Rooftop systems: Buildings without external lightning protection

What happens if a photovoltaic system is newly or subsequently installed … does the new system require lightning protection measures for the entire building?

Normative requirements and notes:

If no external lightning protection system is installed (and this is not required according to the risk analysis in conformity with IEC 62305-2), Supplement 5 to DIN EN 62305-3 recommends to use a type 2 surge protective device on the d.c. and a.c. side to protect PV systems from inductive and conducted interference. Moreover, the data interfaces are to be protected by means of adequate surge arresters.

Comprehensive protection

The d.c. and a.c. side as well as the data interfaces are protected and equipotential bonding is established to ensure comprehensive protection of a rooftop system on a building without lightning protection system.

 

Sample application:

Sample application for Buildings without external lightning protection

A - DEHNshield® Basic

Main distribution board: Combined arrester mounted directly at the entrance point into the building. It protects the electrical installations in the immediate vicinity.

Product details

A - DEHNguard® modular

Alternatively: Surge arrester that protects against overvoltages from inductive couplings by distant lightning strikes and from switching overvoltages. It must be installed downstream of the electricity meter which means that it does not protect the Smart Meter and Smart Meter Gateway.

Product details

B - DEHNbox TC 180

Internet, telephone, broadband: Combined arrester that offers protection in the event of lightning strikes and overvoltages. It secures telephone and DSL connections. Its compact design makes it quick to install in new buildings and easy to retrofit in existing buildings.

Product details

C - DEHNguard® M YPV

PV-installation: Type 2 arrester specially designed for application in PV systems. Protects the DC side of the inverter against surges from inductive couplings. If there is more than 10 metres of cable between the PV system and the inverter, a further arrester is necessary in the roof area.

Product details

C - DEHNcube YPV SCI 1000

Alternatively: Type 2 arrester that provides comprehensive protection for a PV system in an enclosure. It is mounted directly upstream of the inverter and is available in two versions, 1 MPPT and 2 MPPT. If there is more than 10 metres of cable between the PV system and the inverter, a further arrester is necessary in the roof area.

Product details

D - DEHNguard® M

a.c. side: Surge arrester that protects against overvoltages from inductive couplings by distant lightning strikes and from switching overvoltages. If there is more than 10 metres of cable between the service entrance box and the inverter, a further type 2 surge arrester is required at the inverter.

Product details

E - UNI earthing clamps/saddle clamps

Equipotential bonding: Clamps suitable for integrating the mounting systems of PV installations in the functional equipotential bonding / the functional earthing or the lightning equipotential bonding.

Product details