The Cooper Bussman Photovoltaic SPD solution consists of a base and locking module that features a combined disconnection and short-circuiting (shunting) device with safe electrical isolation to prevent fire damage due to DC arcs. An integrated DC fuse allows safe module replacement without arc formation. In case of insulation faults in the generator circuit, a reliable and tested fault-resistant Y circuit prevents damage to the surge protective devices. The green and red visual indicator flags show the module protective status (green = good, red = replace). Apart from this visual indication, the remote signalling option features a three terminal floating changeover contact that can be used as a make or break contact depending on the particular monitoring system design employed.

Modular DIN-Rail design with colour-coding and rejection feature makes it easy to identify, install and maintain
Built-in overcurrent protection eliminates the need for any additional fuse installation and wiring
easyID™ Visual indication and optional remote contact signaling make status monitoring simple
Fast-acting Short-Circuit Interrupting (SCI) technology responds efficiently to overvoltage conditions

Voltage surges, often referred to as spikes or transients are typically caused by switching of fluorescent lights, fuses blowing or nearby lightning activity. The worst voltage spikes are usually caused by lightning strikes and can reach up to 6000V, with current surges of over 3000A. The maximum size of the let-through voltage and current inrush depends on the location within the building's wiring system. BS7671: 2011 Amendment 1 Sections 443 and 534 cover risk assessment and provides guidance on protection of electronic equipment for installation engineers to follow. The fullest information on lightning and surge protection comes from the BSEN 62305 series of standards.