Configured with protection mode of Line-Ground and Neutral-Ground, pluggable 3-phase 4-pole Surge Protection Devices (SPDs) are UL Type 4 recognized and available with MCOV ratings of 150, 180, 275, 320, 420, 550, and 690 Vac. Thermal disconnect design accelerates thermal response time, protecting electrical equipment from incoming impulses, surges, and transient voltages. Each voltage module has unique voltage key to ensure appropriate voltage module and base are connected.