DESIGN AND CONSTRUCTION STANDARDS SPECIFICATION GUIDELINES

Transcription

1 SECTION ELECTRICAL DISTRIBUTION CONCRETE ENCASED PRIMARY DUCTBANK SYSTEMS Duct Banks shall be installed by qualified electrical contractors. Provide type EB PVC 5 inch duct equal to Carlon #68716 and EB PVC 2 inch duct equal to Carlon # Terminate duct with end bells equivalent to OZ/Gedney Type TNS. After the trench is excavated and properly graded a concrete base shall be installed. The concrete base shall be a minimum of 4 inches thick with rebar reinforcement. Included in the base shall be rebar that shall be used for the purpose of tying down the PVC conduits thus preventing any floating of the duct sections when the concrete is installed. Electrical ducts shall be installed by an electrical contractor. Steel conduits are required as follows: Out of all manholes and buildings for a distance of approximately 10 feet, or as shown on the plans. At all construction joints if concrete pours are interrupted. Under all surfaces used for motor vehicle travel. With these exceptions, the raceway system shall consist of Poly-vinyl-chloride(PVC) ducts in sections as noted on the drawings. All sections shall be encased with concrete. PVC shall equal Carlon Type EB, 5 inches = 5.56 inches O.D., and minimum wall.125 inch and 2 inches = 2.37 inches O.D. and minimum wall.06 inch. Base and intermediate spacers shall be Carlon catalog #S288PL and S289PL or equivalent. Spacers shall be provided on maximum 5 foot centers and closer where required. Ducts shall be furnished in minimum 10 foot lengths. Use compound on all duct and conduit couplings. All duct and conduit couplings shall be watertight. After ducts are installed, they shall be tied down to prevent floating. Ties shall consist of reinforcing rods only and must conform to details shown on drawings. All mud and debris shall be removed from ducts, conduits, spacers, etc., before concrete is poured. Tape steel conduit couplings only. Duct run must pitch a minimum of 6 inches per 100 feet. Use large sweeps in primary ducts and conduits where primary lines are not straight. All duct shall be installed in such a manner to prevent accumulation of water. All conduits shall terminate 2 inches inside walls with end bells in all primary manholes. All conduits shall be evenly spaced and aligned with each other. Install #10 solid copper fish line in all ducts and conduits. It is the intent that each section of line (from manhole to manhole or from manhole to building) shall be poured complete in one operation. No construction joints shall be permitted between manholes. In case unusual conditions require a construction joint, furnish and install steel conduit for a minimum of 5 feet on either side of the joint. Concrete shall be poured at construction joints per the details indicated on the drawings. The top of the concrete encasement shall be a minimum of 24 inches below final grade. In special cases, this requirement shall be waived where field conditions require. However, such conditions must be approved by the Construction Manager and University Utilities and shall be considered the last resort in correcting the situation. CONCRETE Concrete shall cover the duct a minimum of 3 in all directions, and a maximum of 6. UPDATED - JULY 23, 2009 Page 1 of 10

