ENGINEERING SPECIFICATION FOR

ENGINEERING SPECIFICATION FOR LOW VOLTAGE AC MOTOR CONTROL CENTERS TABLE OF CONTENTS 1.0 SCOPE 2.0 CODES AND STANDARDS 3.0 CONSTRUCTION 4.0 INSPECTION AND TESTING SCOPE This specification covers the general requirements for Low Voltage AC Motor Control Centers (MCCs). The specific requirements are given on the Data Sheet(s) and the One-Line Diagram(s) or MCC Tabulations. Design, fabricate, test, and deliver (when required by release) motor control centers (MCCs) and accessories in accordance with this specification. CODES AND STANDARDS All MCC assemblies shall be designed, manufactured and tested in accordance with the applicable sections of the latest edition of the following standards: Applicable Local and National Codes, Regulations and Standards NEMA ICS 1 General Requirements NEMA ICS 2 Controllers, Contactors, and Overload Relays Rated not more than 2000 Volts ac or 750 Volts dc NEMA ICS 6 Enclosures NEMA ICS 18 Motor Control Centers NESC National Electrical Safety Code NFPA 70 National Electrical Code (NEC) OSHA Occupational Safety & Health Administration UL 489 Molded Case Circuit Breakers, Molded Case Switches and Circuit Breaker Enclosures UL 845 Motor Control Centers (including Attachment A) For the purposes of this specification, the word "should" shall be replaced with the word "shall" wherever it appears in the above referenced standards. Except for special units produced to meet the requirements of the material requisition, all electrical equipment and components shall be listed by a Nationally Recognized Testing Laboratory (NRTL) and shall carry a label (e.g., UL, CSA). Any conflicts between the referenced documents shall be identified to the Buyer in writing for resolution. In general, when resolving conflicts, the following order of precedence shall apply: One Line Diagram(s) MCC Tabulation(s) Data Sheet(s) Purchase Order This Specification Referenced Standards CONSTRUCTION General Construction Features MCC assemblies shall have NEMA Class I, Type B wiring unless otherwise specified on the Data Sheet(s) or the supplier software tool report. The wiring for controllers smaller than Size 4 shall be NEMA Class I, Type B-T. All equipment shall be fully rated for symmetrical fault currents equal to or greater than the bus bracing specified on the Data Sheet(s) or the supplier software tool report. The MCC enclosures shall be designed for indoor installation unless otherwise specified on the Data Sheet(s) or the supplier software tool report. When outdoor installations are specified, the following shall apply: Walk-through weatherproof housing shall be provided with lockable access doors at both ends Lockable access doors shall be equipped with stops Walk-in aisle doors shall be equipped with panic bars that over-ride door locks. Walk-in aisle and all other normal operation and maintenance areas shall be provided with guarded fluorescent lighting for a minimum maintained lighting level of 500 lux on the floor. A light switch for interior lights shall be provided adjacent to each exterior walk-in aisle door. A photo-cell controlled 70 W HPS exterior light shall be provided at each exterior walk-in aisle door. Guarded 120V space heaters shall be provided to preclude formation of condensation on operating parts. The housing interior shall be provided with a NEMA 5-20R receptacles within 25 feet of any point within the housing. All convenience receptacles shall be ground fault interrupter (GFCI) type or be supplied from GFCI breakers. All auxiliary lights, receptacles, vent fans and space heaters shall be on separate independent circuits. Front only MCCs shall be suitable for back-to-wall or back-to-back installation with no rear access required. Combination control units (Size 4 and smaller), and feeder units (225 A and smaller) shall be plug-in type. If it is the manufacturer’s standard, Size 5 combination control units and 400 ampere frame feeder units may be plug-in. Units of the same size and type shall be fully interchangeable where control and power circuitry permit. Provide units with positive grounding means to ground the frame before the stabs engage the bus. Individual controller units and/or feeder units shall be isolated and baffled from all other units, adjacent buses and wireways. Design motor control centers so that power and control cables for the feeder devices can enter at both the top and bottom. The incoming feeder entry shall be designated on the Data Sheet(s) or supplier software. Each vertical section shall have an isolated vertical wireway with a separate, full height, hinged door and captive hardware, except for oversized units (e.g., incoming units). Provide vertical sections with two isolated horizontal wireways, one at the top and one at the bottom, readily accessible by removal of the cover plates. The wireway shall form a convenient wiring space the entire width of the control center. Lugs for incoming line and outgoing feeders larger than #4/0 AWG shall be positioned so that the lug openings are oriented toward the cable or conduit entrances, with an 18-inch minimum space between the lugs and the cable entrance. Each MCC shall be provided with facilities for lifting, and the base construction shall be capable of rolling or skidding without damage. When specified