DIVISION 16 ELECTRICAL SYSTEMS

Transcription

1 DESIGN AND CONSTRUCTION STANDARDS DIVISION 16 DIVISION 16 Division 16 of the Carnegie Mellon University Design and Construction Standards Manual addresses the following requirements for electrical systems on University projects GENERAL PROVISIONS BASIC ELECTRICAL MATERIALS AND METHODS POWER GENERATION HIGH VOLTAGE DISTRIBUTION SERVICE AND DISTRIBUTION LIGHTING SPECIAL SYSTEMS COMMUNICATIONS TESTING

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3 DESIGN AND CONSTRUCTION STANDARDS DIVISION GENERAL PROVISIONS The Design Consultant shall meet with the University Project Manager to develop and prepare a project program in accordance with Facilities Management Services requirements for new buildings and/or renovations. The Design Consultant is required to visit the site to verify existing conditions and to survey the area of work. Electrical Design Criteria The following are general electrical design criteria. The building under design may require some, not necessarily all, of these criteria. The Design Consultant shall, with the University Project Manager, identify the implementation of those systems that apply. Research buildings and office buildings shall be provided with a primary selector load break switch when medium voltage is supplied to the building. The mechanical systems shall be designed to be energy conserving and in accordance with ASHRAE/IES Standard The University is an ally of the Green Lights program of the Environmental Protection Agency (EPA) and is committed to the principle of installing the most efficient lighting systems. Primary Power Distribution Each feed into a building shall be status monitored to determine which feed is being used. Dry contact output shall be connected to the energy management system. Electrical Equipment Rooms Access shall be provided for replacement of the largest piece of equipment without cutting the equipment or removing walls. The rooms shall be adequately ventilated under automatic control and shall have a floor drain. The mechanical and electrical rooms shall not be adjacent to areas where the vibration and/or noise from the electrical equipment would be objectionable. Electrical rooms shall be separate and physically isolated. There shall not be any mechanical piping or ductwork allowed in electrical equipment rooms. Doors for electrical rooms shall open out and have a panic bar opener. Temporary Light and Power Complete installation of temporary lighting and power shall be in strict accordance with the latest edition of the National Electric Code and OSHA requirements. The Electrical Contractor shall provide fence lighting in accordance with the City of Pittsburgh s requirements. For additional information see Division 1 General Requirements, Section Temporary Utilities. Shut-Down of Utilities Refer to Division 1 General Requirements, Section Temporary Utilities. Record Drawings Refer to Division 1 General Requirements, Section Contract Close-Out. Rev 2005-A May 2005 P. 16-3

4 DIVISION 16 DESIGN AND CONSTRUCTION STANDARDS Access Panels Access panels shall be provided for all devices and controls that will not be readily accessible after completion of the project, but to which the University will later require access. Regulations and Permits All electrical work, equipment, and materials furnished and installed shall conform to the latest requirements of the following: National Electric Code (NEC) National Fire Protection Association (NFPA) Department of Labor and Industry, as applicable (OSHA) United States Department of Health and Human Services Federal Specifications Basic National Building Code (BOCA) American National Standards Institute (ANSI) Illuminating Engineering Society (IES) Institute of Electrical and Electronics Engineers (IEEE) National Electrical Manufacturers Association (NEMA) Underwriters Laboratories (UL) Factory Mutual (FM) Electrical work shall also conform to any other governmental or local authorities having jurisdiction. Standards All material and equipment shall be listed, labeled, or certified by a nationally-recognized independent testing laboratory where such standards have been established. Equipment of a class that no nationallyrecognized testing laboratory accepts, certifies, lists, labels, or determines to be safe will be considered acceptable, if not inspected or tested in accordance with a national industrial standard such as those of ANSI, NEMA, or the Insulated Cable Engineers Association (ICEA). Damage to Other Contract Work The Electrical Contractor shall be responsible for the repair of damages to other contractors work and to existing work areas. The Electrical Contractor shall repair said damages to the original condition to the satisfaction of the University. Calculations The Design Consultant shall provide the University Project Manager with the voltage drop, load, and fault current calculations BASIC ELECTRICAL MATERIALS AND METHODS Raceways Unless otherwise specifically approved by the University Project Manager, all new wiring in existing and new buildings shall be concealed. P Rev 2005-A May 2005

