Confirming that this type electrical conduit is NOT approved for exterior use?
Thanks for your time fellow Inspectors
It’s probably just being used to protect the low voltage thermostat wires.
It is for thermostat. Doesn’t this type rust over time?
Looks like aluminum to me and it does not rust.
If it’s FMC then it’s not permitted in wet locations. Now if it’s a sleeve to protect a cable that doesn’t require protection in the first place then the answer is not so black and white. 
I suspect a sleeve for the tsat wires since there appears to be Carflex to the unit also.
If the wire inside it is rated for wet locations, it should be ok. If not then the MC should have a weather resistant jacket over it.(PVC coated mc)
II. Installation
330.10 Uses Permitted.
(A) General Uses. Type MC cable shall be permitted as follows:
(1) For services, feeders, and branch circuits.
(2) For power, lighting, control, and signal circuits.
(3) Indoors or outdoors.
(4) Exposed or concealed.
(5) To be direct buried where identified for such use.
(6) In cable tray where identified for such use.
(7) In any raceway.
(8) As aerial cable on a messenger.
(9) In hazardous (classified) locations
(10) In dry locations and embedded in plaster finish on brick or other masonry except in damp or wet locations.
(11) In wet locations where any of the following condi-
tions are met:
a. The metallic covering is impervious to moisture. b. A moisture-impervious jacket is provided under
the metal covering.
c. The insulated conductors under the metallic covering
are listed for use in wet locations, and a corrosion-
resistant jacket is provided over the metallic sheath.
where specifically
permitted by other articles in this Code.
I think that is better to have that than have the weed eater tear it up.
Like many I’ve seen.
Gray area… but according to this article, the rules of the conduit apply, and as another poster already said, FMC is not listed for wet locations. (Quoting the article: “The general consensus on this is that where Class 2 conductors are installed in a raceway the rules for that particular raceway apply.”)
That said, if the wire in it is rated for outdoors, it’s a non-issue, IMO.
@Jeffrey Belfus: If you don’t mind me correcting… this is FMC, not MC. Even though the two look the similar, MC is an assembled cable, where FMC is sold as an empty conduit that one can use for running one’s own wire(s).
The biggest issue would be if there were thermostat and high-voltage wires mixed and running inside. I would defer or at least point it out.
Based on the size it looks to small to be flex or Greenfield. I suspect it is MC sheath that has been slid over the t-stat wires.
Actually 3/8" FMC (greenfield) is about the size of the jacket on a 12-3 MC cable.