arpadveress 
Electrostatic charges capable of resulting in dangerous discharges must be prevented by means of appropriate measures.
Electrostatic discharge, as a source of ignition, is often within the control of the design of the installation, rather than the equipment, and backed up by standards providing appropriate detailed information.
However, the design of equipment can help to mitigate such risks and appropriate requirements are detailed in European harmonised standards.
Risk assessment related to hot surfaces and electrostatic charges, among other possible risks, shall be undertaken by the end user to ensure that any explosive atmosphere is not ignited.
Possible protection method here the application of earthing clamps, certainly clamps themselves shall be questionned as per possible igniton sources.
both cases addess simply the necessity of Ex protection, because “the clamps shall porvide evidence that it is actually making contact” – BUT:
Case 1: simple eathing clamp: Ex protection comes from the system, clamp is connected to system, where contect is displayed and enabled.
Case 2: complex earthing clamp: Ex protection comes from clamp based on above…: “the clamps shall porvide evidence that it is actually making contact”.
Keep up good work!