5 DESIGN AND CONSTRUCTION STANDARDS DIVISION 16 All conductors shall be run in electrical metallic tubing (EMT) except where otherwise required. Compression fittings shall be used for EMT. The minimum conduit size shall be 0.75 in. The use of armor-clad (AC) cable is prohibited. Metal-clad (MC) cable may be used in inaccessible ceiling and wall spaces, but shall not be exposed. The Design Consultant shall verify all other uses of MC cable with the University Project Manager. The use of ENT (non-metallic) conduit shall not be permitted without the written approval of the University Project Manager. Conductors rated 2 kv and above shall be run in rigid galvanized steel (RGS) conduit. Cable trays are acceptable for communication cable. They may also be desirable in certain research laboratories or facilities to contain equipment power and control cable. Conductors All wire shall be type THHN/THWN insulated solid copper. Minimum wire size shall be No. 12 AWG. Medium voltage power cable shall be 5 kv, single conductor, shielded with ethylene-propylene rubber. Splices shall be avoided wherever possible. However, if required, splice kits or hand splices shall be used. Reusable splices are not permitted. Switches and Receptacles Convenience receptacles shall be Hubbell, P&S, Bryant, or Leviton No. 5362; 20 amps; grounding-type NEMA rated. Switches shall be Hubbell, P&S, Bryant, or Leviton Nos. 1221, 1223, and Coverplates for switches, outlets, and receptacles shall be stainless steel finish, unless otherwise approved by the University. While wall surfaces are to receive wall coverings, the coverplates shall be high-impact nylon with color as selected by the Design Consultant. Duplex receptacles shall be mounted with ground terminal up at 18 in. above finished floor (AFF) and switches at 48 in. AFF. All existing device locations that will be reused shall receive new devices and coverplates. A minimum of 20-ampere circuits shall be provided for lighting and power. All lighting and power circuits shall be kept separate from each other, with dedicated separate lighting and power panels, unless impractical and approved by the University Project Manager. Some older buildings may have combined lighting and power panels. Common trip for all multiple pole breakers shall be provided. Ground fault interrupters shall be provided for all exterior circuits and all circuits in wet areas such as toilet rooms, kitchens, and wet labs. These interrupters shall comply with all codes. Ground fault circuit interrupter (GFCI) components that are in current production shall be used. For audio-visual applications, refer to Division 11 Equipment, Section Identification All electrical equipment and circuits shall be marked and labeled for identification purposes. Laminated nameplates shall be used on the exterior surfaces of all electrical apparatus, including switchboards, control center safety switches, circuit breakers, pull boxes, junction boxes, and panelboards. All panelboards, disconnect switches, and transformers shall be labeled indicating the source of power, voltage, and load. Rev 2005-A May 2005 P. 16-5

6 DIVISION 16 DESIGN AND CONSTRUCTION STANDARDS POWER GENERATION Generator Electrical equipment and associated piping and duct work shall be mounted on vibration isolators to minimize transmission of vibration and noise to building structures or spaces. All rotating equipment shall be balanced both statically and dynamically. The equipment supporting structure shall have no natural frequencies within plus or minus 20% of the operating speeds. The equipment while operating shall not exceed a self-excited radial vibration velocity of 0.10 in./sec or an axial vibration velocity of 0.05 in./sec when measured with a vibration meter. Emergency generators shall be diesel fueled as required by the City of Pittsburgh. Automatic Transfer Equipment The emergency system may be either 208Y/120 or 480Y/277 volt, 3-phase, 4-wire. It shall have an open transition 3-pole and switched neutral transfer switch. (Generator neutral shall be grounded as required for separately-derived sources with switched neutral transfer switches.) If elevators or motor-generator (MG) sets are connected to the generator, an in-phase retransfer relay shall be installed in the transfer switch so the generator does not trip the feeder breaker. Emergency Power Loads New construction projects shall have loads as required by the governing codes connected to the emergency power system. Equipment in new structures such as fire alarm systems, general management panels, security panels, environmental rooms, prime hood exhaust fans, critical computers, and emergency lighting in electrical and mechanical rooms shall also be provided with emergency backup power supply. Existing buildings shall only have loads connected to the emergency power system as required by the governing codes and as approved by the University Project Manager. The Design Consultant shall obtain load data on existing emergency generators from the University Project Manager HIGH VOLTAGE DISTRIBUTION Substation Switchgear Medium voltage 5kV circuit breakers shall be of vacuum drawout type. Load break fuse selector switches shall be utilized for all building service entrances. Switches shall be 5kV equal to Westinghouse WLI with CLE-type fuses. Transformers Transformers shall be mounted on isolators to minimize transmission of vibration noise to building structure. The sound pressure levels around electrical equipment in equipment spaces shall not exceed 85 dba on the A scale at any point 3 ft from the equipment with all equipment in the room operating. Indoor or outdoor transformers with primary voltage of 5 kv and sized 300 kva and above shall be dry type design with 80 C (176 F) temperature rise. K-rated transformers shall be utilized in electronic data processing equipment distribution systems. Approved Manufacturers The preferred manufacturers for all switchgear are as follows: P Rev 2005-A May 2005

