• 10kA surge protection level
  • Transparent to fieldbus signals
  • <1mA leakage current @ working voltage
  • ±32Vdc operating voltage range
  • Minimum continuous operating voltage
    • ±32V peak normal mode
    • ±225V peak common mode
  • 62V limiting voltage @ 3kA 8/20μs
  • -40 to 167°F (-40 to 75°C) operating temperature


The MTL 9376-SP trunk surge protector is designed for use in the MTL 9370-FB range of fieldbus barrier systems. It prevents surges and transient overvoltages induced on the trunk of the fieldbus network from damaging the system's internal components, such as the fieldbus barrier module and terminator. Designed specifically for installation on the trunk terminal assembly inside the system enclosure, its pluggable construction allows it to be installed either during initial installation or later in the life of the apparatus.

The use of specially certified connectors allows the 9376-SP module to be removed and replaced in the fieldbus barrier enclosure in a Zone 1 hazardous area while the fieldbus trunk remains energized and without gas clearance procedures.

The 9376-SP's multi-stage hybrid surge protection network uses a combination of solid state electronics and a gas-filled discharge tube (GDT) to provide surge protection up to 10kA. It is completely transparent to the operation of the fieldbus, and allows the signals to pass without attenuation while diverting surge currents safely to ground and clamping output voltages to safe levels.

Fully automatic in operation, the 9376-SP reacts immediately to make sure that the protected equipment is never exposed to damaging surges between the fieldbus lines or between the lines and ground. It resets automatically without manual intervention.

When combined with a similar performance device at the host end (e.g. the MTL FP32 surge protector), there is effective protection for equipment at both ends of the fieldbus trunk.