Equipment Grounding When Using Non-Armored Cable?

[TwoBlocked]

The situation I am looking at is in the natural gas industry, Class I, Div 1, Group D. In NEC 202, Article 501.10(A) (1) it lists the permitted wiring methods. Types of both armored and non-armored cable is permitted. Let's say I am wiring from a controller to a pressure transmitter fitted to gas piping. If I use armored cable, the armor satisfies the equipment grounding requirement. If I use non-armored cable another means of equipment grounding is required. Since this is gas piping I may not use the piping as an equipment ground. If I use a conductor within the cable, it must be at least 14 ga (not likely in instrument cable.) If I use a conductor outside the cable it must be at least 6 ga and attached to a fitting with a grounding screw?

It seems for gas piping, you need to choose armored cable in order to provide an equipment ground. Or am I missing something?

 

[petersonra]

When would piping of any type ever be suitable to use as an egc? The code generally requires the egc be run in the same raceway or cable as the circuit conductors.

 

[TwoBlocked]

Maybe I was thinking of the grounding electrode. Water pipe ok, gas pipe not ok. Still, what do you do with non-armored cable where there is no ground wire? If you are under 50 volts and in an unclassified area, no problem. But if a classified area, no?

 

[TwoBlocked]

I think I found the article that confused me:

NEC 202 250.96 Bonding Other Enclosures. (A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non-current-carrying parts that are to serve as equipment grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded ...

It got me to thinking that many metal objects might be used as a EGC, but that is not the case.

So I am thinking that a non-armored cable, in a Class I, Div 1 area, that does not contain a 14 ga or larger EGC within it has to be run in a conduit, gutter, cable tray, etc, acting as the EGC, which then is bonded to the equipment the cable is servicing. Can someone confirm this for me?