Surgelogic™ Type SDSA is used mostly in service entrance panels to provide an efficient and economical means of surge suppression. The surge suppressors use two pole spaces in a QO™ or Homeline™ load center, or NQ panelboard. SPD are three phase and are rated for use in an indoor or outdoor enclosure. Ideal for residential and light commercial use, these SPDs provide a dependable first layer of surge protection. Meter Socket has no By-pass. It is designed to protect electrical service and major household appliances, excluding electronic devices. Designed for 4 wire 208Y/120VAC three phase systems. Securing up to 50kA surge current per phase. This surge protection device is UL Listed.