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1. Introduction
In most photovoltaic systems, the DC isolator is integrated into the DC/AC power inverter. After
switching off the DC isolator, the cables between the DC solar modules and DC/AC power inverter
running through the building are still subject to up to 1000 Vdc. In the event of a fire, firefighters are
exposed to a very serious source of potential danger. The S-Box Plus provides the solution to this
problem. It directly disconnects the DC current in close proximity to the solar modules and creates a
safer situation for firefighters.
Basic Features:
·AC power shut down=automatic DC power shut down
·Auto reset when AC power is back=DC power is back
·Easy to install
2. System Advantages
2.1 Easy installation
S-Box Plus can be installed without disassembling the shell.
2.2 Gain valuable time in case of a fire
S-Box Plus works according to standard international firefighter routines, resulting in valuable time lost
in AC power is shut down, S-Box Plus will automatically switch off and isolate DC cables running
between the PV modules and the inverter. Firefighters only have to follow their regular routine and do
not have to waste valuable time eliminating the risk of DC power still present at these cables. In case
the AC power is not shut down and the temperature reaches 70°C at the S-Box Plus unit it will
automatically shut down the DC power as extra safety system.
2.3 Completely isolate PV modules
S-Box Plus is powered by a motorized X-type switch and can therefore be located directly at the PV
modules. This minimizes the amount of cabling with dangerous high voltage and leads to a completely
powerless situation in the house, maximizing safety when needed.
2.4 Auto reset
A power down situation can occur at any time and for many reasons. S-Box Plus has an auto reset
function. S-Box Plus automatically switches off if the regular AC power is down for more than 6 sec and
automatically switches on when the regular AC power is on again. No manual reset is necessary every
time the power has been down! After check of the safety situation and when the AC main power is
reconnected automatically the S-Box Plus will switch on the DC power.
2.5 For use in industrial and residential photovoltaic installations
By using this standard concept unit for either 1 or 2 strings it is possible to combine unlimited number of
units to fix every size of installation. As option it is possible to connect all units to the same AC source in
order to create a separate DC on-off operation by switching this specific AC source on-off that will
operate all units at the same time. Again, reset is done automatically AC on = DC on, AC off = DC off.
These units can be easily retrofitted to existing or new installations.
2.6 Indication of DC switch status
S-Box Plus integrated with status indicator for customers to confirm the switch status.
2.7 RS485
The RS485 interface on the S-Box Plus can provide grid voltage temperature, switching status and other
information via external communication.
