SECTION 16470
ENCLOSED CIRCUIT BREAKERS
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 enclosed
circuit breakers and/or molded case 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. The manufacturer shall furnish, but not be limited to the
following:
1.
Circuit breaker enclosure with dimensions and nameplate designation.
2.
Circuit breaker trip ratings and frame sizes.
3.
Conduit entry/exit locations.
4.
Assembly ratings, including short-circuit rating, voltage, and continuous
current rating.
5.
Cable terminal sizes.
6.
Product data.
16470-1
11/13
ENCLOSED CIRCUIT BREAKERS
1.04
SECTION 16470
DELIVERY, STORAGE AND HANDLING
A.
Deliver material and products in factory labeled packages. Store and handle in
strict compliance with manufacturer’s instructions and recommendations.
B.
Each unit shall be delivered in individual shipping cases and individually wrapped
for protection.
C.
Store in a clean, dry space. Maintain factory protection and /or provide an
additional heavy canvas or heavy plastic cover to protect equipment from dirt,
water, construction debris, and traffic. Where applicable, provide adequate
heating within enclosures to prevent condensation.
D.
Handle carefully to avoid damage to panelboards internal components,
enclosure and finish.
PART 2 - PRODUCTS
2.01
MANUFACTURERS
A.
2.02
2.03
The enclosed circuit breaker(s) shall be as manufactured by CUTLER-HAMMER,
GENERAL ELECTRIC, SIEMENS, or SQUARE D.
MATERIALS AND COMPONENTS
A.
Enclosed circuit breakers shall be furnished and installed by this Contractor as
shown on the Drawings. Enclosed circuit breakers shall be UL listed.
B.
Enclosed circuit breakers required and/or noted on the Drawings to be "four
wire" shall be furnished by the manufacturer complete with a solid neutral
assembly.
C.
Enclosed circuit breaker enclosures shall generally be NEMA 1 or NEMA 3R
(rainproof) for exterior locations, or where noted "WP" on the Drawings.
CIRCUIT BREAKERS
A.
Electrical circuits shall be protected by molded case circuit breakers as indicated
on the Drawings.
B.
The circuit breakers shall be operated by a toggle type handle and shall have a
quick-make, quick-break over-center switching mechanism that shall be
mechanically trip free from the handle so that the contacts cannot be held closed
against short circuits and abnormal currents. Tripping due to overload or short
circuit shall be clearly indicated by the handle automatically assuming a position
16470-2
11/13
ENCLOSED CIRCUIT BREAKERS
SECTION 16470
midway between the manual "ON" and "OFF" positions. All latch surfaces shall
be ground and polished. All poles of a multi-pole breaker shall be so constructed
that they open, close, and trip simultaneously.
C.
The circuit breakers shall be completely enclosed in a molded case. Noninterchangeable trip breakers shall have their covers sealed; interchangeable trip
breakers shall have the trip unit sealed to prevent tampering. Ampere ratings
shall be clearly visible. Contacts shall be non-welding silver alloy. Arc extinction
shall be accomplished by means of arc chutes consisting of metal grids mounted
in an insulating support. Breakers shall be of the bolt-on type; plug-in, plug-on,
blow-on, and clamp-on circuit breakers shall not be acceptable.
D.
Circuit breakers shall be 80% rated unless indicated on the Drawings to be 100%
rated.
E.
Circuit breakers shall have a minimum symmetrical interrupting capacity as
indicated on the Drawings. The interrupting ratings of the circuit breakers shall
be at least equal to, or greater than, the available short circuit at the line
terminals and not less than those values shown on the Drawings and specified in
this specification section or as determined by the Short-Circuit Coordination
Study whichever is higher. [ENGINEER, EDIT OUT SHORT-CKT STUDY IF
NOT IN PROJECT]
F.
Circuit breakers shall be listed with UL, conform to the applicable requirements
of the latest issue of NEMA Standards Publication No. AB1.
G.
Circuit breakers shall have thermal-magnetic trip units, with inverse time-current
characteristics, unless otherwise noted on the Drawings.
H.
1.
Automatic operation of all circuit breakers shall be obtained by means of
thermal-magnetic tripping devices located in each pole providing inverse
time delay and instantaneous circuit protection. Instantaneous pick-up
settings for each phase shall be adjustable on all frames 250A and
above.
2.