2 Concrete shall be 4,000 psi and shall have the color additive Colorcron - Tile Red as manufactured by Masterbuilders, Solomon Grind Chemical Services #140 Red, or approved equal. The color additive shall have a minimum concentration of 9 lbs. per bag of cement and shall be mixed throughout all of the duct bank concrete. Maximum aggregate size shall be 3/4. Concrete shall NOT be placed with the aid of a mechanical vibrator. If trench erosion occurs, use of forms may be required to prevent overly large masses of concrete. A red warning tape that is a minimum of 6 wide shall be installed 18 above all duct banks. There shall be a minimum of 3 inches of homogeneous, waterproof concrete around all ducts and conduits. Encasement shall be poured complete and continuous from one manhole to another and from manholes to buildings. Minimum reinforcing of the concrete shall be #4. Reinforcing shall be installed longitudinally, at each corner of the duct (in cross section) and along the top, bottom, and sides at a maximum of 6 on center. All reinforcing steel shall have a minimum concrete cover of 1½. Reinforcing shall be installed latitudinal, as needed to hold the above in place during placement of the concrete. After duct encasement is placed, and before backfill is installed, pull a mandrel through the ducts 1/4 inch in diameter less than the ducts. If this test indicates that there are obstructions or water in the duct system, that section of the system shall be removed and a new section installed at no additional cost to the University. Duct bank penetrations into manholes shall continue completely through the wall of the manhole and shall use one larger hole rather than several small holes. If above method is not practical, the concrete may stop outside the manhole but must be pinned to the manhole with steel pins to prevent differential settlement. All unused duct shall have a nylon or polypropylene pull string installed for future use. The pull string shall be Greenlee or equal with a minimum of 240 lbs. tensile strength, and shall be rot and mildew resistant. Wire shall not be used. Duct bank penetrations of foundation wall shall comply with the following: Concrete encased duct banks shall terminate at the exterior surface of the foundation wall. The conduit shall make individual penetrations of the foundation wall. All duct banks shall be attached to the foundation wall in one of two manners. In new construction, the reinforcing steel of the foundation wall may be extended into the concrete encasement of the duct bank at the time of placement. Alternately, reinforcing steel may be drilled into the foundation wall and extended into the duct bank concrete. The steel that is inserted into the foundation wall shall be attached through the use of epoxy capsules, similar to those supplied by Hilti. All duct bank conduit within 8 of the foundation wall penetration shall be rigid steel conduit. The conduit shall be installed with a grade away from the building. The conduit shall penetrate the foundation wall in the following manner: For new construction, the foundation wall shall have a steel sleeve installed that is 2 larger in diameter than the conduit to be installed. For existing construction, the hole shall be core drilled. In multiple duct situations, sufficient space shall remain between the penetrations to maintain the structural integrity of the foundation wall. A rubber seal, equal to Link-Seal, shall be installed in the space between the conduit and the sleeve or drilled hole, near the interior surface of the foundation wall. The same space shall have waterproofing installed on the exterior side of the rubber seal. MEDIUM VOLTAGE (601 volts - 69,000 volts) UPDATED - JULY 23, 2009 Page 2 of 10

3 Medium voltage cables shall be furnished and installed by the University. Medium voltage switch gear and primary transformers shall be furnished and installed by the University Facilities department. PACKAGED GENERATOR ASSEMBLIES Generator Fire Safety: Generator assemblies should be located outside the building when possible. If generators have to be located indoors, they shall be located in three (3) hour cutoff rooms provided with doorway curbing and emergency drainage. Generator room fuel day tanks shall be at most 660 gallon, provided with spill containment and leak detection. All fuel piping shall exit the top of the tank. All fuel piping from the outside of the building for day tank filling and venting shall be hard piped. A high liquid level device shall be provided for day tank overflow protection. A generator fuel system shall be arranged to automatically shut down upon a fire, detected leak or high day tank level. All generators 750 KW and larger require a Utility grade relay package. Consult with Facilities Management- Environmental Services for information on generator operating permits and Spill Prevention Control and Countermeasures (SPCC). All generator sets shall be located to disperse exhaust fumes, vibration and noise without affecting the normal functions of the building and surrounding site. On-site fuel source shall provide for a minimum of 8 hours of run time. Generator type and fuel type shall be evaluated on an individual project basis. All generators shall have a closed transition transfer switch. Provide startup services and training for Owner s personnel by a factory certified service representative. Minimum training time shall be 4 hours. Acceptable Manufacturers - Any manufacturer with a service center within a 100 mile radius of the University of South Alabama is acceptable. Generator assemblies should be located outside the building. If generators must be located indoors, they should be located in three hour cutoff rooms provided with doorway curbing and emergency drainage. Generator room fuel day tanks should be at most 660 gallon, provided with spill containment and leak detection. All fuel piping should exist the top of the tank. All fuel piping from the outside of the building for day tank filling and venting should be hard piped. A high liquid level device should be provided for day tank overflow protection. The generator fuel system should be arranged to automatically shut down upon a fire, detected leak or high day tank level. Battery Equipment Sealed batteries shall be used for emergency lighting systems when an emergency generator is not available. UPDATED - JULY 23, 2009 Page 3 of 10

