C1D2 for R&D LPG Engine Testing

[rbalex]

The way I read 501.140(A), it doesn't comply because the connections to the engine are not listed type connections, of course. On the test chamber side of the connection, I'm not sure what sort off connection to use. I'm having a hard time finding anything that would meet code. I'm also not sure how to meet 501.140(B)(2) as well. The engine has its own separate grounding connection that isn't part of the 24V power supply to it. It's unclear to my reading of it if that's acceptable per NEC. It's also unclear to me how to properly seal these connections or if it's even required. I don't want them potted because the different engines get their electrical harnesses swapped out regularly, so I can't really pot them through conduit and the cables can technically pass gas through the connection at the engine to the non classified space.

Not every Subsection [501.140(A)(1) through (A)(5)] must necessarily apply; however, I understand your quandary.
It would appear to me that yours is an application of 501.140(A)(5). In this case,“portable,” simply means it can be moved, but not necessarily that it will be moved, after final installation. From the Merriam-Webster 11th Collegiate Dictionary (the NFPA dictionary for Definitions not in the referenced standard):

adjective
por·ta·ble
| \ ˈpȯr-tə-bəl \

Definition​

• 1a: capable of being carried or moved about

It appears to me, the real problem such as it is, is Section 501.140(B)(4).

Since you convinced your AHJ that this is a Division 2 location, read the last sentence. Where explosionproof equipment is required, I would probably fashion “whips” from the explosion proof equipment to otherwise listed cord connectors and convince the AHJ that this is an application of 590.3(C).

Bonding is another critical issue of Section 501.140(B)(2). That would be an issue in it’s final installation as well assuming that the assembly will ultimately be installed in a classified location. See Section 501.30.

 

[petersonra]

They vary. From about 200-2000 hp depending on the model.

Among other things I design control systems for diesel engine test stands, but none that small.

 

[kwired]

Mainly because the LPG is piped in there, used, and stored in that room. Yes, there are many other items that have been addressed because of this that are well covered in fire and building codes. I'm much more comfortable with those than the NEC.

Is the gas ever released into the general atmosphere in that room though? As Bob mentioned it possibly is not a classified area at all depending on conditions. The fact you have storage inside possibly complicates this some, most the time storage ends up outside just to make things easier or to cost less, but piping that doesn't typically get opened to the atmosphere on any regular basis (like connections for filling and/or dispensing) typically doesn't create a classified location, neither does storage outside of maybe areas near relief vents in the storage tank, those possibly can be piped out of the area to make that classified area exist elsewhere though.