AUC 351 PHOTOVOLTAIC (SOLAR PANEL) ELECTRICAL SYSTEMS

Question 1

Both residential and commercial solar photovoltaic systems operate on the same principle
and both pose similar dangers, the greatest hazard of which is

Answer 1

Direct Current (DC) shock.
Sec 2.1

Question 2

Can PV systems produce electricity on cloudy days ? How about at night ?

Answer 2

PV systems can still produce electricity on cloudy days, but not as
much as they do on sunny days. PV systems do not produce electricity at night.
Sec 2.2

Question 3

Solar Cells (40) can be interconnected to create modules. Modules can be interconnected to create ?

Answer 3

A PV ARRAY

Sec 2.3

Question 4

Most PV arrays use __________ to convert the DC power produced into alternating current (AC) that can tie into existing infrastructure to power
lights and other electrical loads.

Answer 4

An Inverter !

Sec 3.3

Question 5

A typical PV module
consists of a protective weatherproof enclosure for the cells and electric wiring needed to
connect the module with the rest of the system. Sealed junction (combiner) boxes
containing fuses or circuit breakers protect the connections.
True or False

Answer 5

TRUE!

Sec 3.2

Question 6

These systems operate independent of the utility grid. These type systems are
comprised of PV arrays, a charge controller and storage batteries to supply power to DC
loads.

Answer 6

Stand-alone PV system

Sec 4.1

Question 7

These systems utilize grid-tie inverters that are integrated with the public
utility. These type inverters synchronize the solar energy from the photovoltaic array that
it converts from DC to AC to the primary electrical panel of the building. The power
may then be used by loads within the building or __________ ??

Answer 7

On-grid connected systems

It may flow out to the utility.
Sec 4.2

Question 8

Does an On grid system use batteries ?

Answer 8

YES!!
Batteries may also be used for these
type systems to store power where the consumer wants to have electricity in the event of
a blackout.
Sec 4.2

Question 9

When a PV array covers a large
portion of the roof it leaves little room for members to maneuver and operate. That being said
Lt TARD is on a roof with solar panels. He has his Roof FF stand directly on the modules and has him cut every wire in sight.
Agree or Disagree

Answer 9

DISAGREE!!
Firefighters must avoid walking on modules since this can expose them to electric shock.
Additionally, firefighters must never cut any wires associated with a PV array.
Sec 6.1

Question 10

Does Shutting off power at the main electrical panel ensure that all power to the building has been removed. What about the opening of isolation switches ?

Answer 10

Shutting off power at the main electrical panel, does not ensure
that all power to the building has been removed.

This holds true for opening PV
disconnect (isolation) switches
Sec 6.1

Question 11

Where can isolation Switches be found ?

Answer 11

Switches can be located: 
on the roof,
next to the main electrical panel, 
adjacent to the inverter, 
nearby the charge controller,
in the battery bank area, 
and outside the building.
Sec 6.1

Question 12

When exposed to sunlight, PV arrays will continue to generate electricity and energize
conduit and components up to the _____ ??

Answer 12

inverter

Sec 6.1

Question 13

What can be shut down in a Solar power system that will ensure power does not enter the building from the PV array ?

Answer 13

INVERTER!!
Shut-off electrical power to the inverter to ensure power does not enter the
building from the PV array conduit, batteries, or back-up generator. Be aware that
inverters do have capacitors which store energy.
Sec 6.1

NOTE: The energy within the capacitors, however, will discharge soon after the power to the
inverter is disconnected

Question 14

The use of rooftop disconnects should not be
relied upon since they are mainly installed in order to perform maintenance on the
system.
True or False

Answer 14

True!

Sec 6.1

Question 15

At fires with a Solar panel system on roof. What is the primary focus of ladder companies when trying to vent ?

Answer 15

The opening/removal of skylights and scuttles as well as HORIZONTAL Ventilation should be the
prime focus of ladder company operations. All ventilation must be coordinated by
members both inside and outside the building in order to avoid a backdraft and flashover.
Sec 6.2

Question 16

Firefighters discovering PV arrays at fires and emergencies should immediately notify who ?
If the system is involved in fire ! who is notified ?

Answer 16

Company Officer and the IC for subsequent relay to all operating members.
They should also inform the IC if the PV system is involved in fire and if it is going to
negatively impact vertical ventilation operations.
Sec 6.3

Question 17

At top floor/cockloft fires cutting the
roof must be limited to areas that are clear of PV arrays and other components, while
constantly evaluating whether the venting operation will pull the fire into uninvolved
areas of the building. Ladder company efforts INSIDE the building should be directed
toward

Answer 17

opening ceilings to define the boundaries of the fire.

Sec 6.3

Question 18

When can Ventilation fans be used to remove smoke and heat from the top floor of a building with PV arrays on roof ?
The IC should Delay Overhaul till when ?

Answer 18

Once the fire
has been extinguished.
The Incident Commander (IC) should delay overhaul until there
is confirmation that that the PV system has been shutdown.
Sec 6.3

Question 19

Using water on energized PV system components is a decision that should only be made
by ?

Answer 19

The IC after careful size-up

Sec 6.4

Question 20

As a Lt and after IC approval You direct your members to apply water directly on the energized PV components. How should this be done ?
Can foam be used ?

Answer 20

Hose streams should not be applied directly onto
energized PV system components. A fog nozzle, utilized from a distance, and set at a 30
degree spray pattern.
Straight steams or foam should not be used since
they are excellent conductors
Sec 6.4

Question 21

The removal of modules by firefighters is NOT an option.

Answer 21

Again…….The removal of modules by firefighters is NOT an option.
Sec 6.4

Question 22

Incipient fires involving PV systems can be extinguished using what ?
Where can foam be used ?

Answer 22

Class C (dry chemical) portable fire extinguishers.
Sec 6.4
The use of dry
chemical or FOAM extinguishing agents has proven to be effective on battery fires.
Sec 6.7

Question 23

Fires involving PV systems should be extinguished with the same care as any other type
of electrical equipment. De-energize all of the PV components along with any other
utility supplied electrical power serving the building.
Agree or Disagree

Answer 23

AGREE!!

Sec 6.4

Question 24

PV panels produce DC power. If sunlight strikes them, they will produce electricity.
Unless there is a __________ on the PV array itself, the wires running from the
array to the power distribution system should always be considered live.

Answer 24

disconnect switch

Sec 7

Question 25

Utilizing disconnects ahead of or after the inverter still does not eliminate the electric
current coming from the PV array.
True or False

Answer 25

TRUE!!

Sec 7

Question 26

Is it a good idea to open up combiner boxes in an attempt to shut down the PV array ?

Answer 26

NEGATIVE ! BAD IDEA!!
Combiner boxes should not be opened by firefighters in an attempt to shutdown the PV array.
Sec 7

Question 27

PV systems do not produce electricity at night. However, what can still charge this system ?

Answer 27

Lightning flashes occurring at
night can energize the PV System.
Sec 7