DC Surge Protection Device 1000V 2P 40kA (SPD)

Why Solar Systems Need Surge Protection

South Africa is one of the world’s most lightning-intensive countries. Gauteng, Mpumalanga, Limpopo, and KwaZulu-Natal experience over 80 thunderstorm days per year in many areas. A solar array on a rooftop — or even nearby infrastructure — can act as a lightning conductor, injecting transient overvoltages into the DC wiring that can destroy an inverter in milliseconds.

A DC surge protection device (SPD) is installed on the DC bus between the solar array and the inverter. When a transient overvoltage is detected, it activates in under 25 nanoseconds and diverts the energy to earth — protecting the inverter, battery bank, and charge controller.

Specifications

• Rated voltage: 1000V DC
• Configuration: 2-pole (one module per pole — positive and negative)
• Nominal discharge current (In): 20kA
• Maximum discharge current (Imax): 40kA
• Response time: under 25 nanoseconds
• Module type: Pluggable — replaceable without rewiring after a fault event
• Status indicator: Visual window (green = operational, red = module needs replacement)
• Mounting: DIN rail
• Operating temperature: -40C to +80C
• Standards: IEC 61643-31 / EN 50539-11

Installation

This SPD is installed in the DC enclosure between the solar array output and the inverter DC input, connected in parallel across the positive and negative bus. A separate AC-side SPD should be installed on the inverter AC output for complete system protection.

Installation should be by a qualified electrician. The SPD must be connected to a low-impedance earth bond for effective protection.

Return on Investment

A hybrid inverter replacement after a lightning strike costs R15,000 to R50,000 or more. Many South African household insurance policies now require certified surge protection for solar systems. At R549, this SPD is the most cost-effective protection available for your system investment.