SECTION 16482
MOTOR CONTROL CENTERS (MCC)
PART 1 GENERAL
1.1 RELATED REQUIREMENTS
A. Applicable requirements of Division 0 and Division 1 shall govern work in this Section.
1.2 SCOPE
A. Provide motor control centers as indicated on the drawings and as specified herein.
1.3 QUALITY ASSURANCE
A. Requirements of Regulatory Agencies
1. National Fire Protection Association (NFPA). NFPA-70 - National Electrical Code (NEC), Occupational Safety and Health Administration (O.S.H.A.), and Wisconsin amendments thereto.
2. Underwriters' Laboratories, Inc. (UL). UL-845.
3. Local Codes and Ordinances.
B. Reference Standards. National Electrical Manufacturers Association (NEMA), NEMA ICS-2-322.
1.4 SHOP DRAWING SUBMITTALS
A. Opening size and layout in slab for MCC. Submit information prior to slab pour.
B. Project-specific elementary (control) diagrams.
C. Project-specific wiring and interconnection diagrams.
D. Submit detailed project specific control diagrams for each motor starter supplied. Refer to Division 11, 13 and 15 specifications, P&IDs and HVAC drawings for logic requirements.
E. Frontal elevation and dimension drawings. Elevation drawings to include front view of each MCC bucket/cubicle (switches, lights, operator’s, etc).
F. Bill of material listing all components.
G. Manufacturer's product data sheets.
H. Bucket nameplate information. Each bucket shall include nameplate(s) that consists of
a) equipment name (i.e. “BLOWER NO. 1")and b) equipment tag name. Refer to One- Line Diagram for source information.
PART 2 PRODUCTS
2.1 ACCEPTABLE MANUFACTURERS
A. Allen-Bradley
B. Cutler-Hammer/Eaton
C. Siemens
D. Square-D
2.2 MATERIAL AND EQUIPMENT
A. General.
1. Provide motor control centers where shown on drawings and as described by frontal elevation drawings, one-line diagrams, and equipment schedules.
B. Electrical ratings 1. 480 vac.
2. 3 ph, 4 wire (unless stated otherwise on plans). 3. 60 Hz.
4. 300 amp vertical bus minimum. 600 amp horizontal bus minimum.
5. 42,000 rms symmetrical amp bus bracing, minimum.
6. Unit IC ratings as shown on drawings.
C. Wiring.
1. NEMA Class II, Type B wiring.
2. Track mounted, pull apart terminals in unit.
D. Structure.
1. Motor control centers shall consist of one or more enclosed vertical sections 20 in. wide joined together to form a rigid, free standing assembly.
2. Sectionalize construction in 20 in. wide basic sections as the standard. Provide greater widths as required for the cubicle contents. Make provisions for future add-on of sections at either end.
3. Engraved MCC tag number identification nameplate.
a. Laminated plastic.
b. Letters 1/2 in. high.
c. White letters on black background.
d. On each MCC.
4. Provide six space factors per section. Exception: where permitted by manufacturer, provide feeder breaker in ½ size cubicles.
5. Prepaint treatment to resist corrosion. Baked enamel finish.
6. Removable one piece top plate. Open bottom for conduit entry.
E. Bus bars.
1. Tin plated copper.
2. Bus bar material completely plated.
3. Main lug compartment.
4. 600 amp minimum horizontal bus or as specified on drawings.
5. Glass reinforced alkyd bus insulators.
6. Plated vertical bus.
7. Bus joints made with bolts, self clinching nuts and Belleville washers.
8. Bus shall be front accessible.
F. Bus barriers.
1. Bus barrier opening at ½ space factor intervals for convenient pug-in.
2. Snap-in closing plates for unused openings.
3. Bottom covers over bus to prevent accidental contact with fish tapes are required.
G. Horizontal bus.
1. Continuous over length of MCC.
2. Minimum of 28% of main horizontal bus cross sectional area.
3. Locate in bottom of MCC.
H. Wireways.
1. Provide vertical wireway in each section.
2. Provide horizontal wireway, top and bottom, throughout entire length.
I. Motor Control Center Units.
1. Provide motor starters in Motor Control Centers as indicated in the One-Line Diagram and as specified in Section 16481 of the specifications.
