Square D heavy duty Safety switches play a crucial role in today?s commercial and industrial settings, isolate power in daily activities, provide an effective way to interrupt power in an emergency, provide lockout on sight disconnect This Safety switch accessory is a field-installed standard neutral kit for 600A rated double through safety switches (series A). Terminal data for this accesory is 6 wires 250kcmil to 500kcmil aluminium or copper plus 1 wire of AWG 6 to 250kcmil service ground copper.