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InspectionFollowing installation, and sometimes at intervals during installation, the contractor or owner must contact the AHJ to schedule an inspection. An inspector evaluates the installation's conformity to application documents and applicable codes, laws, and regulations. Upon successful completion of all necessary inspections, the AHJ issues a certificate of approval or completion, authorizing the operation and connection of the system to other electrical systems, as applicable. Copies of certificates should be held by the system owner for documentation and insurance purposes, as well as for arranging interconnection approval with the electric utility in the case of interactive systems. When inspections find a system to be non-compliant, the AHJ provides written notice of the discrepancies. Final approval is then contingent on rectifying the problems and passing a follow-up inspection. The AHJ may grant extensions to the permit expiration date upon request. To facilitate the inspection process, the installer should have copies of all documentation submitted for the permit application on hand, including drawings, equipment specifications, and manuals. Any changes from the original design should be indicated on as-built drawings or as modifications to originals. All equipment should be accessible to inspectors, particularly equipment containing field-installed wiring. All aspects of the electrical installation governed by codes and standards are subject to inspection, including conductor sizes, wiring methods, overcurrent protection, and grounding. For PV systems, most inspectors will pay particular attention to general electrical workmanship and safety, and the proper application of information and warning labels on system equipment. Workmanship The NEC requires electrical equipment to be installed in a "neat and workmanlike manner." The installation should include structurally adequate supports, plumb and level mountings. proper conduit bends, and other quality matters not otherwise covered by NEC safety requirements. Since AHJs may interpret this requirement differently, the National Electrical Contractors Association (NECA) and industry partners publish standards to help define performance and workmanship expectations for electrical construction. One example is ANSIINECA 1, Standard Practice of Good Workmanship in Electrical Contracting. These standards are often referenced in contract documents to establish installation quality expected by engineers, contractors, and customers. The AI-IJ has the responsibility of investigating the causes and circumstances of any fires explosions or other hazardous conditions affecting public health safety, or welfare. --9. Quality workmanship results in a neat and efficient electrical installation. Workmanship; Scholt Solar --10. Dedicated space is the clear space reserved around electrical equipment for the existing equipment and potential future additions. Dedicated Space DEDICATED SPACE FROM FLOOR TO DEL WIDTH EITHER 6 ABOVE / EQUIPMENT TO CEILING; CEILING Working Space PV system inspections also ensure that there is adequate access and safe working space around all electrical equipment. Meeting these requirements can be challenging when installing PV system components in buildings with existing electrical systems. Building-integrated PV systems can also present special challenges. Article 110 requires safe access and working space be maintained for electrical equipment operating at less than 600 V, which covers the majority of PV systems. Dedicated space is the clear space reserved around electrical equipment for the existing equipment and potential future additions. For indoor installations, dedicated space for electrical equipment must be equal to the width and depth of the equipment and must extend from the floor to a height of 6' above the equipment or to the structural ceiling, whichever is lower. No piping, ductwork, or other equipment not related to the electrical installation shall be located in this space. Working space is the clear space reserved around electrical equipment so that workers can inspect, operate, and maintain the equipment safely and efficiently. The depth of working space is the minimum clear space in front of electrical equipment with exposed live parts. This distance depends on the nominal voltage of the equipment and on whether similar equipment with live parts is located on the other side of the space. For less than 150 V, the clear working space must be at least 3' deep. For equipment operating between 151 V and 600 V, 3' of depth is required if exposed live parts are on only one side, 3.5' of depth is required if grounded parts are located on the opposite side of the space, and 4' of depth is required if live parts exist on both sides of the space. 