7 DESIGN AND CONSTRUCTION STANDARDS DIVISION 16 Westinghouse Electric/Cutler Hammer General Electric Square D Powerlogic SERVICE AND DISTRIBUTION Service, Disconnect, Metering Generally, electrical distribution systems shall be 480Y/277V, 3-phase, 4-wire for lighting and mechanical loads and a 208Y/120V, 3-phase stepdown transformer for small power loads. The main distribution panel (MDP) shall have an amp meter, voltmeter, kwh meter, amp, and volt switches. The main feed shall have remote monitoring capability for kwh use and kw demand. Pulse outputs (kwh) and a 4 to 20 ma signal (kw) shall be sent to the Campus-wide Energy Management System. Alternatively, meters may be connected to the Campus-wide Energy Management System via BACNet/IP, BACNet/MSTP or ModBUS interface. Laboratory, computer, and data processing rooms and shop panelboards shall have emergency shut-off devices located away from telephones and light switches. They shall be clearly label Power Disconnect. Green wire ground shall be provided in each building riser, in each feeder circuit, to each 3-phase motor circuit, to each fixed device branch circuit, and to each receptacle circuit. The main distribution panels shall contain one main breaker and several branch feeder breakers. The designer shall submit load calculations for main distribution panels with diversity factors. All calculations shall be in accordance with the NEC. Fused switches shall not be used. Analyzers are not required for motor overcurrent protection; circuit breaker type protection devices shall be used instead. The preferred manufacturers for meters are: Square D Powerlogic Cutler Hammer IQ Analyzer Motors and Motor Starters All motors shall be high-efficiency. Motor starters shall be combination thermal magnetic circuit breaker type for motors up to 30 hp. Motors over 30 hp shall use thermal magnetic reduced-voltage autotransformer-type starters. Variable frequency drives shall be used when approved by the University Project Manager. Fused switches shall not be used for motor overcurrent protection; circuit breaker type protection devices shall be used instead. The controller shall contain the minimum following features: Manual bypass consisting of a full voltage starter and a normally-open contact, electrically and mechanically interlocked with the starter Isolation contact to minimize possible shock hazard at the motor terminals when the controller is off Status indicating lights to aid in troubleshooting Capability of supplying 150% of rated full load current for one minute at maximum ambient temperature Instantaneous overcurrent trip to protect against output phase to phase (short circuit) and output phase to ground (motor ground fault) Overvoltage trip to protect against high line voltage Rev 2005-A May 2005 P. 16-7

