About Matt Piantedosi

Transcription

1 2017 NFPA Conference & Expo Solar PV System Inspections Best Practices and Commonly Found Violations Presented by: Matt Piantedosi Manager of Solar Field Operations The Cadmus Group About Matt Piantedosi Manager of Solar Field Operations BS Electrical Engineering Western New England College Inspected over 600 residential/commercial PV systems Licensed Master Electrician in MA and NH Licensed Journeyman Electrician in MA, RI, and CT Working in the trade for over 17 years B. A. Piantedosi Jr. Master Electrician Logan Electrical Company IAEI Boston Paul Revere Chapter Executive Board Member 2 About The Cadmus Group Renewable energy technical and economic expertise More than a decade of experience aiding clients to develop and support renewable energy in New England. Cadmus performs solar PV quality assurance inspections and design reviews for: Massachusetts Clean Energy Center Commonwealth Solar Program Solar Loan Program Solarize Massachusetts Mass Solar Connect Rhode Island Renewable Energy Fund, Renewable Energy Growth New York State Energy Research and Development Authority Various PV installers/investors Provide Owner s Agent Technical Assistance Department of Energy Resources Green Communities 3 1

2 Presentation Outline Cadmus PV Inspections An Introduction Common Trends PV System Code Compliance Best Practices Opportunities for Improvement 4 Cadmus PV Inspections Typically 1 2 hours onsite Determined by quality observed and complexity A comprehensive inspection of all components. Program compliance: Equipment verification Production/TSRF Technical NEC compliance 5 Cadmus PV Inspections Random & Targeted New installers to program Expedited installers Post AHJ Inspection Work with installers, inspectors to resolve issues by providing guidance and education. 6 2

3 Our Data Driven Approach to PV Inspections Data collected during PV inspections is used to track broad industry issues and trends, as well as provide targeted feedback to improve practices. 7 How We Classify Issues Each inspection is scored from 1 (poor) to 5 (excellent) based on how numerous and severe the issues are Issues classified as: Incidental Minor Major Critical 8 Incidental Non Conformance (4) Incidental issues are not expected to impact system operation or safety under normal operating conditions but still represent non compliance with relevant codes/standards. Examples include: Missing screws on indoor enclosure covers (but cover is still secure and renders interior of enclosure inaccessible) Installation debris (e.g., bits of wire, packing materials) left onsite Poor wire management that is not expected to cause a fault condition Equipment installed does not match Program records but is considered equivalent Missing/incomplete labels Incorrect color code on wires 9 3

4 Minor Non Conformance (3) Minor issues pose a mid to long term risk of system failure or safety hazard Bonding neutral to ground downstream of service disconnect Insufficient clearance around boxes Undersized circuit protection (nuisance tripping) Improperly supported conductors or conduit 10 Major Non Conformance (2) Major issues are deemed likely to impact system performance or safety in the short term, though they do not pose an immediate hazard Missing equipment grounding Missing or undersized grounding electrode conductor Improperly secured PV modules Missing/inadequate thermal expansion joints in long conduit runs 11 Critical Non Conformance (1) Critical issues pose an immediate risk of system failure and/or safety hazard. Often, we shut down systems with this level of defect for safety reasons. Exceeding current limits on busbars and/or conductors System not operational (ground fault, disconnected conductors, etc.) Exceeding inverter voltage limits Use of non DC rated equipment in DC circuits 12 4

5 2017 National Electrical Code Key Articles to Solar PV Article 250 Grounding and Bonding Article 300 Wiring Methods Article 690 Solar Photovoltaic (PV) Systems Article 705 Interconnected Electric Power Production Sources 13 PV Interconnection 14 Article Point of Connection (A) Supply Side (B) Load Side Feeder tap Backfed breaker 15 5

6 Supply Side Connection NEC Article (A) Interconnection on utility side of main service disconnect, (6) Typically on customer side of utility meter Second set of service entrance conductors (Article 230) PV disconnect must service rated NEC Article (C) Wiring methods per Supply Side Connection NEC Article (A) Utility conductors must be on line terminals of disconnect These remain energized when disconnect is opened (turned off) 17 Insulation Piercing Connectors/Taps Source: ILSCO.com Source: ILSCO.com 18 6

