Let's get the Ranting over with first! Rant Mode = Enabled.
The installation looks horrible!
It resembles the same base material found inside of Fertilizer Bags, and therefore should be rated to it's "Bandini Value" - which, in this case, is a very high Bandini Value (+95.50% Bandini Factor)
EMT is as readilly available as MC Cable and Flex (Flexible Metallic Conduit).
It does require some "Talent", so there is a challenge for installation.
In the 4th Image, the "Appears to be recently installed" Panelboard could had been fed with a short EMT section between the two Panelboards, instead of running the Flex in to the bottom.
Running the Panelboard Feeders through the sides would have eliminated the "Stand-Off for a Stand-Off Strap" issue which resulted from having to "Weave" the Flex runs. (notice how the Mini is screwed to the wall via 4" long toggle bolt!)
Where the Pull Box is used, the amount of labor + materials involved to use MC Cable + Flex between the Panelboard and Pull Box, has got to be 1000% higher than any EMT installation could possibly run!
There appears to be at least (16) MC terminations, and at least (2) Flex terminations per run, so there will be (32) MC terminations and (4) Flex terminations total.
Think about how much labor is involved here!:
* removing the sheathing,
* inserting and landing the MC Connectors,
* making up the EGCs (Equipment Grounding Conductors),
* "attempting" to strap / secure the MC + Flex;
whereas (2) or (3) 1" EMT runs would only have (4) or (6) termination points, (1) properly sized EGC, correctly matched Neutrals per Circuit, and no strapping needed (appears to be less than 24" between the Panelboard and the Pull Box).
Lastly, the "Recently Installed???" Panelboard's front cover looks great where the Panel is mounted _IN_ a wall, but looks like Bovine Fecal Matter when used for Surface Mounting!
OK, Ranting is over.Rant Mode = Disabled.
There are a few Code Compliance issues to pick out, besides the obvious lack of interest with Article 110.12!
Outside of these items, the installations are Compliant.
1:] The "Avoid Contact of disimilar Metals" issue was attempted, but does not appear successful!
The Black Duct Tape "Appears" to me, intended for insulating the Aluminum Flex + Aluminum sheathing of the MC cable from the Steel Sprinkler lines.
The MC / Flex "bundles" may have a better chance at accomplishing this than the 1" Flex over the Sprinkler Head stub Tape job (First Image). The Tape should run past the Ells + Nipple to be effective.
2:] The MC Cables _SHOULD_ be supported _AND SECURED_ at maximum 6 Foot intervals, along with 12 Inches maximum at Termination points.
Not specifically defined per NEC, strapping methods could be anything that fits the definition of an acceptable means, however, the Cables would need to be _SECURED_ individually at the termination points (Panelboards and Pull Box).
3:] The Grouping of the MC cables may not Conform to NEC, per Article 330.
4:]The Flex runs _SHOULD_ be individually supported _AND SECURED_ at maximum 4-1/2 Foot intervals, along with 12 Inches maximum at termination points via an _APPROVED MEANS_.
5:] There is a possible listing issue with some of the Flex Connectors.
There are several which appear to be EMT Set Screw Connectors.
I am aware of Set Screw Flex Connectors, but a few of these look more like EMT Connectors.
6:] Article 300 mentions Cables shall not support other Cables. I see several places where this is done.
7:] K.O. seal needed in bottom of Pull Box.
8:] The use of a "Pipe Clamp" type Grounding Clamp is not listed (as far as I know) to connect (2) or more Conductors, as shown in the last Image.