SANS 60947-5-3-2005 低压开关和控制器.第5.3节:控制电路电器和开关元件.在故障条件下具有确定功能的接近开关的要求(PDF)
Low-voltage switchgear and controlgear Part 5-3: Control circuit devices and switching elements - Requirements for proximity devices with defined behaviour under fault conditions (PDF)