Termination in Ex e Apparatus

Following good manufacturing and installation practices must be followed:

• Terminals must be designed to avoid sparking
• Clearance distance between terminals must be maintained
• Creepage distances over terminals and barriers must be maintained
• Two wires into the same terminal is not normally acceptable
• Heating effects in terminal can affect temperature classification

Examples are given below, of the Klippon terminal system, which is used in many enclosures.

The terminals are de-rated so that the maximum current for Increased Safety applications is nearly half that for standard industrial applications.

This de-rating, along with other considerations, ensures that internal and external surface temperatures are kept within limits.

When conductors are prepared for terminating they must have all wire strands retained within the terminal clamp. It is often practice to use crimped connectors/ferrule crimps on the end of each wire conductor to aid this termination requirement.

The parts description of common terminal rail components are given below in the next image.