8 DIVISION 16 DESIGN AND CONSTRUCTION STANDARDS Undervoltage trip to protect components against overtemperature Overtemperature trip to protect components against overtemperature Adjustable acceleration rate, 0-60 sec Analog speed meter On-off-auto control with manual speed adjustment in the manual position Isolated signal follower, current 4-20 ma, voltage 0-10V dc or pneumatic 0-15 psi, compatible with the building s automatic temperature control system If isolation transformers and/or reactors are required to make the drive operate properly because of transients, the drive manufacturer must include them. The entire assembly shall be by one manufacturer. The preferred manufacturers for motor starters are as follows: Square D Powerlogic Allen Bradley Westinghouse/Cutler Hammer General Electric All internal control wiring shall terminate at screwed terminal strips and be properly identified for connecting field control wiring. Motors less than 0.75 hp shall be single-phase, 115 V for operation on 120-V circuits. Motors 0.75 hp and larger shall be 3-phase. Motors operating on 3-phase, 208 V shall be rated at 200 V. Motors operating on 3-phase, 480 V shall be rated at 460 V. Power factor correction shall be provided on all motors larger than 25 hp. On centrifugal chillers, a wye-delta, closed-transition motor (hermetic) and starter shall be used. For standards related to variable speed drives, refer to Division 15 Mechanical Systems, Section Motor Control Centers Structures shall be totally enclosed, dead front, free standing. Guide rails for control units, accessible wireways, and terminal blocks for control wiring shall be provided. Starters shall be of the combination type with circuit breakers. Each starter shall have two normally-open and two normally-closed auxiliary contacts wired to the terminal blocks, hand-off-auto switch, red run light, and green off light. Starters shall be wired so that at the loss of electrical power, they revert back to automatic operation when power is restored. The motor control center shall be sized for a minimum 25% spare capacity. It shall be complete with bus bar, rails, wireways, and other appurtenances so that, other than new starters, no additional hardware is required for future expansion. Starter control circuits must include wiring terminals on terminal strips for interconnection with the University s Building Automation System. All controls shall be located on the outside of switches, control cabinets, controllers, and motor control centers. For fire pump controllers, the Power Available Visible Indicator bulbs frequently burn out and have been cited by fire and insurance inspectors. Therefore, long-life lamps such as neon shall be provided for these indicators. P Rev 2005-A May 2005

9 DESIGN AND CONSTRUCTION STANDARDS DIVISION 16 Panelboards All branch panelboards shall be 42 circuit panels with bolt-on branch breakers. A separate panel shall be located in each laboratory. All panels shall have panel schedules on the drawings as well as in each panel. Branch circuit panels shall have all of their circuits on the same floor. Panelboards shall have an isolated neutral bus and a ground bus bonded to the cabinet. Group-installed panelboards shall have separate trim. Where flush panelboards are used, a 1-in. conduit shall be installed for every three spare poles to a point above the suspended ceiling. Green ground wire shall be installed with all circuits. Panels serving loads in only one room may be located in that room. Panels serving more than one room shall be located in the corridor or other public space. Panelboards shall NOT be installed in janitor closets. Breakers shall be of bolt-on type, 10,000 ac minimum for 120/208 V, 14,000 ac minimum for 480/277 V. Available fault current shall be verified prior to specifying. Contractors shall be required to keep directories up to date, to indicate all deletions and additions, and to note the date of all changes on the directory. Panelboards shall contain surge suppression. Circuit breakers for lighting branch circuits shall be rated SWD (switching duty related). The main service entrance circuit breaker shall have true root mean squared (RMS) ground fault sensing. Low voltage distribution overcurrent devices shall be molded case circuit breakers: feeder circuit/ branch circuits. The branch circuit wiring shall include the home run number, the conduit size, and the number of wires in the conduit, including a ground wire. For renovation projects, all wire that is original building wiring and is obsolete such as RH and RHW shall be replaced with type THHN/THWN. All branch circuits shall have separate neutrals. The preferred manufacturers for panelboards, bus duct, transformers, and disconnect switches are as follows: General Electric Square D Powerlogic Westinghouse/Cutler Hammer Transformers The sound pressure levels from motors, elevators, and transformers and such in electrical equipment rooms shall not exceed 85 dba on the A scale at any point 3 ft from the equipment with all equipment in the room operating. Surge Suppression Surge suppression receptacles shall be provided at individual outlets as specified by the University Project Manager. The device shall be able to absorb a 6,000 V transient surge, suppress 140 J min, and suppress 13,000 A. The suppression device shall be UL listed to Standard 498 and 1449 CSA Spec. C22.2 and IEEE The preferred manufacturers for surge suppression receptacles are as follows: Hubbell Leviton Rev 2005-A May 2005 P. 16-9

