Square D transformers that have 208Y/120 and 480Y277 secondaries which use wiring diagram #8 in publication 7400CT9601 available at
http://www.squared.com/, are all Tee connected.
I don't know how to include pictures so here is the text version (also from Square D's Dry Type Transformer Study Course) of the secondary winding arrangement.
On your graph paper draw a coil which is vertical and 2.08 inches tall, label the top as X1, the bottom as X3, and put a dot at the midpoint.
Now draw a second coil 1.80 inches long from the midpoint of X1-X3 and going horizontal to the left to terminal X2.
If you measure from X1-X3, X1-X2, and X2-X3 in all cases you will have 2.08 inches which corresponds to 208V.
Now if you place a dot (X0) in the exact center of the equilateral triangle formed by X1-X2-X3, you would find it falls on the horizontal winding you drew. A measurement would show it to be 2/3 of the way between X2 and the midpoint, or 1.2 inches which equals 120 volts.
The disadvantage is the windings need to use larger conductors, but this is not a big deal with small KVA sizes.
The advantage is less core steel.