1. With special permission from the AHJ, smaller working spaces may be permitted for equipment operating at no greater than 30 VAC or 60 VDC. This provision may apply, For example, to small stand-alone PV lighting systems with 12 VDC or 24 VDC loads. When equipment is not permitted to be serviced in an energized state, these requirements may not apply. The width of the working space in front of any electrical equipment shall be at least 30" or the width of the equipment, whichever is greater. This space may overlap the width of working space for adjacent equipment. The working space must also allow at least 90° openings for any doors or hinged panels on equipment. Working heights must be at least 6.5' or the height of equipment, whichever is higher. At least one entrance of sufficient area must be provided for access to working spaces. In all cases, storage of materials must not block or interfere with safe access to equipment. === CEILING WORKING; SPACE IN FRONT OF ELECTRICAL EQUIPMENT 30" WIDE OR WIDTH OF ___ EQUIPMENT, WHICHEVER IS GREATER 3' TO 4' DEEP, DEPENDING ON SITUATION --11. Working space is the clear space reserved around electrical equipment so that workers can install, inspect, operate, and maintain the equipment safely and efficiently. Work Space DOORS CAN OPEN AT LEAST 90° 6.5' HIGH OR HEIGHT OF EQUIPMENT, WHICHEVER IS GREATER === Accessibility Accessibility is explicitly covered throughout the NEC and evaluated during electrical inspections. There are different meanings for accessibility, depending on context. Accessibility with regard to equipment means that close approach is possible and the equipment is not protected by means such as locked doors, fencing, or elevation. Accessibility with regard to wiring means that the conductors are capable of being removed or exposed and are not concealed by a building structure or its finish. When parts of an electrical installation are to be concealed at the completion of construction, interim inspections may be scheduled to approve this work before covering. For example, pre-drywall inspections are required when any electrical or mechanical work will become permanently concealed behind walls. While this is not typically a concern for retrofit PV installations, it may impact new construction when PV systems are installed at the same time as the building electrical system. When the completed installation restricts access to any equipment, wiring systems, or equipment labels, the installer should make provisions to allow access to these areas for inspections. For example, certain PV modules may be attached in a way that allows them to be easily removed from the array for inspection of labels, junction boxes, and grounding connections behind them. Live Parts Live parts are energized conductors and terminals. Live parts must be protected from accidental contact for any electrical equipment operating at 50 V or more. This can be accomplished by using approved enclosures and conduit, elevating the equipment 8' or more from the floor or work surface, or locating the equipment in a special room. When live parts are installed in protected locations, warning signs are required at the entrance prohibiting access to unqualified persons. For one- and two-family dwellings, access to energized PV circuits over 150 V is prohibited to other than qualified persons. This protection can be in the form of enclosures that are lockable or require tools for access. Panel covers that are readily accessible and can be easily opened by unqualified persons don’t meet these requirements. Battery terminals are exposed live parts that must be adequately protected to prevent accidental contact. This protection includes battery or terminal covers, or installing batteries in enclosures. Labels and Marking All electrical equipment must have durable labels identifying the manufacturer and any listing marks or certifications. Article 690, Part VI addresses additional marking requirements for PV systems. Labels are required for individual components and are typically applied by the manufacturer. For example, PV modules, inverters, and charge controllers must include voltage, current, and power ratings. Labels are also required at certain points in the electrical system to identify the locations, purposes, or interfaces of various components. These labels are prepared by the installer. The labels identify power sources, utility interconnection information, disconnects, and safety hazards. All labels must be visible and accessible during inspections. --12. Rubber or plastic terminal covers are used to prevent shorts across battery terminals during maintenance. --13. PV module labels must include terminal polarity in formation and ratings for volt age, current, and power. PV Module Labels. Module labels must include the terminal polarity, the maximum overcurrent protection device rating, and six module performance parameters: open-circuit voltage, maximum power (operating) voltage, maximum system voltage, maximum power (operating) current, short-circuit current, and maximum power. Additional, but not required, information may include allowable conductor types and sizes, temperature ratings, and terminal torque specifications. AC module labels must identify the terminals and ratings for nominal operating AC voltage and frequency, maximum AC power and current, and maximum overcurrent protection device rating. Array-Disconnect Labels. The array (DC) disconnect must be clearly identified on a permanent and easily visible label. Since the array is a power source, its operating parameters must also be included on the disconnect labeling. The label must include the maximum power (operating) current, maximum power (operating) voltage, maximum system voltage, short- circuit current, and rated output for charge controllers (if installed). AC-Disconnect Labels. AC disconnects must be clearly identified and include critical circuit information. A visible label must include the maximum AC output current and the operating AC voltage. 