Fire and lightning protection
In order to adhere to fire protection in photovoltaic installations, a variety of measures are necessary. The following points outline some of those measures.
- If lightning protection is already installed, or depending on the risk assessment, incorporation of the lightning/overvoltage protection is required.
- The selection of components with regard to maximum temperatures in and around the distribution boxes must be taken into account.
- Quality control of the electrical connections is important. (Transformer) fires frequently occur due to arcs on defective cable inlets.
- The selection of how the rectifier and inverter cables are to be laid must be accounted for. (Example: a cable in the ground has a lower current load than one laid on a cable conduit.)
- The distances of the inverters from the sides and adjoining building parts is important.
- Additional requirements, such as DIN 182234, must be fulfilled for industrial and functional buildings.
- No fire areas may be built over. Firewalls are frequently built over, especially in elevated roof systems.
- Care must be taken with the selection of fuses. The manufacturers’ information must be noted with a parallel connection of several strings.
- Direct current wiring must be permanently adapted to weather conditions. Extremely high temperatures occur with arcs.
- Installing a fireman’s switch (photovoltaics) is recommended. The codes of practice (requirements for installation in the DC area of a PV installation) VDE AR E 2100-712 are currently being laid out.
- Checking the photovoltaic installation for the existing lightning protection in accordance with DINVDE 0185 (DIN EN 62305-3 VDE 0185-305-3, Supplement 5)
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Photovoltaic fireman's switch
Laying of cables with fire protection covering over a firewall (source: OBO Bettermann)
Inadmissible laying of cables over a firewall (source: VGH)
750V protection equipment