PHOENIX CONTACT Non-incendive barriers use current and voltage limiting circuitry to minimize the risk of ignition in hazardous Class I, Division 2 or Zone 2 environments. Devices limit energy to safe levels, which prevents arcing or sparking and allows live wiring on the device in a Class I, Division 2 or Zone 2 area. Available in 2 versions, the PI/NI-2D/24 protects 24V digital signals in the event of a short circuit or over-voltage condition. PI/NI-2I/I limits the maximum short circuit current to 24 mA in 4-20 mA loops. It can be installed with two-wire 4-20 mA transmitters.