Solar Panels

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

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Solar CELLS
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Solar Cells

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

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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.

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Solar Modules
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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,

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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,

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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.

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Glass with aluminum frame
Flexible laminate solar panels
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Building integrated PV panels
Solar shingles
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Solar Energy Systems
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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.

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Solar Energy Systems

• Thermal system.

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Solar Energy Systems

• Photovoltaic (PV) systems convert suns 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,

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Solar Energy Systems

• Photovoltaic

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There are two types of PV systems Grid-connected
and Off-Grid (remote storage).
Grid connected system
Most installed PV systems are grid type.
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Off Grid Photovoltaic System
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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, Dont 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.

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Mounting of THE System
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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

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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.

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Mounting of Systems

• Solar panels are installed either by
• Stand mounting,
• Flush mounting or,
• Building Integrated arrays.

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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,

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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,

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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!

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Mounting of System
Examples of Building Integrated Systems
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Solar panel Inverters, Disconnects Labels
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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,

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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,

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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,

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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.

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• 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.

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Micro Inverter is connected at each module
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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,

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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!!!!!!

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LOOK FOR LABELS
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Fire Department OPERATIONS at solar arrays
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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),

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Fire Operations

• The black cable connecting each panel carries
  voltage and increases as it goes from panel to
  panel, DONT 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,

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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,

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Size Up
This array can be seen from the street upon
arrival
This light source might help you see the array at
night
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Size Up
You might see this one while doing your 360
What about this one at night?
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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.
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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,

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Usage of Tarps to cover the solar panels
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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
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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,
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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.
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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,
• RISK vs REWARD, is it worth the risk to cover
  arrays, especially damaged arrays, to accomplish
  venting, overhaul, etc.???

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Water and firefighting foam use on solar arrays
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Water Foam

• Water conductivity, voltage, distance and spray
  pattern effects electrical shock hazard,
• UL1 research has shown that the use a fog
  pattern with a min of 10 degree cone angle, with
  a distance of 5 ft from a 1000 vDC, detected no
  current leakage,
• A smooth bore nozzle required a 20 ft distance
  with the same 1000 vDC,
• Because of its high conductivity, salt water
  should NOT be used on live electrical equipment,

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Water Foam

• Firefighting foams should NOT be relied on to
  block light on solar panels, as they proved to be
  ineffective,
• Outdoor solar electric boxes are not water
  resistant to fire streams, they will collect
  water and present an electric shock,
• No matter what the system, REMEMBER, applying
  water directly to any energized electrical
  equipment endangers FF to shock, turn off the
  main breaker at the electric panel.

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Scene lighting
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Scene Lighting

• FD flood light trucks ARE bright enough to
  generate electricity, (UL research1)
• Light from a fire, as far away as 75 feet was
  able to produce current, (UL research1)
• Light from a full moon will not energize the PV
  cells,
• Lightning is bright enough to create a temporary
  surge,

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Scene Lighting
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Scene Lighting

• At night, apparatus roof rack lighting does not
  produce enough light to generate an electrical
  hazard,
• If your department carries non-contact voltage
  detectors, they only detect AC voltage, not DC
  voltage.

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Get the roof!!
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Get The Roof
General

• Remember, solar panels can impact our
  firefighting operations, especially PV systems,
• Proximity to any fire involving photovoltaic
  system also brings with it an increased risk of
  inhaling toxic vapors, use your SCBA,
• Should array become involved in a roof fire, use
  fog pattern, min 10 degrees,

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Get The Roof
Safety

• Shock is the PRIMARY firefighter danger,
• Momentary contact with low DC voltages may
  produce
• Continuous Shock,
• Thermal Injury,
• Ventricular Fibrillation,
• Tripping and/or falling over raceway, etc.,

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Get The Roof
Safety

• Possible earlier roof collapse due to extra
  weight, especially under a heavy fire load,
• Arrays can accumulate snow debris, added
  weight,
• Hot water scalds with the Thermal system,
• Electric shock, due to intentionally or
  inadvertently cutting into or through PV
  conductors, or raceways containing live PV
  conductors,

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Get The Roof
Safety

• The NEC permits
• single conductor PV wire to be exposed in
  non-accessible outdoor locations, such as
  rooftops and ground mounted arrays,
• when PV circuits are run inside a building, the
  conductors must be contained in a metal raceway,
• when PV wires are run beneath a roof, they shall
  not be installed within 10 inches of the roof
  decking or sheathing, except where directly below
  the roof surface covered by PV modules and
  associated equipment,

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Get The Roof
Safety

• The 10 inch requirement is to prevent accidental
  damage from saws used by firefighters during roof
  ventilation,
• It is important to also note that this
  requirement is new in the 2011 version of the
  NEC, and older installations may not have
  complied with this new requirement,

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Get The Roof
Safety

• Inhalation exposure, the manufacturing process
  includes the use of many hazardous chemicals,
• Access for ventilation,

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Get The Roof
Operations

• Ventilate at the highest point over the fire
  without cutting through the PV array,
• Flat roofs with complete PV coverage
• horizontal ventilation with fog spray and/or
  Positive Pressure fan ventilation,
• Fire and extreme heat will also affect the
  structure of the module. The high temperatures
  might cause the metal to warp and the modules to
  come loose from their anchor points, dangle or
  fall,

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Get The Roof
Operations

• Fire could cause damage to the wiring insulation
  and melt the aluminum mounting rail, resulting in
  possible loss of ground continuity, energizing
  the module frame and mounting rail,
• Leave the scene in a safe condition, i.e., system
  damaged during a night fire, when exposed to
  sunlight, it begins to generate electric,

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Now add metal roofing to the hazard
Get The Roof
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Cut a hole, dont trip and dont inadvertently
pierce the panels, OK!
Get The Roof
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There is no venting this roof with this
installation!
Get The Roof
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SCBA
Get The Roof
Use a minimum 10 degree fog pattern
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Not much room to vertical vent here!
Get The Roof
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Get The Roof
Skylights, scuttles, smokes vents?
Positive pressure fans and/or fog nozzle to vent?
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Get The Roof
Where are you going to perform roof ventilation
on this installation?
Hope the other side is clear!
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Summary

• Pre-Planning is essential,
• If a system is present, notify IC and responding
  units,
• When a sufficient light source is present,
  panels are energized,
• Scene flood lighting can create dangerous levels
  of electricity,

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Summary

• Dont try to unplug or walk on the panels,
• Dont intentionally break the panels or cut the
  conduit,
• Contact with damaged systems are dangerous, even
  if the fire is out - stay away,
• PV systems are the only electrical system that
  cannot be turned off by untrained personnel.

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Thank YouQuestions?