7 Insulation Piercing Connectors/Taps Connectors installed outdoors must be rated for the environment. 19 Custom Taps? 20 Load Side Connection NEC Article (B) Key sections include: (B)(2)(1) Feeders (B)(2)(3) Busbar Interconnection 21 7

8 Bus or Conductor Ampere Rating Feeders NEC Article (B)(2)(1) Existing conductors must be increased in size or protected 22 Bus or Conductor Ampere Rating Feeders NEC Article (B)(2)(1) Existing conductors must be increased in size or protected 23 Bus or Conductor Ampere Rating Busbars NEC Article (B)(2)(3)(b) Option (B) 120% Rule 120% of busbar ampacity not less than sum of: Main OCPD 125% of power source output current Main Breaker 100A 125% PV Output 18A Busbar 100A 120% of 100A = 120A Example: Inverter current = 14.4A 14.4A x 125% = 18A Main + PV = 118A 120% Busbar = 120A 118A feeds < 120A bus PV breaker must be at opposite end Do not relocate label required 24 8

9 Breaker Fastening NEC Article (B)(5) Listed plug in type circuit breakers backfed from electric power sources that are listed and identified as interactive shall be permitted to omit the additional fastener normally required by (D) for such applications. 25 PV System Labeling 26 PV System Labeling Key Articles The majority of inspections contain issues labeling Many labeling requirements refer to (B) Field Applied Hazard Markings Words, colors, symbols to meet ANSI Z NOT HAND WRITTEN Sufficient to withstand the environment involved 27 9

10 Labels are faded and not suitable for the environment Labels are faded and not suitable for the environment. Labels are peeling and not suitable for the environment

11 Labels are faded and not suitable for the environment. 31 DC Raceway Label NEC Article (G)(3) and (G)(4) On or in a building Raceways, enclosures, every 10 Minimum 3/8 CAPS on Red 32 Warning labels for DC raceways shall be reflective

12 PV System Disconnect NEC Article (B) 34 PV System Disconnect The Right Way 35 Disconnect Line/Load Energized NEC Article (B) Per (B) 36 12

13 2017 NEC DC Power Source NEC Article MAX SYSTEM DC DC Converter 37 AC Power Source NEC Article Dual Power Sources NEC Article (B)(3) 39 13

14 Do Not Relocate NEC Article (B)(2)(3)(b) Per (B) POWER SOURCE OUTPUT CONNECTION; DO NOT RELOCATE THIS OVERCURRENT DEVICE 40 AC Combiner Panel NEC Article (B)(2)(3)(c) Per (B) THIS EQUIPMENT FED BY MULTIPLE SOURCES. TOTAL RATING OF ALL OVERCURRENT DEVICES, EXCLUDING MAIN SUPPLY OVERCURRENT DEVICE, SHALL NOT EXCEED AMPACITY OF BUSBAR. 41 Service Disconnect Directory NEC Article (B)/ Per (B) 42 14

15 Inverter Output and AC Circuit Disconnecting Means Wiring Methods 43 Disconnection of PV Equipment (Isolating Devices) NEC Article Isolating devices shall be provided to isolate PV modules, ac PC modules, fuses, dc dc converters, inverters, and charge controllers from all conductors that are not solidly grounded 44 Disconnection of PV Equipment Inside the S brand Some inverters only include a DC disconnect

16 Disconnection of PV Equipment (Isolating Devices) NEC Article Isolate equipment from all (power sources) conductors that are not solidly grounded Located either: Within the equipment Within sight and within 10 of equipment An additional AC disconnect may be required if the inverter does not contain one. Outdoor Wiring Methods 47 Type NM Cable NEC Article Article requires conductors to be marked. Prohibited in wet/damp locations Articles (B)(4), (C) Outdoor raceways are wet locations! Article Since 2008 NEC 48 16

