Planning an instrumentation system that includes non-incendive rated pressure transmitters located in a Class I, Div 2 Group B area. The transmitters are 24 VDC excitation power and 4-20 ma signal. The power supply and data acquisition components will be located in a non-hazardous area. The DAQ system is rated as non-incendive. The question is rating/type of the 24 VDC power supply. Can a standard instrumentation power supply be connected to the transmitters with standard instrumentation cabling under the assumption that the non-incendive pressure transmitter itself is the energy limiting device that makes it safe in the hazardous area? Or, is a current limiting, multi-channel power supply, similar to a multi-channel segment protector required to individually limit the current available to each connected transmitter? The transmitter comes with a control drawing.
Can you also list the NEC, or other codes that relate specifically to the power supply requirements? Thanks.
Can you also list the NEC, or other codes that relate specifically to the power supply requirements? Thanks.