I have to wire solar DC photovoltaic panels and have always used at least an 8 gauge wire. Recently, I installed a solar electric fence and they recommended special electric fence wire that can handle 10,000 volts. It looks aluminum. The fence techs told me copper is only rated for 600 volts. And the power will leak through the insulation. They also say copper will corrode and created insulated spots. Does this mean that aluminum doesn\'t corrode and is it superior to copper? Is is all a lobbying scam to force us to buy copper? Can I use the electric fence wire in my solar wiring?The fence tech advise is wrong. Copper can withstand still higher voltage and there is no limitation at all. The limitation of sustainable voltage only depends on the thickness of insulation and its dielectric strength. perhaps, the fence tech told you that that particular wire israted for 600 V, it may be true. The use of copper and aluminium depends on your economy only and the atmosphere to which it is exposed. normally in both copper and aluminium hanged in atmosphere (fence application) both are inert to atmosphere, both creates a oxide layer which inhibits further corrossion. In some high power wiring the power loss in aluminium wire become perhaps significant comparred to the economy. So you will have to use copper. One advantaeg of coper is, it can be drawn to fine wire and so more releable if used as stranded wire. But aluminium is difficcult to draw into fine wires and if used as solid, more prone to break. (This is applicable to copper also.)Why in the name of G-d are solar panel installations using higher than 600 volts? I can\'t imagine the clearances in the panels will stand 10,000 volts without jumping arcs. It is true that the rubber insulation used on most wiring is rated at 600 volts breakdown - special neon rated wire is used for higher voltages, which can also be copper. When you say electric fence wire, you actually mean the short wires that run from the high voltage source to the end of the bare wires which are usually steel to withstand the force of animals who bump into them before the shock drives them off and which is the wire most of us think of as fence wire. There is a problem using aluminum wire, especially in houses, because it forms a hard oxide surface very quickly and expands and contracts more than copper, so it must be used with special connectors that break through the layer and grease that keeps off the air. If you are using 8 gauge wire, you are doing it because of fairly high amps, which usually involves low voltages and solar arrays I have looked into have been 12, 24 and 48 volts. If your system is putting out 30-40 amps at 600 volts, you are 18,000 watts or more through 1 set of wires. Really? Or am I mixing two systems?I believe the fence techs are mistaken. On an electric fence, the wire is basically bare, and the periodic 10 kV shocks are very low current. Aluminum is cheap, and once it develops surface oxidation, will last. Copper would last, too - it would just cost more. For photovoltaic panels, copper is almost always the wire of choice. At #8 or larger, use stranded, of course. Copper has less resistance, which will be important in low-voltage PV. Also, aluminum wire cannot be simply put into fittings designed for copper; it must use special fittings designed for aluminum, or connected to copper with a wire nut and antioxidant.yes copper wire is better than almunium since coppe is very best conductor that that of almuniumOther related question