Eaton has launched an addition to its established SOL30-SAFETY PV fireman's switch and now offers turnkey solutions in the form of ready to install and connect device combinations.
The new SOL30X PV fireman's switch features 2, 3, 4 or 6 fireman's switches - 30 A DC switch disconnectors with a 230 V, 50 Hz undervoltage release - in a common enclosure. The new offering has been introduced to meet customer demand for a solution that is suitable for PV installations consisting of several strings and voltages of up to 1,000 V DC.
In the event of a fire, PV fireman's switches de-energise the cable between the solar modules and the power inverter. This fully removes any danger to the firefighters resulting from live direct current lines. Fireman's switches which can be triggered remotely considerably increase safety when fighting fires in buildings with PV installations.
With an integrated undervoltage trip release, Eaton's PV fireman's switches can be actuated remotely using a "PV emergency off button". Additionally, if the fire services cut the entire building off from the supply network in the event of fire, this automatically triggers the switches and thus cuts the voltage to the PV lines.
In contrast to generator terminal boxes, the individual strings are not connected in parallel but fed separately to the power inverter. This is particularly important for installations with strings which feature different characteristics or are exposed to varying shading conditions.
The undervoltage release bridges momentary power supply interruptions for up to 600 ms, so that over 93% of all brief power failures and voltage drops will not cause a trip, preventing yield losses caused by unintentional release. All fireman's switches feature auxiliary contacts with one N/O and one N/C contact. The N/C contacts in the combinations are factory-wired and connected to the modular terminals. This allows the switch position of the PV fireman's switches to be queried and, for example, displayed with an external indicator lamp or sent as an alarm message by text.
The fireman's switches are available with MC4 solar connectors or metric screw connections. The enclosures feature IP65 protection and are designed for a temperature range of -25°C to +60°C. All generator terminal boxes with a PV fireman's switch are provided with a pressure compensation element in order to prevent the formation of condensation.
Eaton also offers a standards-compliant solution which conforms to the new application guide for the German market, VDE-AR-E 2100-712, valid from May 1, 2013. The guide specifies the measures required to maintain electrical safety in the event of fire-fighting. The technical installation requirements specify equipment for disconnecting at the end of a string / generator or at a building entry point as the top priority. The application guide explicitly forbids the permanent shorting of a string or PV generator.
