SOLAR PANELS

1. SOLAR PANELS Prepared by Thomas Bartsch Chief Fire Inspector (ret) Past Chief of Department Valley Stream, NY

2. These are some of the Applicable Codes and Standards in NY for Solar Panels • National Electric Code (NFPA # 70) for Photovoltaic Systems • Mechanical Code of New York State for Thermal Systems • Plumbing Code of New York State for Thermal Systems • Residential Code of New York State • More restrictive local standards • UL Standard 1703, Flat-plate Photovoltaic Modules and Panels • UL Standard 1741, Standard for Static Inverters, Converters and Controllers for use in Independent Power Systems • IEEE 929-2000, Recommended Practice for Utility Interface of Photovoltaic (PV) Systems (approved in January 2000)

3. Solar CELLS

4. What are Solar Cells? • Thin wafers of silicon; • similar to computer chips, • much bigger, • much cheaper. Solar Cells

5. Solar Cells • Silicon is abundant (sand); • non-toxic, safe • Light carries energy into the cell; • cells convert sunlight energy into electric current, they do not store energy. • Sunlight is the “fuel”.

6. Solar Modules

7. Modules • A group of cells make a module and a group of modules is called an array, • They generate electricity from sunlight, and have no moving parts, • Generally rated at between 125 and 200 watts each and produce between 24 and 48 volts of DC power, • When attached in a series, the voltage increases,

8. Modules • The National Electric Code (NEC) permits; • for one- and two-family dwellings, PV system voltages up to 600 volts (DC), • for multi-family dwellings and other larger buildings, the PV system voltage can be even greater. • Most residences have from 15 to 40 panels, • Residential systems will generate anywhere from 2,000 to 10,000 watts (two to ten kilowatts) in optimal sunlight conditions, at between 120 and 600 volts DC,

9. Modules • There are different types of PV Modules; • laminate/tempered glass- aluminum frame, • flexible laminate module and, • building integrated PV (takes the place of light weight concrete tiles), • solar shingles.

10. Glass with aluminum frame Flexible laminate solar panels

11. Building integrated PV panels Solar shingles

12. Solar Energy Systems

13. Solar Energy Systems • There are two common types of solar energy systems; • Thermal systems, • Photovoltaic systems (PV). • Thermal systems heat water for domestic heating and recreational use (i.e. hot water, pool heating, radiant heating and air collectors); • typically have smaller solar panels than PV systems.

14. Solar Energy Systems • Thermal system.

15. Solar Energy Systems • Photovoltaic (PV) systems convert sun’s rays into electricity; • some PV systems have batteries to store electricity, • other systems feed unused electric back into the grid. • Photovoltaic systems have three primary components; • Modules • Inverters • and the Conduit • Panels are roughly 30x50 inches in area and weigh around 30-35 lbs each,

16. Solar Energy Systems • Photovoltaic

17. There are two types of PV systems: Grid-connected and Off-Grid (remote storage). Grid connected system Most installed PV systems are grid type.

18. Off Grid Photovoltaic System

19. Off Grid Systems • Can have wind-power, water-power and back-up generators to provide energy at night, • Extinguish battery fires with CO2, foam or dry chemical extinguishers, Don’t cut into the batteries, • Keep in mind that if corrosive fumes come in contact with certain metals, they will produce toxic chemicals and explosive gases, wear PPE & SCBA, • Careful with metal tools around batteries.

20. Mounting of THE System

21. Primary Concerns • That the mounting is structurally sound, • That the roof is properly weather proofed, • That electrical equipment is correctly installed according to applicable codes, • And there are Two main types of loads to consider; • Dead Load • Wind Load

22. Mounting of Systems • The roof structure must be capable of supporting the dead load, • Most modern truss roofs are capable of handling the extra dead load provided that the roof is not masonry, • Masonry roofs often require a structural analysis or removing the existing product and replace it with composite in the area of the PV array, • Attachment method must be capable of keeping the PV array on the roof or relevant structure.

23. Mounting of Systems • Solar panels are installed either by; • Stand mounting, • Flush mounting or, • Building Integrated arrays.

24. Mounting of Systems • Stand Mounts; • the universal mounting system, used for ground and rooftop installations, • a grid-like system of supports of aluminum or steel that are affixed directly to roof joists, • or use non-penetrating concrete blocks,

25. Mounting of Systems • Flush Mounting; • raised several inches to allow air circulation, • brackets are attached to the roof, • may be hard to see during the night,

26. Mounting of Systems • Building Integrated Arrays; • serve as a structural element, • does reduce added weight, • photovoltaic shingles could be subject to high winds, • very difficult to see during the night or from the ground, Pre-Planning is very important!

