Non-compliance with the separation distance can lead to flashovers from the external lightning protection system conductors to electrical and metal installations inside of the structure.
However, too little importance is often attached to electrical isolation in external lightning protection systems. Consequently, the air-termination system of the external lightning protection system is installed in the form of meshes, e.g. on extended facilities such as logistics centres, high-bay warehouses or production buildings without the necessary separation distance to metal components and electrical systems underneath.

The roof conductor holders DEHNiso RCH have been developed for an easy and practical realisation of electrical isolation in external lightning protection systems. They consist of a glass-fibre reinforced plastic (GRP) bar with plastic conductor holder and a concrete block with plastic base plate.

The spacing between the roof conductor holders (mid to mid of GRP bar) is max. 1.0 m each.
The roof conductor holders are dimensioned according to Eurocode 1 (DIN EN 1991-1-4 + DIN EN 1991-1-4/NA) provided that the specified distance of ≤ 1.0 m is complied with.
This system is compatible with GRP/Al air-termination rods, if protected volumes are needed, e.g. for roof-mounted structures.

Spacer bar made of glass-fibre reinforced plastic (GRP) Ø10 mm, UV-stabilised, light grey colour
The material factor k_m = 0.7 is used to determine the separation distance (length of spacer bar).
The insulating clearance of 220/360 mm in length thus equates to a separation distance of 150/250 mm (in air) or 300/500 mm (solid building material).

The DEHNiso roof conductor holders are tested in line with DIN/IEC TS 62561-8.