Electrical wiring and hardware: This includes the wiring, switches and circuit breakers required to connect the solar panel system to your home's electrical system. This guide breaks down pricing factors, material choices, and installation tips to help you budget effectively. Whether you're a contractor, installer, or DIY enthusiast, you'll find actionable. Most homeowners spend between $12,600 and $33,376 to install a complete residential solar system in 2026, with the national average at $19,873 before incentives. Your actual cost depends on your home's energy needs, roof characteristics, location and other factors, all of which we'll break down in. Average price of solar modules, expressed in US dollars per watt, adjusted for inflation. Using undersized wire in your solar installation can result in dangerous overheating, significant energy losses from voltage drop, and costly equipment failures. Stranded annealed copper conductors. 10 AWG Solar PV Photvoltaic XLP/USE-2 or RHH/RHW-2 Building Wire.