10 DIVISION 16 DESIGN AND CONSTRUCTION STANDARDS Grounding and Lightning Protection All metallic cable sheaths, including flexible metallic conduit, shall be grounded and bonded properly. Also, all roof projections, antennas, metal rails, parapet caps, and other items as needed shall be grounded to provide lightning protection as required by codes LIGHTING Lamps All incandescent lamps shall be energy saving, rated for 130 V, capsulate or traffic type. Compact fluorescent ballasts shall be reduced harmonic with total harmonic distortion (THD) less than 33%. The use of incandescent lamp sources shall be kept to a minimum. In general, incandescent lamps shall be used only for dimming applications. All other applications shall be reviewed and approved by the University Project Manager. The Design Consultant shall consider maintenance items such as lamp life, lumen deprecation, accumulation of dirt on the lens, and lower reflectance of ceiling and walls. Some lamps such as the 13 W PL lamps and 250 W metal halide have had a high failure rate. Consideration shall be given to ease of lamp replacement and overheating of ballasts caused by poor ballast location. Ballasts All fluorescent lighting shall use F32T8 lamps with electronic ballasts, reduced harmonic with THD less than 20%. Lighting Controls All outdoor lighting shall be controlled by photocells. Photocells shall be placed to provide the optimum turn-on time for security considerations. Computer rooms shall use video display terminal (VDT) type fixtures. Two levels of switching shall be provided for all other areas. Shielding Prismatic shielding in fluorescent troffers shall be KSH-type No. 12 at in. nominal thickness used for general purposes, such as corridors. Parabolic louvers shall be 2 in. deep in areas such as classrooms, computer rooms, and offices. Approved Manufacturers Two manufacturers shall be listed for each lighting fixture. Proprietary luminaires are acceptable when approved by the University Project Manager. Quality of Illumination Visual comfort probability (VCP) in offices shall be 80 or greater. In offices and classrooms, the maximum to minimum foot-candle ratio shall never be greater than two to one. For site lighting standard, refer to Division 2 Sitework, Section For audio-visual applications, refer to Division 11 Equipment, Section P Rev 2005-A May 2005

11 DESIGN AND CONSTRUCTION STANDARDS DIVISION 16 Area Recommended Average Foot-Candle Illumination Conference, seminar, offices Service areas: corridors, stairways, locker rooms, storerooms, lobbies, etc. Library stacks Study carrels 50 Card files 100 Laboratories Classrooms and lectures Offices/classrooms/VDT Computer rooms with (VDT terminals) Drafting rooms Mechanical, electrical rooms 20 Swimming pools 50 Handball courts 30 Covered parking facilities Walkways Entrances 10 Recommended Average Foot-Candle in. above finished floor (AFF) ft-0 in. AFF) 1 (minimum) SPECIAL SYSTEMS Fire Alarm System Fire alarm systems shall be designed in accordance with the following: NFPA-72, the National Fire Alarm Code NFPA-70. the National Electrical Code International Building Code- 2003, Section 907 International Fire Code- 2003, Section 907 and any applicable local codes or amendments to any of the above. The fire alarm system shall be addressable, with individual addresses for each alarm initiating device, such as manual pull stations, smoke or heat detectors, waterflow or pressure switches, etc. The fire alarm system shall be connected to normal/emergency power, and battery backup power shall be provided in the fire alarm control panel in accordance with NFPA requirements. Control panels shall be of modular design for ease of system expansion, and shall be protected with adequate built-in surge suppression. The fire alarm system shall be capable of disabling and re-enabling no less than nine (9) separate output groups or functions, such as audible and/or visual alarm signals, release of fire shutters, release of door hold-opens, etc. This feature shall be made available through the use of push buttons located at the front of the alarm control panel, and these buttons shall be clearly labeled describing the outputs that each will enable/disable. The act of resetting the fire alarm panel shall not change the status of enabled/disabled Rev 2005-A May 2005 P