17 Outdoor Enclosures Common violations: Not installed so as to prevent moisture from entering or accumulating in accordance with Penetrations not sealed, as required by 300.7(A) Indoor wire connectors, 110.3(B), Enclosures must be installed so as to prevent moisture from entering or accumulating in accordance with Enclosures must be installed so as to prevent moisture from entering or accumulating in accordance with

18 Raceway must be sealed when passing between the interior and exterior of a building per 300.7(A). 52 Bonding the Raceway NEC Article Conductive materials enclosing conductors SHALL BE BONDED! Plastic enclosure outside Metal inside Plastic DC disconnect 53 Bonding Bushings Rated for Outdoor Use? Lay in lug Must be suitable for the environment Outdoor/wet locations (suitable for direct burial) 54 18

19 55 A magnet may be used to determine if a lug does not contain stainless steel (outdoor) hardware. Dissimilar Metals Beyond the lugs Dissimilar metals in contact will result in corrosion. 56 Dissimilar Metals Beyond the lugs Bare copper conductor is corroding because of contact with steel raceway

20 Rapid Shutdown of PV Systems on Buildings 58 Rapid Shutdown of PV Systems on Buildings NEC Article PV system circuits on or in buildings shall include a rapid shutdown function: (A) through (D) 59 About Article Intended to protect first responders Original 2014 proposal: Disconnect power directly under array Module level shutdown 2014 NEC Compromise: Combiner level shutdown 2017 NEC: Back to original, however Source: UL.com 60 20

21 Rapid Shutdown of PV Systems on Buildings NEC Article (A) Controlled Conductors Requirements for controlled conductors shall apply to PV circuits supplied by the PV system (B) Controlled Limits Array Boundary Defined as 1 from array in all directions Rapid Shutdown of PV Systems on Buildings NEC Article (B)(1) Outside the 1 array boundary More than 3 inside a building 62 Rapid Shutdown of PV Systems on Buildings NEC Article (B)(1) Under 30 volts within 30 seconds Measured between: Any 2 conductors Any conductor and ground Source: UL.com 63 21

22 Rapid Shutdown of PV Systems on Buildings NEC Article (B)(2) Effective January 1, 2019 Inside the 1 array boundary, one of following: 1. Array should be listed/field labeled as rapid shutdown 2. Controlled conductors limited to 80 volts within 30 seconds 3. Exception for arrays with no exposed wiring (solar shingles) 64 Rapid Shutdown of PV Systems on Buildings NEC Article (C) Initiation Device Shall be one of following: 1. Service disconnecting means 2. PV system disconnecting means 3. Readily accessible switch that plainly indicates whether it is in the off or on position Not more than 6 disconnects For one family and two family dwellings: Located outside! 65 Rapid Shutdown of PV Systems on Buildings NEC Article (D) Equipment that performs the rapid shutdown shall be listed for providing rapid shutdown protection

23 Rapid Shutdown of PV Systems on Buildings NEC Article (C)(3) Switch label that includes the following: Minimum 3/8 CAPS on Red Required even for microinverters! 67 Rapid Shutdown of PV Systems on Buildings NEC Article Label shall be located on or within 3 of service disconnecting means Shall indicate location of rapid shutdown switches if not at same location (C)(1)(a) Array level shutdown 2019 requirement (C)(1)(b) Traditional shutdown outside array boundary 2014 or 2017 requirement 68 String/Central Inverter 69 23

24 Fuses 690.9(D) requires listed PV overcurrent devices for DC conductors 70 Grounding Electrode System 71 Grounding Electrode System NEC Article (A) Buildings or Structures Supporting a PV Array Building or structure supporting a PV array shall have a grounding electrode system installed in accordance with Part III of Article 250. PV array equipment grounding conductor shall be connected to the grounding electrode system of the building or structure supporting the PV array in accordance with Part VII of Article 250. Sized in accordance with

