This is a 4 in PVC conduit that originates in a 1600A 480/277V 3 phase fused switchgear and feeds a single phase transformer. The transformer feeds a 240/120V 3 phase 800A breaker panel. The 4" PVC contains (3)350MCM conductors. The primary is fused @400A. This was installed in Nov. of '06. Check out the reducer to 3" where it turns into alum flex.
This install fits in the "close, but no cigar" category.
Using the flex, I see no need for the 45 before the 90. Hence, no need to take that chunk out of the structural steel.
(There's a time, place, and method to cutting structural steel ... but this is not it!)
I'd like to see some support for that flex as well.
A few other notes:
Even were the conduit steel, a ground wire is necessary. A neutral is not (on the feed side).
For the life of me, I cannot imagine a situation where you would NOT want a neutral to the secondary panel.
I do hope there's a main breaker in that panel.
I do hope the transformer is grounded, including on the secondary side. Grounded both with a wire back to the GEC, as well as to that structural steel.
Likewise, the neutral buss ought NOT be bonded to the case ... your 'bond' is at the transformer.
Now ... into "forbidden territory." While the NEC has information as to sizing conductors and breakers, I've never seen an inspector check them. This job has enough signs of a well-intentioned, but unqualified, job that those decisions ought to be reviewed.
I also agree; a three phase panel fed by a single phase transformer is a worry. I consider it a technical violation of code (look at the panel listing).
No, there is not a main breaker in the panel. What you see just to the right of the transformer is a 400A fused disconnect which is just ahead of the 800A MLO circuit breaker panel. It contains (4) 200A breakers that feed other panels throughout the building as well as 20A 2 pole breakers that feed MH lighting. This electrical work was done by an EC hired by the building owner. I was hired by the tenant to install conduit/conductors and connect their equipment. I will get more pics tomorrow to give everyone a better overview of this situation.
That stuff is legitimate. It's called flexible metallic conduit in the Code or Greenfield or "flex" in the real-world. It's very often used in short lenghts to make connections to equipment that vibrates, such as motors or transformers.
It's funny this should come up, because I was wondering about this practice the other day: Does anyone have any negative experience with non-flexible conduit being connected to transformers? The vibration is so slight that I have to question if FMC is even necessary. Especially since in many cases the pieces are of such a large diameter, and so short, that they aren't technically very flexible at all, and do very little to dampen the vibration of the tranny.
Using flex for that final bit is a trade practice. One of those habits we get into....
The last few transformers I have installed have had the cores suspended inside, not rigidly attached to the case. With that sort of construction, it is likely that things will be just fine without that bit of flex. At least from a vibration point of view.
I still like having some flex in there. If nothing else, it allows for the unforeseen complications ... like the transformer being replaced, or shifting when a forklift bumps it, etc.