on the Data Sheet(s) or the supplier software tool report, provide removable means for lifting from top. Each MCC shall be capable of the addition of future vertical sections at either end of the line-up. The bus shall be drilled, and removable cover plates shall be furnished on the end vertical sections. Future spaces shall be provided with vertical bus, door, guide rails and other hardware required to permit future addition of combination controller, and/or feeder unit without de-energizing the motor control center. Provide removable top plates suitable for drilling for top entry of cables, unless an extension box with a full drip shield is supplied, in which case top plates are omitted. Enclosures shall not have sharp edges or pointed objects, such as the pointed ends of sheet metal screws, on the exterior, inside any wireway, or in any access space required for installation, operation, or maintenance. Adhesives shall not be used for mounting any devices, parts, or components. All devices, parts and components including nameplates, wireways, and wire supports shall be mounted with screws or bolts. Bus Requirements The main power bus shall be copper with tin-plated joints unless otherwise specified on the Data Sheet(s). The bus rating of the incoming section shall be the same as the main power bus. The vertical bus extensions shall be copper with tin-plated joints, and shall be rated for 300 A minimum, unless otherwise specified on the Data Sheet(s). All unused openings for unit bus stabs shall be furnished with insulating covers. A continuous 1/4 inch by 2 inch minimum copper ground bus shall be provided throughout the entire length of the assembly and located as specified on the Data Sheet(s). Each end of the ground bus shall be provided with two holes drilled to accommodate NEMA lugs for connections of 4/0 AWG grounding cables. Bus phasing shall be arranged A-B-C, left to right, top to bottom, front to back, when viewed from the front. Provide a neutral bus when specified on the Data Sheet(s) or the supplier software tool report. The neutral bus shall be copper and shall be provided throughout the entire length of the assembly or otherwise as indicated on the Data Sheet(s) or supplier software tool report. The neutral bus shall be bonded to the ground bus with removable jumpers. Combination Control Units Combination motor control units shall consist of a line side disconnect with overcurrent protection and a magnetic contactor, with three-phase overload protection for motor controllers. Each combination control unit compartment shall be provided with an externally operable circuit disconnect means and a door mounted manual reset button for overload elements. Provide for padlocking the starter units in the OFF position. The minimum contactor size shall be NEMA Size 1. Vacuum contactors for Size 4 and larger controllers shall be provided if indicated in the Data Sheet(s). Controllers shall be capable of "holding in" for voltage dips to 70 percent of nominal bus voltage. Seller shall define maximum one-way distances for the contactor coil control circuit and required modifications for longer control circuit distances. Provide a 120 Vac interposing relay for all NEMA size 1 and 2 contactor coils whose inrush current exceeds 3 amperes. All Size 5 controllers shall be provided with a 120-Vac interposing relay, and a contactor coil operating at line voltage. Each controller shall be provided with two spare normally open (NO) and two spare normally closed (NC) auxiliary dry contacts, wired to the terminal block, unless otherwise specified on the Data Sheet(s). Unless otherwise specified on the Data Sheet, each controller shall be provided with an individual control power transformer (CPT). The CPT’s shall be provided with two primary fuses and one secondary fuse. The non-fused leg of the secondary of the transformer shall be grounded. The CPT’s secondary voltage shall be 120 V or as specified in the Data Sheet. The minimum CPT size shall be 100 VA. NEMA size 1 and 2 controllers shall be provided with a CPT rated at least 50 VA above the manufacturer's standard CPT. Each controller shall be wired for provision of remote control operation and or communication with the Buyer’s communication network as noted in the Data Sheets. Feeder Units Feeder units shall either be circuit breakers or fusible switches as indicated in the Data Sheet(s). The feeder units shall have an interrupting rating that meets or exceeds the available short circuit indicated in the Data Sheet(s) and/or the supplier software tool reports. Each feeder unit compartment shall be provided with an externally operable circuit disconnect means. Provide for padlocking the feeder units in the OFF position. Manually operated, trip free, molded case, 3-pole breakers shall be in accordance with UL 489 and shall be equipped with thermal-magnetic overcurrent protection having continuous current rating on each pole. Equip breakers with an external operating mechanism to allow operation from the front only with the unit door closed. The operating mechanism shall clearly indicate whether breaker is ON, OFF, or TRIPPED. Fusible feeder switches shall be quick-make, quick-break gang-operated type. Provide wiring between the bus stab and the line side of the feeder unit rated