Abstract: The present invention relates to the industrial field of wiring apparatus for cables and in particular to a connecting system for cables in intrinsic-safety industrial instrumentation boards. Directly on the assembling board where the intrinsic-safety modules for the protection of the process control systems are allocated, a plurality of connecting modules of the cross-wiring type are disposed to a card on which the intrinsic-safety modules relating to various protection devices are also disposed. In this manner all connecting cables coming from the various sensors distributed in an industrial plant can converge to this card in order to be sent to a central processing unit in a homogenous typology. The connecting modules are implemented on each card depending upon the plant extension and the amount of sensors present thereon.

Abstract: There is disclosed a barrier in which two or more Zener diodes are mounted in parallel in an encapsulated module between the leads from an input/output terminal located in a safe area to or input/output terminal in a hazardous area such as an environment having an explosive mixture of gases or dust, and a current-limiting resistor in series with an interconnected end of said diodes, wherein the circuit elements in the encapsulated module are connected individually at each end to one of a series of input/output pins extending from said module whereby they can be individually tested and the pins are adapted to be interconnected selectively externally of said module to complete the barrier circuit.