Seen the same Color Coding on a few newer Primary Risers - such as the one in this Image, in various parts of Southern California - and Northern California.

ØA = Yellow,
ØB = Red,
ØC = Blue.

ØA would be normally Black, my guess is the Yellow gives it a tagged color which helps eliminate any second guessing as to the Phase Arrangements (i.e. Black Tape on Black Insulation = ????).

Looks like the Phase arrangement on this pole ended up as A, N, C, B (if the 2nd from the left is a Grounded Conductor, that's the "N" - looks like the 4 wire Primary Feeders around here, however the Grounded Conductor normally lands on a White Insulator at each pole).
The offsetting of B and C would be from "swapping positions" at certain intervals, for tuning the lines per Capacitive Reactance.
See it done on all systems at certain intervals. Not sure what the proper term for it is (or the Linemans' slang term either), but I do know it's to keep Reactance in check.

Anyhow, IMO, that would explain why the "Backwards Rotation" of A-C-B is seen here.
I'm sure the other end (at the Transformer it's feeding via Underground duct) is "Phase Proper" - having the Yellow Tagged Feeder landing on H1, the Red Tagged Feeder landing on H2, and the Blue Tagged Feeder landing on H3.

My 2¢

Scott35

p.s. have seen our local DWP's Line Crews tag many Primary Feeders with wraps of white tape, numbered per Phase line as:

1 wrap = ØA,
2 wraps = ØB,
3 wraps = ØC

Will get some pic's of these for posting.

So far, the white tape has not caused any problems or fires, and the Electrons are not afraid to flow past these points when seeing the white tape.

[Linked Image]

Just a bit of humor!

S.E.T.

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!