4 Provide adequate ventilation and cooling of battery rooms and battery cabinets to maintain full life expectancy. Batteries on racks or in cabinets shall be accessible for maintenance. Vertical access above batteries shall be a minimum of 6 inches. Transfer Switches All transfer switches shall be the closed transition type. Provide a minimum of two sets of auxiliary form C contacts for normal and emergency transfer switch positions. Transient Voltage Suppression Some users may require transient voltage surge suppression. The Design Professional shall review options with the user to determine specific needs. When suppression equipment protects an entire panelboard, locate this equipment inside the panelboard enclosure. Provide a disconnecting means to isolate the suppression equipment for repair and replacement. Low Voltage Conductors Aluminum conductors are prohibited. The minimum wire size for lighting and power branch circuits is #12 AWG. The minimum wire size for Class 1 control circuits is #14 AWG. Any conductors installed in flexible conduit at terminal connections of rotating, vibrating or moveable equipment shall be of stranded wire. Normal, emergency, life safety, 120/208, and 277/480 shall not occupy the same raceways. Exception: normal and emergency conductors of the same voltage in G4000 wiremold. Neutral conductor capacity shall be increased as necessary for harmonics. Grounding and Bonding for Electrical Systems All grounding system conductors shall be copper. Provide a grounding conductor with all circuits. SECONDARY CIRCUITS Secondary service protector switchgear will be furnished and installed by the University Facilities department in conjunction with the contractor. Color code secondary service, feeder, and branch circuit conductors with factory applied color as follows: 208/120 Volts Phase 480/277 Volts Black A Brown Red B Orange Blue C Yellow White Neutral White or Gray Green Ground Green UPDATED - JULY 23, 2009 Page 4 of 10

5 Service Entrance At the points where conduit penetrates concrete that is in contact with soil, that conduit shall be Schedule 80 PVC conduit bedded in sand. If the PVC is a bend of greater than 45 degrees, the bend shall be completely encased in concrete. Switchboards Phase, neutral and ground bus shall be copper. The phase arrangement on three phase bus shall be A-B-C from left to right, top to bottom, front to back as viewed from the front of the switchboard. Provide a minimum 20% spare, usable space in new switchboards for future increases in electrical requirements. Provide continuous ground bus the full length of the switchboard. In existing buildings, new switchboards shall match existing switchboards. Acceptable Manufacturers Square D General Electric Cutler-Hammer Panelboards Provide 5 spare conduit stubs from flush panels into suspended ceiling space or other accessible space. Provide a minimum 20% spare circuit space in new panelboards. Phase, neutral and ground bus shall be copper. All panelboards shall have separate neutral and grounding busses. All grounding and neutral wiring shall be terminated on the proper bus. In existing buildings, new panelboards shall match existing panelboards. Provide each panel with a clear, plastic covered, typed circuit schedule. The schedule shall identify circuits by room number and location in room using final room numbers provided by the Owner. Provide a label on the inside of the panelboard door with panel ID and power origin. Circuit breakers on branch circuit panelboards shall be bolt-on type. Covers to consist of full-length hinge. (Door within a door) Acceptable Manufacturers Square D General Electric Cutler-Hammer MOTOR CONTROL CENTERS Starters shall have fusible disconnects rather than circuit breakers. Control circuit voltage shall be 120 volts or less. Provide a minimum of two auxiliary contacts (1 N.O. and 1 N.C.) in magnetic starters in addition to what is being used. UPDATED - JULY 23, 2009 Page 5 of 10

