Fire protection for photovoltaic systems
Combustible cables may not be run over firewalls without fire protection measures. This is because, in the event of fire, they would spread the fire to the neighbouring roof area. However, individual cases are possible, in which the routing of combustible cables over firewalls cannot be avoided. In these cases, the cables must always be routed in a protected manner. OBO can offer two different solutions for this:
▪ Routing of the PV cables in extremely robust, form-stable stainless steel ducts PYROLINE® PLMR
▪ The wrapping of the cable bundles with the flexible and weatherproof cable bandage PYROWRAP® Wet FSB-WB
When there is a fire, the substances forming an insulation layer, which are contained in both solutions, foam up and prevent the spread of fire via the PV cables. In this case, the transmission of smoke is non-critical, as the volume of fire smoke can be passed to the ambient air without hindrance.
Insulated lightning protection under WDVS If isCon® cables are routed within a composite heat insulation system (WDVS), then they may penetrate so-called fire locks made of non-combustible substances. If there is a fire, the fire locks may even fail. Here, the PYROWRAP® Wet FSB-WB cable bandage is again used, which prevents the spread of the fire. Whilst the insulation burns and openings are created, the insulation layer creator foams them up again. This safely prevents a chimney effect via the isCon® conductor.
Routing PV cables within buildings
In some cases, the cables carrying direct current must still be routed through the building, up to the inverter. If the installations are in escape and rescue routes, then the PV DC cables must be routed in encapsulated form.
The OBO PYROLINE® Sun PV fire protection ductis suitable for this. The installation duct, made of fibre glass-reinforced lightweight concrete and with a non-conductive surface, ensures protection against dangerous contact voltages. In addition, it fulfils the requirements of the application rule VDE AR-N-E-2100-712 for fireproof and contact-proof installations. This also offers additional protection for the rescue services against electric shocks during extinguishing work. A further advantage: This means that the duct can be routed in exterior areas. It is particularly suitable for the later encasing of previously installed DC cables, as it can be adjusted flexible to the cable routes. The installation of the duct can take place directly on the wall or ceiling. The appropriate connection armatures mean that suspended mounting is also possible.
In addition, the fire protection ducts fulfil the requirements of the application rule VDE AR-N-E-2100-712 for fireproof and contact-proof installations (Sections 6.2 and 6.4). This also offers additional protection for the rescue services against electric shocks during extinguishing work.
Protection through organisational measures
At the transition point of the electrical system, e.g. house connection box or on the main distribution, VDE 0100-712 requires the attachment of the standardised information sign, also known as the fire brigade sign. The fire brigade can recognise the PV system through the identification. Accordingly, the extinguishing measures are then carried out whilst maintaining the safety spacings according to DIN VDE 0312 – Firefighting and technical assistance with electrical systems.
