Electrical interlocks for heavy duty 30-1200A safety switches are available factory-installed or in kit form for field installation. Each kit contains instructions for proper field mounting. A pivot arm operates from switch mechanism, breaking the control circuit before the main switch blades break. Switches with electrical interlocks installed are UL Listed. For factory-installed electrical interlocks, add EI (for one contact) or EI2 (for two contacts) suffix to catalog number.