5. This information is obtained from inverter specifications. Additionally, when all terminals of a disconnect device may remain energized in the open position, the device must include a warning sign. The sign shall be clearly legible and have the following words or equivalent: "WARNING-ELECTRIC SHOCK HAZ ARD. DO NOT TOUCH TERMINALS. TERMINALS ON BOTH THE LINE and LOAD SIDES MAY BE ENERGIZED IN THE OPEN POSITION." This is especially important for AC disconnects in interactive systems and for battery bank disconnects be cause there are power sources on both sides of the disconnects. --14. A label indicating the operating cur rent, operating voltage, maximum system voltage, and short-circuit current must be displayed at the DC disconnect of a PV array. PHOTO VOLTAIC ARRAY DC DISCONNECT SWITCH --15. Labels identifying the PV system as a power source and including its maximum output operating current must be posted at the AC disconnect of a PV system. - ± Labels PHOTOVOLTAIC STEM UTILITY DISCONNECT SWITCH; MAXIMUM AC OUTPUT CURRENT; 41A OPERATING AC VOLTAGE: 480V PV ARRAY RATING: 26.7KWDC AT STC SYSTEM RATING: 21.4KWAC AT P Point-of-Connection Labels. For interactive systems, a label must be located at the point of interconnection and must identify the system as interconnected with utility service. This point-of-connection identification will likely be in addition to other AC disconnect label requirements. The point-of-connection label may be at a back-fed circuit breaker in the main power distribution panel or at an AC disconnect switch. Battery-System Labels. For PV systems with batteries or other forms of energy storage, sys tem labels must indicate the maximum operating voltage, equalization voltage (if applicable), and the polarity of the grounded circuit conductor (typically the negative conductor). Additional information such as the nominal voltage or capacity may be included on this label. Additional warning labels about chemical safety are recommended. == Battery-System Labels --16. PV systems with batteries must have labels indicating the battery maximum operating voltage, equalization voltage, and polarity of the grounded circuit conductor. == PV systems may include optional watt hour meters in addition to the utility service meter These may be used for monitoring, production incentive metering, or other purposes It’s best practice to label each meter with its purpose to avoid confusion with required metering devices Power-Source Identification. For stand-alone PV systems, a permanent plaque or directory must be installed on the exterior of the structure identifying the presence of a stand-alone electrical system and indicating the location of the system disconnects. For interactive systems, a permanent directory must indicate the locations of the service disconnect and the PV-system disconnect, if they are not located together. This safety requirement is in place to alert emergency and maintenance personnel to the presence of other power sources when utility service is disconnected. Ground-Fault-Indicator Labels. Ground- fault indicators require labels for PV arrays mounted to roofs. These labels should be located near the ground-fault device and must state the following: "WARNING-ELECTRIC SHOCK HAZARD. IF A GROUND FAULT IS INDICATED, NORMALLY GROUNDED CONDUCTORS MAY BE UNGROUNDED and ENERGIZED." Ungrounded-System Labels. In addition to any other required labels, special warnings must be applied to ungrounded systems. In an ungrounded system, leakage currents below the level required to trip the ground-fault device may be present on the conductors, presenting an electrical shock hazard. For this reason, un grounded systems must be labeled with the following: "WARNING-ELECTRIC SHOCK HAZARD. THE DC CONDUCTORS OF THIS PHOTOVOLTAIC SYSTEM ARE UN GROUNDED and MAY BE ENERGIZED." This warning must be displayed at each junction box, combiner box, disconnect, and any other device where ungrounded conductors may be exposed during service. Single 120 V Supply Labels. Stand-alone inverters with 120 V output are permitted to supply 120/240 V distribution panels, but no 240 V loads or multiwire branch circuits may be connected. The panelboard must be marked with the following label or equivalent: "WARNING-SINGLE 120-VOLT SUPPLY. DO NOT CONNECT MULTIWIRE BRANCH CIRCUITS." --17. Single 120 V supply pane/boards must be marked to prohibit connection of multi-wire or 240 V branch circuit loads. --18. Maintenance or operation labels are recommended for detailing nominal equipment settings and adjustment procedures. DC COMDINER BOX REFER SERV TO AUTHORIZED PERSONNEL NG USER SERV PARTS NEIc Operating Parameters. Additional recommended labels include operating, maintenance, or extra safety information. Examples include charge controller and inverter setpoints and maintenance schedules, and the name and contact information of the system installer. Inspection Checklist An inspection checklist provides an extensive list of code references for PV systems based on the NEC and industry standards. NEC section citations are included for reference. However, since code numbers can change with cycle revisions, the citations may need to be updated. A general inspection checklist is not intended to include every applicable requirement, but can be a useful guide to common PV system