I am trying to determine if a general purpose Instrument is acceptable for a Class I Div 2 hazardous area. A lot of vendors offer Intrinsically Safe or Explosion Proof variants, but this protection method is primaraly for Class I Div 1, and not necessary for Div 2. It seems to me that if the non-classified standard instrument meets 501.105, and is not included in 501.115-501.150, then it is acceptable in Class I Div 2.
I am looking at NFPA 70 2017 501.105 Meters, Instruments, Relays.
For 501.105(B)(1), does the "general purpose enclosure" refer to the overall enclosure that the device is mounted in: like a hoffman box? Or, does it refer to the actual device casing?
For 501.105(B)(3), do not all electronic Instruments contain some kind of resistor on their PCB's? Resistors are a basic building block of electronics, and I would expect to find at least one on any electronic instrument...
I am looking at NFPA 70 2017 501.105 Meters, Instruments, Relays.
For 501.105(B)(1), does the "general purpose enclosure" refer to the overall enclosure that the device is mounted in: like a hoffman box? Or, does it refer to the actual device casing?
For 501.105(B)(3), do not all electronic Instruments contain some kind of resistor on their PCB's? Resistors are a basic building block of electronics, and I would expect to find at least one on any electronic instrument...