finished floor to the bottom unless otherwise noted.
B.
Mounting brackets and hardware exposed to weather shall be galvanized or
otherwise suitably protected from corrosion.
1.
All NEMA 3R disconnect safety switches mounting openings not used
must be permanently sealed to keep rain, moisture, insects, etc. from
entering the switch housing. The use of stainless steel screws/nuts with
rubber washers and silicone sealant may be used, or another approved
method for a completely sealed switch housing.
C.
The fuses (type and size as noted on the Drawings) as specified shall be
installed in disconnect switches requiring fuses. Rejection fuse clips shall be
installed where called for on the Drawings or in these Specifications.
D.
Contractor shall install required safety labels.
END OF SECTION
16440-4
11/13