I suspect this is not a Delta transformer because I often see some indicator or label identifying the B phase “wild leg”. However, Sometimes I see this inside the panel (orange wire as well) and sometimes outside. Not being able to take the panel cover off the 3 phase panel is certainly limiting. And the service entrance conductors were not color coded.
I am beginning to answer my own questions, (I think) Do all Delta’s have a “wild leg” ?(high leg, stinger etc)
I like to identify the type of service, specifically if it is a Delta. I’ll report on what I can verify. Also, if the wild leg is not properly identified at the correct locations, it may be noteworthy.
There is 3Ø, 3-wire and 3Ø, 4-wire Delta. The latter has the high leg. Easiest way to tell (besides testing with a meter) if there is a delta system without taking the cover off is look for single pole 120 volt circuit breaker on all three phases. If there are 120 volt single pole CB’s on all three phases then its most likely a Wye system.
If you count down from the top on each side the phase arrangement is A-B-C-A-B-C etc. You’ll see the the C phase has no single pole circuit breakers connected for 120 loads. That because the high leg voltage is 208 to neutral.
Happy to help. Just a quick thing about the 2-pole CB’s, if you look at the 3Ø, 4-wire Delta graphic in the OP you’ll see that any 2 poles will give you 208 volts so the fact that there is a high leg present in the system but that it doesn’t matter for 2 pole or 3 pole loads.