• 1 or 2 channels in same package
  • Electronic protection prevents blown fuses
  • Higher-power barriers for group IIC and IIB gases
  • All models short-circuit proof
  • Fixed tagging & cable-screen earthing accessories
  • Certified to worldwide standards


The MTL700 series shunt-diode safety barriers are 1-channel or 2-channel devices that employ intrinsically safe techniques to allow electrical signals to be passed between non-hazardous (safe) and hazardous areas. They achieve this by limiting the transfer of energy in one direction to a level that cannot cause ignition of explosive atmospheres. Barriers that are connected in series with lines going to a hazardous area will protect wiring and equipment in that area from any faults occurring in the non-hazardous (safe) area, thus permitting a wide range of measurement and control operations to be undertaken safely.

Applications of MTL700 barriers include the protection of installations containing non-energy storing uncertified devices such as switches, thermocouples, resistive sensors, photocells and LEDs, or separately certified ‘energy storing' apparatus, for example ac sensors, transmitters and I/P converters. The barriers also enable maintenance work or calibration to be carried out without further precautions, and they permit non-hazardous (safe) area equipment to be worked on safely as and when necessary, with the minimum of restriction.

Essential features of the MTL700 Series are the self-checking ‘as-you-mount-it' earthing via two studs directly to nickelplated brass or copper busbar. The earth connection is on top of the unit, allowing easy inspection, installation and removal. The shape of the barrier has been designed for easy wiring, while the common (14.5 mm) space requirement of both 1- and 2-channel units simplifies planning or alteration of installations of all sizes. The busbar is insulated for separate earthing, to eliminate the danger of invasion by fault currents.