Dave, (with all due respect NOT to fight or argue ONLY to correct to others for the record)
NOT NECESSARILY, HERES THE REAL DEAL.....Youre close but no cigar as they say
WHILE ITS INDEED TRUE "ANY" LEG IN A 208 Y 120 Volt Three Phase Four Wire Service has:
120 VAC Single Phase to Neutral
BUTTTTTTTTT if its a 120/240 Volt Three Phase Four Wire Center Tapped DELTA
THEN ONLY TWOOOOOO LEGS HAVE 120 TO NEUTRAL
THE OTHER THIRD RED/HIGH LEG IS 208 TO NEUTRAL
In my over 40 year Electrical Ebgineering career there were times I specified 208 Y 120 Volt Three Phase Four Wire Services and other times I specified 120/240 Volt Three Phase Four Wire DELTA (and often the one leg was center tapped so 120 was available on TWO but NOT 3 legs, the odd one is 208 to Neutral NOT 120!!!
A DELTA IS NOT A Y AND 208 DOES NOT EQUAL 240
120 times the square root of 3 equals 208 NOTTTTTTTTTTTTTTTTTT 240.
There are 240 volt three phase gensets (could be pure 240 DELTA with three legs of 240 single phase or 240 three phase) and if you center tap one leg you get 120 but the other (red/high) leg to Neutral is 120 x 1.732 = 208 NOT 240
Theres 208 Y 120 Volt three phase gensets with ALL THREE legs of 120 to Neutral or 208 (120 x 1.732) three phase
This may be confusiung to lay persons but its pretty common engineering practice HOPE THIS HELPS AND DONT CONFUSE YALL Im here to help if I can NOT stir things up lol
John T Longggggg retired Electrical Engineer