Type 3 SPD Class III Surge Protection Devices have a low discharge capacity. They should be used as a supplement to Type 2 Surge Protection Devices and in the vicinity of critical or sensitive equipment such as servers or computer equipment, hi-fi or home cinema, CCTV, intruder or fire alarms, safety equipment, CNC-controlled machinery, telephone systems, sockets and lighting.
Type 3 SPD is characterized by a combination of voltage waves (1.2/50μs) & current waves (8/20μs).