Electrical interlocks for heavy duty 30 A through 1200 A 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.