27. Mounting of System Examples of Building Integrated Systems

28. Solar panel Inverters, Disconnects & Labels

29. Inverters and Disconnects • Modules are wired to an inverter, which converts the DC voltage to AC voltage and then feeds the electricity back into the main power distribution panel, • The inverter requires AC from the power company, shutting off the main electrical breakers also shuts down the inverter, • On new construction, inverters will most likely be installed within the building,

30. Inverters and Disconnects • Inverter can be mounted inside or outside of the building, • On Grid systems, inverter typically located near main electrical panel, • Off-Grid system, inverter either inside or outside of building, • Inverter may be found in a separate building that contains a generator or battery storage, • Also the inverter may be near devices or appliances the panels provide power to,

31. Inverters and Disconnects • Disconnects are often mounted on the inverter to shut off DC entering and AC leaving it, • These disconnects are primarily used by techs to service the inverter,

32. Inverters and Disconnects • DC disconnect does not shut off power in the DC conduit, it just keeps it from entering the inverter, • DC conduit is still live between the array and the inverter DC disconnect, • There is no rooftop disconnect to kill the DC power in the conduit.

33. Solar Inverter • PV arrays use an inverter to convert the DC power produced by the modules into AC, • For safety reasons a circuit breaker is provided both on the AC and DC side to enable maintenance.

34. Micro Inverter is connected at each module

35. Labels • Labels on the main service panel will indicate the PV system presence, • Labeling may be outside or inside of the main panel, • Look for the dedicated breaker for the inverter, it may be labeled “Solar Disconnect” or some variation thereof, • This breaker may be in a sub-panel, but there will always be a label on the main electrical panel stating presence of a second generating source on site,

36. Labels • Labels may be the only identifiers you might see, as the array may not be visible and the inverter may be in the fire. • LOOK FOR LABELS!!!!!!

37. LOOK FOR LABELS

38. Fire Department OPERATIONS at solar arrays

39. Fire Operations • PV systems can impact our FD operations and may also be part of the fire problem, • There is no single point of disconnect unlike standard electrical or gas service installations, • Severely damaged PV arrays are capable of hazardous conditions up to electrocution and can create unexpected electric paths, (i.e., metal roofs, gutters and array components),

40. Fire Operations • The black cable connecting each panel carries voltage and increases as it goes from panel to panel, “DON’T CUT THE CABLE OR REMOVE PANELS”, • Do not cut into or walk across the PV modules or arrays, • Breaking protective glass could release all inherent energy in entire PV system,

41. Fire Operations • Always wear PPE and SCBA, • FF gloves and boots offer limited protection and are not be equal to electrical PPE, • Size-up; • locate if panels are present, • get system information, • what type of system (Thermal or Photovoltaic), • locate electrical disconnects,

42. Size Up This array can be seen from the street upon arrival This light source might help you see the array at night

43. Size Up You might see this one while doing your 360 What about this one at night?

44. Think you will see this one at night while doing your 360? Size Up Conduit coming from the roof could be a clue, look for it.

45. Fire Operations • Inform the IC that a system is present, the IC must relay this info to the responding units, • Use a STAY CLEAR approach; • shut down as much as possible, “Lock-out”- “Tag-Out” • disconnect at the inverter, battery controller, and the battery bank as an extra measure of safety, • Remember PV Panels are 120 volts - 600 volts DC,

46. Usage of Tarps to cover the solar panels

47. Tarps • If operations require attempting to block light to the PV to protect FF, a tarp might be used, • Effectiveness of tarps to interrupt power generation varies with the type of tarp material, • Underwriters Laboratories (UL) research,1 have shown heavy, densely woven fabric & dark black 4 mil plastic reduce the power to near zero, 1 “Firefighter Safety and Photovoltaic Installations Research Project, Issue date 11/29/2011”

48. Tarps Research conducted by UL1, using only a single tarp layer, to block illumination to the panels, has shown: Green Canvas Salvage Cover, (test results were 3.2 open circuit volts and 0 short circuit amps) were SAFE to use, Heavy Duty Red Vinyl Salvage Cover, (test results were 124 open circuit volts and 1.8 short circuit amps) was an electrocution hazard,

49. Tarps Blue plastic 5.1 mil all purpose tarp, (test results were 126 open circuit volts and 2.1 short circuit amps) was an electrocution hazard, Black 4 mil plastic film, (test results were 33 open circuit volts and 0 short circuit amps) was deemed SAFE to use.

50. Tarps • If light can be seen through the tarp, it should NOT be used, • A WET tarp may become energized if it contacts damaged PV equipment and conduct dangerous current, • The tarp must be secured down on all sides, • RISKvsREWARD, is it worth the risk to cover arrays, especially damaged arrays, to accomplish venting, overhaul, etc.???