FIREFIGHTER SAFETY SWITCH
USER INSTRUCTIONS
Intended use
The Firefighter safety switch (FSS) has been especially developed as an additional device for direct
current (DC) photovoltaic installations. The motor driven DC disconnect switch is made to withstand a
continuous current flow at a maximum of 25A at a string voltage of 750 VDC, or 16A at a string voltage
of 1000 VDC.The DC disconnect switch is used to disconnect the connected strings of the installation
in case of an emergency situation, either under load or no-load situations. Such an emergency situation
could be in case of fire.
NOTE: The switch enclosure and/or the operating panel enclosure may not be installed in direct sunlight
or be in direct contact with (continuous) ingress water.
Firefighter Safety Switch
The switch enclosure needs to
be placed as close to the string
entry of the building as possible
and may be placed in outdoor
situations when needed. Due
to its enclosure, the switch is
protected against external
influences like dust and
moisture. The whole set-up
is conforms to IP65. This will
make it resistant to direct water
jets from all directions.
Operating Panel
The firefighter must be able to safely
disconnect the photovoltaic installation
which is in operation and make sure
the installation is completely switched
off before proceeding further. To aid the
firefighters, the operating panel must
be used in case of emergency to switch
off the installation. The operating panel
therefore needs to be placed in an easy
to access location. The operating panel
must be visible for fire fighters so they
can see the status and instantly act in
case of an emergency.
Junction Box (optional)
Combining individual string
cables into lead cables to the
inverter. Can optionally include
fuses, overvoltage protection
and arc fault detection.
Inverter
String or lead cables join into the inverter
which provides the connection to the external
power grid.
External fire alarm (optional)
An external alarm can also be
connected to the Operating
Panel and thereby activate
the disconnection of the safety
switches.
Operation
Powering up:
When all connections are made according to the specifications in this manual, the operating panel will
show a green LED indicating that all connected switches are in a disconnected state OFF. This indicates
a safe situation for the firefighter. When you release the key operated push button, the system will send
commands to turn all connected switches ON. If this is working correctly, the red (or white) LED will blink
momentarily and burn continuously when the command is executed. The red (or white) LED indicates that
the switches are ON and thus an unsafe situation for the fire fighters.
NOTE: The key used to turn the switches ON must be kept separate from the operating panel and only
authorised personnel are allowed to use this.
Normal operation:
Pressing the push button will instruct the switches to break the connection between solar panels and the
inverter. Releasing the push button with the key will instruct the connected switches to make the
connection between solar panels and the inverter.
Special operation:
Power down:
If there is going to be a power down situation, the operating panel will no longer provide the
signal commands to the connected switches after approximately 10-15 seconds.
Connection loss:
If one of the connected switches looses contact with the operating panel, this switch will also
break the connection between the solar panels and the inverter.
Testing the system:
It is considered mandatory to test the firefighter safety switches at least once every three
months. This is to ensure the system is still fully functional.
Fault situation:
When the operating panel cannot determine that all switches are in the same position or if not all switches
have changed position within 15 seconds, both the LED’s will blink and a buzzer will sound until a reset
has been performed.
The switches need to be checked and all placed in the same position to ensure the operating panel can
be reset. The fault mode can be reset by pressing the push button and releasing it with the key 2 times
within 3 seconds. This will reset the electronics and start the state check of all connected switches.
Checklist Fault situation:
• Check Voltage at the switch; this must be 24VDC (± 5%)
• Check switch positions; these must ALL be ON or OFF
• Check wiring of all switches; these must be according to the “Wiring Schematics” on pages 26 and 27
• Check wiring of the Operating Panel
• Check Voltage and Current of the power supply: see “Technical Data” on page 7
If a fault situation keeps occurring please contact Santon for more information:
14
15
EN