12 DIVISION 16 DESIGN AND CONSTRUCTION STANDARDS outputs, and the alarm control panel will clearly indicate any outputs while they are disabled. The required configuration of these buttons will be provided by the University Facilities Management Services Department. Manual pull stations shall not have a glass rod or plate that must be broken to activate the system. A graphic LED annunciation panel which will identify the fire alarm device, floor, and zoned location on the floor in alarm shall be installed in a location that is acceptable to the local authorities and to the University. This annunciator shall be mounted with the graphic display properly oriented to give the viewer a clear indication of the building layout and the location of any alarm being reported. Audio/visual fire alarm signals shall consist of an electronic horn and xenon strobe suitable for mounting in a four (4) inch square back box. In finished areas, where surface mounting of devices is necessary, a factory finished back box shall be used. Wall mounted audio/visual signaling units shall be mounted no more than ninety (90) or no less than eighty (80) inches above the finished floor, or in areas having extremely low ceilings, no less than six (6) inches below the ceiling. Audible warnings provided by electronic horns shall be programmed at the fire alarm control panel to produce an intermittent, broken, or march time signal. Visual xenon strobe warning signals shall be provided in spaces required by ADA (Americans with Disabilities Act) guidelines. Where voice-alarm systems are required, the Design Consultant shall delineate all speaker placement and wiring requirements to assure for correct annunciation of the alarm signal to all zones of the building. The University s Environmental Health & Safety Office will provide the message that will be delivered by the system to building occupants. Smoke detectors shall be installed in public areas as required by code or by the University. When installed within common building areas, smoke detection shall be a combination of both ionization and photoelectric types with alarm verification. In addition to transmitting alarm signals to a central monitoring station, the fire alarm system shall transmit alarm, trouble, and supervisory signals to the University Police alarm monitoring station. Fire alarm systems and devices shall be manufactured by Siemens Cerberus (Pyrotronics) or by Notifier, Incorporated and shall be connected to the University s centralized monitoring system via dedicated copper lines. The System Supplier shall provide building graphics that are suitable for display on the University s central monitoring system. The System Supplier shall also provide a complete set of fire alarm drawings to the University Environmental Health & Safety Office for preparation of customized fire alarm device messages. The drawings shall indicate room numbers and uses, all alarm device types, and their respective identification numbers. The Design Consultant shall prepare the design layout of the alarm panel, including appropriate zone lights and device type lights for graphic annunciation. Based upon the type of building occupancy, he shall recommend the styles of alarm initiating device and alarm notification device circuits to be used. The Design Consultant shall provide complete sets of fire alarm drawings and specifications for review by the University Facilities Management Services Department (FMS) and the University Environmental Health & Safety Office (EH&S). Certification testing of the completely installed fire alarm system shall be conducted by the Installing Contractor, the System Supplier, the University FMS Lifesafety Supervisor and/or the University EH&S Fire Safety Specialist, with the Authority having Jurisdiction (Pittsburgh Fire Prevention Division- Bureau of Fire). A certificate of satisfactory acceptance shall be acquired when testing has been completed. P Rev 2005-A May 2005

13 DESIGN AND CONSTRUCTION STANDARDS DIVISION 16 Clock Systems All new buildings shall have central clock systems. In corridors, clock outlets shall be installed for synchronous clocks and tied into the main campus system in the following buildings: Hamburg Hall University Center Wean Hall Doherty Hall Porter Hall, which feeds: Baker Hall Scaife Hall Hamerschlag Hall Margaret Morrison College GSIA Hunt Library College of Fine Arts In large classrooms, auditoriums, gymnasium, or office areas, clock outlets shall be provided only as directed COMMUNICATIONS General Information and Instructions Designers should refer to the standard specifications for communications equipment provided by the Cable Plant office. These specifications should be used without modification on all jobs involving data or telecommunication equipment, cabling or spaces that house such equipment or cabling. Requests to modify these specifications or drawings in any way should be referred to the Cable Plant Manager at Carnegie Mellon. These documents are available on-line TESTING Cleaning Upon completion and prior to testing and commissioning, the Contractor shall thoroughly clean all electrical devices to remove grease, metal cuttings, dirt, protective covers, and other foreign substances. Testing The Contractor shall test all work for shorts, grounds, and open circuits. The Contractor shall also perform the following inspection and tests, and certify in writing that all tests and inspections have been made and that all problems and defects have been properly corrected. Visually check all cables and connections. Make continuity checks for all power, control, and signal cables as well as conductors. Make insulation-resistance tests for all 600 V power cables and conductors. Check all ac and dc control circuits for open and short circuits. Rev 2005-A May 2005 P

14 DIVISION 16 DESIGN AND CONSTRUCTION STANDARDS Exercise all motor starters from motor control center push buttons. Check motors for proper rotation and measure motor current under load. Comply with Section for testing of emergency power generators. In general, comply with National Electrical Code NFPA 70 Article (a) through (e) for test procedure. As a minimum, the National Electrical Testing Association (NETA) Acceptance Testing Specifications (latest version) shall be followed to test all new electrical systems and equipment. Also as a minimum, the NETA Maintenance Testing Specifications (latest version) shall be followed to test all existing electrical systems and equipment. P Rev 2005-A May 2005