Grounding Fault – and Short-Circuit-Proof Wiring

The use of double-insulated cables and wires automatically provides grounding fault – and short-circuit – proof wiring, which should be used in PV installations without fail. If double-insulated cables are unavailable, or if an extra measure of safety is desired, such wiring can be realized by installing positive and negative cables in separate insulating raceways.

Cross Section of Special Solar Cables (Radox 125)

double insulated cable 2H0 mm2 for DC main cables

Подпись: (with shielding 10 mm2)Подпись: shielding 10 mm2 CuПодпись:image481special wires (2.5mm2 – 6mm2) for string wiring

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copper

conductors

insulation (Radox 125, resistant against UV and temperatures up to 125°C)

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Figure 4.77 Special solar wires and shielded DC cables for optimal PV system lightning protection. Double-insulated cables should be designated as such using two different colours, as is done for solar wires (Photo: Huber+Suhner AG)

However, such raceways are more expensive and electrically less desirable when it comes to protecting a PV installation against lightning strikes in close proximity to the installation. The ideal lightning protection solution is the use of continuous metal raceways containing cables with dual insulation. If separate metal raceways are used for the positive and negative cables, it is essential that the two ends of the raceways be interconnected. This also applies to shielding for double-insulated shielded single conductors.

Updated: August 7, 2015 — 12:31 am