issues for inspectors, as well as PV system designers, installers, operators, and owners. Also, since many component installation practices are governed by equipment manufacturer's instructions, the inspector should reference these materials as well as other documentation (schematics and equipment specifications) as part of a plans review or an in-field inspection. SUMMARY:• Building codes are applicable to the construction and electrical aspects of PV systems, just as for any other project. • A building code must be adopted by the local jurisdiction to apply and be enforceable. • The authority having jurisdiction (AHJ) approves equipment, materials, installations, and procedures by issuing permits, conducting inspections, and granting certificates of approval or occupancy. • The use of approved equipment is required by the NEC and facilitates the plans review, permitting, and field inspection processes. • Underwriters Laboratories is the best-known NRTL and provides several types of certification marks, each with specific meaning. • All electrical work should be performed by qualified persons. • In some states, it’s illegal for covenants or neighbors to restrict the solar resource to a person's property or to prohibit the installation of renewable energy systems. • Building permits issued by city or county building departments authorize construction work to begin and establish the inspection requirements. • Permit applications require certain information about the scope and specifications of the work, typically including the construction tasks, location, permit applicant, expiration date, and inspection requirements. • If any portion of an electrical design is determined to be noncompliant with the applicable standards during a plans review, corrected designs must be resubmitted. • The permit must be posted in a conspicuous location on the job site premises for the duration of the project. • Following installation, and sometimes at intervals during installation, the contractor or owner must notify the AHJ to schedule an inspection. • An inspector evaluates the conformity of an installation to applicable codes, laws, and regulations. • PV system inspections ensure that there is adequate access and safe working space around all electrical equipment. • All electrical equipment must have labels identifying the manufacturer and any listing marks or certifications. • Labels are required at certain points in the electrical system to identify the locations, purposes, or interfaces of various components, and are prepared by the installer. • An inspection checklist provides an extensive list of code references for PV-systems based on the NEC and industry standards. TERMS:• A building code is a set of regulations that prescribes the materials, standards, and methods to be used in the construction, maintenance, and repair of buildings and other structures. • A model building code is a building code that is developed and revised by a standards organization independently of the adopting jurisdictions. • An authority having jurisdiction (AHJ) is an organization, office, or individual designated by local government with legal powers to administer, interpret, and enforce building codes. • A plans examiner is a local official qualified to review construction plans and documentation for compliance with applicable codes and standards. • An electrical inspector is a local official qualified to evaluate electrical installations in the field for compliance with applicable codes and standards. • A nationally recognized testing laboratory (NRTL) is an OSHA-recognized, accredited safety testing organization that certifies equipment or materials to meet applicable standards. • Listing is the process used by an NTRL for certifying that equipment or materials meet applicable standards. • A qualified person is a person with skills and knowledge of the construction and operation of electrical equipment and installations and is trained in the safety hazards involved. • A construction bond is a contract in which a surety company assures that a contractor will complete their work in accordance with contracting laws. • A permit is permission from the AHJ that authorizes construction work to begin and establishes the inspection requirements, but does not represent an approval of compliance with codes and standards. • A plans review is an evaluation of system-design documentation as part of the permitting process. • Dedicated space is the clear space reserved around electrical equipment for the existing equipment and potential future additions. Working space is the clear space reserved around electrical equipment so that workers can inspect, operate, and maintain the equipment safely and efficiently. QUIZ:1. Why are applicable building codes sometimes different between local jurisdictions? 2. Who is responsible for ensuring that building codes are followed properly? 3. Explain the difference between products bearing the UL Listing Mark and those bearing the UL Classified Mark. 4. How does contractor licensing improve the likelihood of quality installations? 5. What types of documents are commonly required for permit applications? 6. Explain the difference between dedicated space and working space. 7. How can inspection checklists be used by installers prior to the PV system-inspection by the AHJ? Next: Photovoltaic Systems--Commissioning Prev: PV Inspection |