6 Design each motor control center section so starter units may be rearranged, removed or added. Provide a minimum 20% spare, usable space in each new motor control center. In existing buildings, new motor control centers shall match existing motor control centers. Acceptable Manufacturers Square D General Electric Cutler-Hammer ELECTRICITY METERING Locate low voltage watt-hour metering (e.g. sidewalk, parking lot, and roadway lighting) near the primary building metering or provide a raceway (3/4 in. conduit minimum) from the low voltage meter to the primary metering location. Place a disconnecting means ahead of any low voltage watt-hour meter. All contactors shall be on the load side of low voltage watt-hour meters. Line voltage must be connected to the line side of low voltage watt-hour meters at all times for the display to function and shall not be tied to building control systems. FUSES Renewable fuses shall not be used. As much as possible, equipment should be specified with fuse holders that shall accept fuses dimensionally the same as Class H fuses. Each project shall supply one set of three spare fuses for each type and size fuse installed. Designer shall evaluate the need for a box for storage of spare fuses. If a box is installed, it shall be a metal box, designed to store fuses, mounted in a highly visible location, and labeled appropriately. SAFETY SWITCHES AND CIRCUIT BREAKERS Safety switches shall be heavy duty. To provide an immediate and observable point of electrical disconnect, locate a disconnect switch near each piece of fixed electrical equipment. Tandem branch circuit breakers are prohibited. Circuit breakers in branch circuit panelboards shall be bolt-on type. In existing buildings, new enclosed switches and circuit breakers shall match existing enclosed switches and circuit breakers. All safety switches shall have a durable label permanently attached to the inside of the cover describing the fuse size, type, current limiting ability and devices controlled. All safety switches intended for use on circuits where current limiting fuses are required shall be specified with rejection clips designed to permit installation of Class R fuses only. UPDATED - JULY 23, 2009 Page 6 of 10

7 Covers on safety switches shall be provided with a method of opening the cover without opening the switch. All safety switches shall have a grounding bar. Safety switches in mechanical rooms shall have NEMA 3R enclosures unless the environment or usage requires a more restrictive enclosure. Acceptable Manufacturers Square D General Electric Cutler-Hammer ADJUSTABLE SPEED DRIVES (ASD) VARIABLE FREQUENCY DRIVES (VFD) The design shall address the effects of VFD input current harmonics on the distribution system. Specify harmonic criteria and require field testing of harmonic performance where appropriate. Manufacturer shall provide harmonic analysis of the supplied VFD, total harmonics are not to exceed 3%. Provide VFD s that are compatible with the motors they control. Provide bypass switching capability when back-up equipment is not provided. Provide three (3) contactor bypass switching capability when back-up equipment is not provided. A variable frequency motor controller shall not serve more than one piece of equipment. In existing buildings, new variable frequency motor controllers shall match existing variable frequency motor controllers. Provide startup services for the Owner s personnel by a factory certified service representative. Minimum training time shall be 4 hours. Where motors are 40 HP and larger, VFD shall be 480 volts with step up transformers as required. Where we are not trying to maintain consistency with existing ASDs, acceptable manufacturers are: ABB Toshiba Square D Drives shall include manual bypass of the VFD for the following: 480 volt drives 125 HP and larger 208 volt drives 60 HP and larger Critical applications Drive Isolation Transformer (where required for changing voltage): General: factory assembled and tested, air cooled dry type transformer, having characteristics and ratings as indicated. Units shall be designed for 60 Hz service. Transformer shall be a three-phase, Delta Wye, or Delta-Delta unit. Grounding: the transformer shall operate with an ungrounded delta primary and a grounded wye secondary, or a corner grounded Delta secondary. UPDATED - JULY 23, 2009 Page 7 of 10

