Should I worry about lightning and micro-inverter protection?

Lightning Protection for Solar Micro-Inverters

Lightning strikes are a significant threat to solar panel systems, particularly those with micro-inverters. Direct strikes or nearby strikes can cause extensive damage, leading to costly repairs or even complete system failure. To mitigate this risk, consider installing a lightning arrestor, usually rated for surge currents of 10-50 kA, between the inverter’s AC output and the grid. This device will divert excess energy away from the inverter and the panel system.

Surge Protection Devices (SPDs) in Micro-Inverter Applications

Surge Protection Devices (SPDs) are another crucial component for safeguarding micro-inverters from lightning-induced voltage spikes. SPDs can be installed between the inverter’s AC output and the grid to absorb and redirect excessive energy. Look for SPDs that meet the IEC 61643-1 standard, which specifies surge currents of up to 20 kA for residential applications. When selecting SPDs, consider factors such as voltage rating, current rating, and compatibility with your micro-inverter system.

Micro-Inverter Grounding and Bonding

Proper grounding and bonding of micro-inverters are also essential for lightning protection. Ensure that the inverter’s metal casing is securely bonded to the grounding system, typically through a grounding rod connected to a grounding electrode. This will provide a safe path for lightning currents to flow harmlessly into the ground, protecting the inverter and the panel system. Use copper or aluminum grounding wires with a minimum diameter of 2 mm (1/8 inch) for optimal performance.