2. The minimum size starter shall be Nema Size 1.
J. Compact disconnect switch.
1. Operator handle engaged with disconnect at all times.
2. Up and down hand motion.
3. Down as OFF.
4. Handle interlocked with unit door.
5. Handle pad-lockable in the open (off) position.
K. Doors.
1. Pan type ¼ turn latches or captive knurled thumb screws engaging with cage nuts.
2. Concealed hinges.
3. Padlock provision to lock unit with plugs disengaged from bus.
4. Unit supported and guided by unit support pan.
5. Pan easily relocated without tools.
6. Unit identification tag fastened to unit saddle.
7. Unit compartments enclosed and isolated from adjacent units, busses and wireways except for openings for conductors entrance into units.
L. Branch circuit breakers.
1. Unless otherwise indicated on the One-Line Diagram(s), provide thermal- magnetic type circuit breakers.
M. Main circuit breakers
1. To enable coordination, provide main circuit breakers with the following features:
A. Long-time and instantaneous trip protection
B. Long-time pickup and delay adjustment
C. Short-time pickup and delay adjustment
D. Ground fault pickup and delay adjustment
E. U.L. Listed short-circuit rating of 42,000RMS (minimum)
F. MICROLOGIC trip circuit breakers, or approved equal
N. Additional cubical contents.
1. Each door of a cubical containing a motor starter shall include a heavy-duty LED oil-tight green “running” and red “fail” light. Contractor to confirm colors with owner if project is renovation to or expansion of an existing facility.
2. Each section shall provide all internal control logic circuitry per the requirements of Division 11, 13 and 15 specifications, P&IDs and or HVAC drawings.
3. Each section shall provide the following interface signals, prewired to terminal blocks for connections to field mounted devices:
a. Input connections for field mounted HOA switches
b. Input connections for all other devices shown on P&IDs.
4. Each section shall provide the following interface signals, prewired to terminal block for field connections to SCADA system:
a. Remote START COMMAND input. (maintained or momentary as shown on P&IDs.)
b. Remote TRIP COMMAND input. (As shown on P&IDs.)
c. Controller RESET input
d. Controller RUN output.
e. Controller LOCAL/REMOTE output
f. Controller OVERLOAD FAIL output.
g. All other signal interfaces as shown on the P&IDs.
5. Each door to include a heavy-duty oil-tight hand-off-auto selector switch, if indicated on project P&IDs.
6. Each door of a cubical containing a motor starter shall include a heavy-duty oil- tight Reset pushbutton.
7. Each door of a cubical containing an ASC shall include the HMI keypad.
8. Each section of an MCC located in an unheated space shall include properly sized space heater(s) and associated wiring and fuses.
O. ARC FLASH WARNING LABELS
1. All motor control centers shall include a warning label indicating the risk of arc flash. The warning label shall comply with N.E.C. article 110.16 and O.S.H.A. 29.
PART 3 EXECUTION
3.1 INSPECTION
A. Examine the areas and conditions under which motor control centers are to be installed and notify Engineer in writing of conditions detrimental to proper and timely completion of work.
B. Do not proceed with work until unsatisfactory conditions have been corrected.
3.2 INSTALLATION
A. Install and wire where shown in accordance with NEC, manufacturer's written instructions, and with recognized industry practices to ensure that they comply with requirements and serve intended purposes.
B. Install on 4 in. concrete housekeeping pad. Coordinate size and location with General Contractor.
C. Secure to concrete pad with steel bolts.
D. Tighten bus connections and mechanical fasteners.
E. Touch up scratched or marred surfaces to match original finish.
F. Close openings in floor and concrete pad with concrete or other approved fire rated materials.
3.3 ADJUSTMENT AND CLEANING
A. Clean MCC equipment and enclosures of dirt and debris.
3.4 PRODUCT DELIVERY, STORAGE AND HANDLING
A. Handle equipment carefully to prevent internal components damage, breakage and denting and scoring the enclosure finish. Do not install damaged equipment.
B. Store equipment in a clean, dry space and protect from dirt, fumes, water, construction debris and physical damage.
C. After installation, protect from damage by work of other trades.
END OF SECTION
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