Transcript Solar Systems - East Glenville Fire Department

SOLAR SYSTEMS
BASICS
1
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)
2
SOLAR ARRAYS
 There are two common types of solar energy systems;
 thermal systems,
 photovoltaic systems (PV).
 Thermal systems heat water for domestic use, heating,
and recreational use (i.e. hot water, pool heating);
 typically have smaller solar panels than PV
systems.
 Photovoltaic (PV) systems convert sun’s rays into
electricity;
 some PV systems have batteries to store electricity,
 other systems feed unused electric back to the grid.
3
Primary Concerns
 Mounting of the system structurally sound.
 Roof properly weather proofed.
 Electrical equipment correctly specified and
installed according to code.
4
Mounting of System
 Two main types of loads to consider;
• Dead Load
• Wind Load
 Structure must be capable of supporting dead
load and attachment method must be capable of
keeping the PV array on the roof or relevant
structure.
 Most modern truss roofs are capable of
handling the extra dead load provided that the
roof is not masonry.
5
Mounting continued
 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.
6
 What are Solar Cells?
 Thin wafers of silicon;
- similar to computer chips,
- much bigger,
- much cheaper.
7
SOLAR ARRAYS continued
 Silicon is abundant (sand);
- non-toxic, safe
 Light carries energy into cell;
- cells convert sunlight energy into electric
current, they do not store energy.
 Sunlight is the “fuel”.
8
SOLAR ARRAYS continued
 Thermal
system.
9
SOLAR ARRAYS continued
 Photovoltaic
10
Photovoltaic Systems
 Photovoltaic systems have three primary
components;
• Modules
• Inverters
• and Conduit
 Roughly 30x50 inches in area and weighs around
30 lbs.
11
Modules
 A group of modules is called an array.
 Generate electricity from sunlight, 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.
12
Modules
 Most residences have from 15 to 40 panels.
 Will generate anywhere from 2,000 to 5,000 watts
(two to five kilowatts) in optimal sunlight conditions,
at between 120 and 600 volts DC.
 Current ranges between five and nine amps.
13
Inverters and Disconnects
 Modules wired to an inverter, which converts the
DC voltage to AC and then feed the electricity back
into the main power distribution panel.
 The inverter requires AC from the power company,
shutting off the main breakers also shuts down the
inverter.
 Disconnects are often mounted on one or both sides
of the inverter to shut off DC entering and AC leaving
it.
 These disconnects are primarily used by techs to
service the inverter.
14
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.
15
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.
 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.
16
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!!!!!!
17
Photovoltaic
Array
18
Potential Hazards from Solar Systems
Tripping and/or falling hazards while operating on
the roof.
 Earlier roof collapse due to extra weight.
 Hot water scalds with the Thermal system.
 Electric shock.
 Battery hazards.
 Inhalation exposure.
 Access for ventilation.

19
 Inform the IC that a system is present.
 Size-up, identify and validate hazard;
• locate rooftop panels
• obtain system information
• type of system (Thermal or Photovoltaic)
• clarify electrical disconnects
 Stress tactical approach, STAY CLEAR
• shut down as much as possible, “Lock-out”- “Tag-Out”
20
Fireground Tactics
 Leave the scene in a safe condition, i.e., system
damaged during night fire, when exposed to sunlight
begins to generate electric.
 At night, apparatus scene lighting does not produce
enough light to generate an electrical hazard.
 Light from a full moon will not energize the PV cells.
 Lightning is bright enough to create a temporary
surge.
21
Fireground Tactics
 Covering the PV modules with normal FD tarps
WILL NOT block light generation. Only 100% opaque
materials will work.
 Foam cannot effectively block all sunlight.
 If your department carries “noncontact voltage
detectors”, they only detect AC voltage, not DC
voltage.
22
Summation


Daytime = Danger; Nighttime = No Hazard
Components are always HOT! (Daytime = sunlight,
Nighttime = batteries.)
Operate normally, but don’t touch. Treat as
electrically energized.
 Securing the MAIN electrical does not shut down the
PV modules.
 Do not break, remove, or walk on PV modules and
stay away from modules, components and conduit.

23