8 Core: Grain Oriented, non-aging silicon steel. Coils: continuous windings with no splices except for taps. Insulation system: UL recognized 220ºC. Performance shall be obtained without exceeding 150ºC temperature rise while operating in 30ºC ambient (24 hour average). Enclosure: constructed of heavy gauge steel with electrostatic applied finish. Enclosure shall be ventilated, dripproof with lifting holes. Sound levels shall not exceed 55 db. Non-linear rating: harmonic rating shall be equal to or greater than the harmonic distortion produced by the supplied VFD, as determined by the harmonic analysis supplied by the VFD manufacturer. IDENTIFICATION All switching, protective devices and metering on main distribution panels shall be identified with labels. Labels shall be adhesive backed vinyl or plastic with ½ inch letters. Identification labels are required for all distribution equipment from the service through branch circuit panelboards and motor control centers. The Design Professional shall specify the wording of identification labels. Label all receptacles on the cover plate with self-adhesive labels. Label shall indicate panel name and circuit number. All light fixtures shall be labeled with the panel number and circuit number from which they are fed. Place label out of public view. Coordinate label location with the Owner. All junction box covers shall be labeled with the panel number and circuit numbers contained in the junction box. Exposed boxes in finished areas: label on inside of cover. Exposed boxes in unfinished areas: label on outside of cover. Concealed boxes above accessible ceilings: label on outside of cover. FEEDERS All feeders shall have a separate copper grounding conductor installed. In no case shall the conduit or raceway be used as the grounding conductor. All conduit sizes and conductor numbers and sizes shall be shown on the drawings. All panelboards shall have separate grounding and neutral busses. All grounding and neutral wiring shall be terminated on the proper buss. No snap-in breakers shall be allowed. Bolt-in type breakers shall be used. Square D I-Line and GE Spectra Series are acceptable. BRANCH CIRCUITS All wiring systems shall be installed using conduit. Flexible wiring systems shall not be used. A separate grounding conductor shall be installed. Use of the conduit or raceway is not an acceptable grounding method. UPDATED - JULY 23, 2009 Page 8 of 10

9 All general purpose power circuits shall be a minimum of 20 amps. No piggyback breakers shall be allowed. General purpose power circuits in office areas shall not have shared neutrals. CONDUIT AND BOXES Conduit shall be supported from the building structure. Attachment to other pipes, conduits, ductwork, etc. shall not be allowed. Non-metallic conduit or boxes shall not be used except in wet locations. In cases where it is used, conduit 2 and smaller shall be a minimum of Schedule 80. Conductors carrying more than 150v to ground shall not be installed in conduits with conductors carrying less than 150v to ground. Schedule 80 PVC conduit will be utilized 1. Schedule 80 PVC conduit shall be utilized anywhere conduit emerges from concrete or where conduit may receive physical abuse. EMT shall not be used outdoors, in wet locations, in floor crawl spaces, or below 5 AFF. For Branch Circuits, the minimum conduit size shall be 3/4. For Feeders, conduit is to be sized at least one size above the NEC requirement of wire being installed or anticipated to be installed, with minimum size of 1. PVC conduit shall be used for underground electric circuits less than 600 volts that are: Under paved areas and areas scheduled to be paved. Next to permanent buildings, under formal planting beds and in extremely high ` areas that would be difficult to excavate due to regular heavy use. All other applications shall be direct bury. A red plastic tracer tape is to be buried 18 above the cable or conduit in all installations. PVC conduit for Blue Cap phones and parking gates shall be sized a minimum of 1. PVC conduit shall be Schedule 40 minimum weight and to be designed for electric application with all connections solvent welded. All metallic fittings shall be compression type rated for ground connection. Thin wall indenter fittings are prohibited. All fittings shall be galvanized steel or malleable iron. The use of flexible metal conduit shall be limited to recessed lighting fixtures. Six foot length maximum. Liquid Tight flexible metal conduit shall be used to connect rotating, vibrating or moveable equipment. Empty conduits shall have nylon pull cords installed with temporary caps or plugs. Raceways, boxes and their supports shall be compatible with the atmosphere of the area in which they are installed. UPDATED - JULY 23, 2009 Page 9 of 10

10 To reduce sound transmission, wall outlet boxes shall not be installed back-to-back in partitions. UPDATED - JULY 23, 2009 Page 10 of 10