Cables & Wiring
To make efficient use of the precious electricity made by either wind generators or solar modules and stored in batteries, it is most important to choose cables and fittings carefully. The right cables of the correct cross-section should be used to ensure safety, reliability and to minimise voltage drop and energy losses.
Larger wire sizes are required in lower voltage DC systems than in standard AC systems.
For battery based PV systems, with average mechanical stresses and use in the open the following flexible 2 core cables are very suitable. Their H07RN-F rating means they are sunlight UV, ozone, temperature and weather resistant. Rubber insulation, black outer, blue/brown cores.
For higher voltage DC systems (such as grid connect PV arrays) double insulated single core Solar cable should be used. See MultiContact.
Very high currents can flow in cables connecting inverter to the batteries and between the batteries. Cables must be adequately sized to suit the maximum current drawn by the inverter. Low resistance links and tight connections are essential to maintain even use of a battery bank.
In order to minimise the voltage drop between battery and inverter, and so maintain inverter efficiency, cables should be kept as short as possible and be sufficiently sized.
In operating a wind or solar system, there is a necessity for trouble-free operation. There are many options for system control and monitoring. Wireless communication using Bluetooth or radio may be possible but often, especially where the data is of high value a wired solution may be best. In this case it is important to use the proper cables for reliable data communication.
The cables used for wiring the DC section of a grid-connected wind or PV system need to be selected to ensure that they can withstand the environmental, voltage and current conditions at which they may be expected to operate, including the heating effects of both current and sun.