25 Optional Array Grounding Electrode Conductor NEC Article (B) Ground rod intended for lightning protection Removed in 2011 NEC Back in 2014 NEC Now optional for 2017 NEC, (B) Close as practical to roof mounted arrays Connection per and Building steel may be considered a grounding electrode Permitted to connect to equipment ground Not required to connect to building grounding electrode system Direct connection to array frame or structure 73 Array Grounding/Bonding Wiring Methods Microinverters Modules 74 Equipment Grounding and Bonding NEC Article / A moderate amount of inspections contain issues with Array equipment grounding 75 25

26 Equipment Grounding and Bonding NEC Article / All metal parts likely to become energized Module frames Racking Metal raceways/enclosures Low impedance ground fault current path back to the source or ground detector Inverter or AC panelboard 76 Module Frame Grounding NEC Article Many methods per manufacturer s instructions Lay in lug Must be suitable for the environment in which it is installed Contact with aluminum (usually tin plated copper) Outdoor/wet locations (suitable for direct burial) Listed fitting WEEB Racking Integrated bonding Check the model! Plastic frame No ground required 77 Module Frame Grounding Wrong Lugs (Copper or Not Listed for Outdoor) 78 26

27 Module Frame Grounding Right Fitting, Installed Wrong 79 Module Frame Grounding Integrated Bonding Considerations Some manufacturers: Only midclamps listed to bond module frames, not end clamps READ THE INSTRUCTIONS 80 Module Frame Grounding Integrated Bonding Considerations Other manufacturers: Midclamps and endclamps are listed to bond module frames 81 27

28 Conductor Protection Almost half of inspections contain issues with conductor protection Conductors shall be protected against physical damage (including those beneath array) Articles: (B)(4)(b) (A)(1) 82 PV conductors are not supported under the array. 83 PV conductors are subject to abrasion

29 PV conductors are not supported and leaves and debris are collecting under the array. 85 The Right Way PV output conductors installed in conduit. 86 The Right Way PV output conductors installed in conduit

30 The Right Way PV conductors free from physical damage. 88 PV conductors are properly supported under the array. Upper photo taken from ladder, lower photo taken from ground. 89 Microinverter Mounting Hardware Be aware of microinverter mounting bolt length relative to module frames!! 90 30

31 Readily Accessible Locations NEC Article (A) Ground mount arrays In readily accessible locations, conductors shall be guarded or installed in a raceway 91 PV conductors in readily accessible locations shall be guarded or installed in a raceway. 92 The Right Way Readily accessible PV conductors properly guarded

32 The Right Way Readily accessible PV conductors properly guarded. 94 Module Mounting/Securing More than a quarter of all inspections contain issues with module/racking installation Modules shall be installed in accordance with their installation instructions, as required by NEC Article 110.3(B): Secured at proper locations Utilizing the proper hardware 95 Module Mounting/Securing Proper Locations Limitations for supporting modules in landscape Source: LGSolarUSA.com 96 32

33 Module Mounting/Securing Proper Hardware Endclamps are not one size fits all Midclamps typically can t be installed as endclamps 97 Module Mounting/Securing Rail Length Most manufacturers specify at least ½ of space: Between the end clamp and the end of the rail to Allow for thermal expansion and vibration. 98 Module Mounting/Securing Rail Length 33

34 Module Mounting/Securing Missing Hardware/Improperly Secured 100 Roof Penetrations/Flashing Improper/missing flashing 101 Lag Bolts Lag bolt missed the rafter

35 Lag Bolts Lag bolts missed the rafter. 103 Lag Bolts 104 Thank You Any Questions? Matt Piantedosi Manager of Solar Field Operations cadmusgroup.com Tel:

36 2017 NFPA Conference & Expo CEUs: To receive CEUs for this session, scan your badge at the back of the room before leaving Evaluation: Complete a session evaluation on the mobile app. (Search app store for NFPA 2017 C&E. ) Handouts: Handouts will be available via the mobile app and at nfpa.org/conference Recordings: Audio recordings of all sessions will be available free of charge via NFPA Xchange. 36