in accordance with the frame size. Ground Fault Devices When specified on the Data Sheet(s) or the supplier software tool report ground fault sensors and relays (50 GS) are required as an accessory for combination control unit sizes 3 and larger and feeder breaker units with a trip size greater than 50 A. Include with the associated breaker a 120V shunt trip coil and size the control power transformer adequately to shunt trip the breaker. Consider the burden of the shunt trip coil as being in addition to all other burdens imposed upon the control transformer. Transformer Units When specified on the Data Sheet(s) or the supplier software tool report provide dry-type power transformers with Class 220 insulation and 80oC temperature rise. Provide overcurrent protection in accordance with NFPA 70 and UL 845. Panelboard Units When specified on the Data Sheet(s) or the supplier software tool report, provide panelboard units that meet the requirements of NEMA Standard PB-1 and UL Standard 67. Include molded case, thermal-magnetic circuit breakers having a continuous current rating as shown on the one-lines or MCC tabulations and/or the supplier software tool reports Circuit breakers shall meet UL 489 requirements. Indicating Lights All indicating lights shall be LED type unless otherwise specified on the Data Sheet(s). Space Heaters When specified on the Data Sheet(s), space heaters shall be provided in each vertical section sized to provide the heat output required to prevent condensation when operated on a 120 volt system and located so as not to interfere with wireways. All space heaters shall be controlled by a single thermostat and furnished with a single pole circuit breaker for the supply disconnect. The space heater circuit shall be wired to an accessible terminal block in the incoming section for connection of external power wiring. The associated motor starter shall control motor space heater. When it is specified that motor space heaters are to be fed from an external source, a normally closed (NC) contact from the starter shall be wired out to terminal blocks for control. Two adjacent terminal points (4 total) shall be provided for connection of the external power wiring. Wiring And Terminations All power and control wiring shall be flame-retardant; moisture, heat and oil-resistant 600 V stranded copper. Power wiring shall be #12 AWG minimum. Control wiring shall be the manufacturer’s standard size. Power wiring shall be color coded. All wiring shall be continuous from terminal to terminal without splices and tagged at both ends with plastic sleeve-type wire markers. Wire numbers shall match the Seller's interconnection drawing. All control wiring in each motor control and/or breaker unit shall be wired to two piece "pull apart" type terminal blocks. A minimum of 20 percent spare terminals shall be provided for NEMA size 3 compartments and larger. The maximum number of spare terminal blocks shall be provided that a NEMA size 1 or 2 compartment can accommodate. Wiring for current transformer (CT) secondary leads shall be crimped in self-insulated compression ring-type lugs, and terminated on shorting screw-type terminal blocks. Minimum CT conductor size shall be #10 AWG. Seller's wiring shall be connected to only one side of all terminal blocks and no more than two wires per terminal shall be permitted. All field cable terminals shall be rated for use with 75oC, stranded, copper conductors. Terminal blocks shall be supplied and clearly marked for wiring that will be installed by the Buyer, including wiring between shipping sections. All incoming line and ground conductor terminal lugs shall be provided by the Seller, and shall be NEMA two hole long barrel compression type with cast bodies. Nameplates Each MCC vertical section, individual control unit, and/or feeder unit shall be identified with nameplates. Nameplates shall be machine engraved lamicoid plastic, with black lettering on a white background. A red nameplate with 1/4 inch high white letters shall be attached to the door of each compartment where wiring fed from an external power source is accessible. The nameplate shall read as follows: DANGER - EXTERNAL VOLTAGE SOURCE Lettering for the overall MCC assembly shall be 1 inch high. Lettering for vertical sections shall be 1/2 inch high. Lettering for the individual control and/or breaker units shall be 3/16 inch high. Nameplate information will be provided by the Buyer. Painting The color of the MCC enclosures is specified in the Data Sheet(s). Clean and finish paint in accordance with manufacturer's standard procedure. The Seller shall supply two 1-pint cans of paint for field touch-up for each motor control center provided. INSPECTION AND TESTING In addition to the NEMA standard routine tests, the following tests shall be performed on each MCC, unless otherwise specified on the Data Sheet(s): Hi-Pot test of all buses Continuity check of all wiring, and check for conformance to drawings. Complete functional test of all apparatus and equipment. Perform dielectric test The Seller shall notify the Buyer two weeks prior to when tests are to be performed. The Buyer or his representative reserves the right to inspect the equipment and/or witness the tests at the factory. PAGE PAGE 9 OF NUMPAGES 9 PAGE PAGE 1 OF NUMPAGES 9