Circuit breakers shall be ambient compensating in that, as the ambient
temperature increases over 40° C, the circuit breaker automatically
derates itself to better protect its associated conductor.
3.
Circuit breakers 250A and above shall have thermal magnetic
interchangeable trip units.
Circuit breaker frames 400 ampere and above shall have microprocessor-based
RMS sensing trip units on 480 volt systems and on 208 volt systems where
indicated on the Drawings.
16470-3
11/13
ENCLOSED CIRCUIT BREAKERS
I.
SECTION 16470
1.
Solid State sensing shall measure true RMS current with capability to
st
measure through to the 21 harmonic. Automatic operation of all circuit
breakers shall be obtained by means of solid state tripping elements
providing inverse time delay and instantaneous and short-time circuit
protection. Continuous current rating shall be adjustable from 20% to
100% of trip unit rating. Long-time delay and instantaneous trip ratings
shall also be adjustable. The short time pick-up trip shall have
adjustable pick-up settings at definite times and with I2t delay.
2.
Long time current adjustment shall be possible without the need for a
rating plug.
3.
Where specifically indicated on the Drawings, enclosed circuit breakers
shall be provided with integral ground fault protection. Ground fault pickup shall be adjustable from 20% to 70% of the breakers maximum
continuous current rating, but in no case be greater than 1200A. Ground
fault time delay shall be adjustable with three (3) I2t delay settings.
4.
Solid State circuit breakers shall have built-in test ports for testing the
long-time delay, instantaneous, and ground fault functions (if equipped)
of the breaker by means of a test set.
5.
Provide one test set capable of testing all circuit breakers with a built-in
test port, unless previously provided under another section of these
specifications.
Circuit breaker accessories:
1.
Provide shunt-trips, bell alarms and auxiliary switches, etc. as may be
shown on the drawings. All accessories shall be UL Listed for field
installation.
2.
Coils for the shunt-trip circuit breakers associated with the elevator shutdown system, activated by the Fire Alarm and Detection System shall be
coordinated with the Fire Alarm and Detection System for the proper coil
voltage of the shunt-trip device.
J.
Circuit breakers shall be manufactured by the same manufacturer as the
panelboards and the circuit breaker enclosure and be factory installed.
K.
Lugs shall be rated for 75 degrees C terminations and shall bolt in place.
L.
Where indicated, circuit breakers shall be UL listed for series application.
(ENGINEER TO EDIT OUT THIS PARAGRAPH IF NOT USING SERIES
CONNECTED BREAKERS.)
16470-4
11/13
ENCLOSED CIRCUIT BREAKERS
2.04
MOLDED CASE SWITCHES
A.
2.05
SECTION 16470
Where indicated on the Drawings provide enclosed molded case switches.
Molded case switches shall employ the same operating mechanism as the
thermal magnetic and magnetic only circuit breaker units described above. The
molded case switch shall have a factory preset instantaneous function to allow
the switch to trip and protect itself at a high fault current, without thermal
overload protection.
NAMEPLATES
A.
Enclosed circuit breakers and or molded case 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.
PART 3 - EXECUTION
3.01
3.02
3.03
INSTALLATION
A.
The enclosed circuit breakers 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.
C.
Install units plumb, level and rigid without distortion to the units.
D.
Contractor shall install required safety labels.
FIELD TESTS
A.
Check tightness of all accessible mechanical and electrical connections to
assure they are torqued to the minimum acceptable manufacturer’s
recommendations.
B.
Check all enclosed circuit breakers and enclosures for proper grounding,
fastening and alignment.
FIELD ADJUSTMENTS
A.
This Contractor shall perform field adjustments of the protective devices as
required to place the equipment in final operating condition. Necessary field
settings of devices and adjustments and minor modifications to equipment shall
16470-5
11/13
ENCLOSED CIRCUIT BREAKERS
SECTION 16470
be carried out by this Contractor at no additional cost to the Owner.
B.
3.04
(ENGINEER, DELETE THIS PARAGRAPH WHEN SECTION 16015 “SHORTCIRCUIT/COORDINATION STUDY” IS NOT USED) The settings shall be in
accordance with the approved protective device coordination study or as directed
by the Engineer.
CLEANING
A.
Remove debris from enclosed circuit breaker enclosures and wipe dust and dirt
from all components.
B.
Repaint marred and scratched surfaces with touch-up paint to match original
finish.
END OF SECTION
16470-6
11/13