4.8 Special Racking Situations
When the cue ball or fifteenth object ball interferes with racking fourteen balls for a new rack, the following special rules apply. A ball is considered to interfere with the rack if it is within or overlaps the outline of the rack. The referee will state when asked whether a ball interferes with the rack.
(a) If the fifteenth ball was pocketed on the shot that scored the fourteenth ball, all fifteen balls are re-racked.
(b) If both balls interfere, all fifteen balls are re-racked and the cue ball is in hand behind the head string.
(c) If only the object ball interferes, it is placed on the head spot or the center spot if the cue ball blocks the head spot.
(d) If only the cue ball interferes, then it is placed as follows: if the object ball is in front of or on the head string, the cue ball is in hand behind the head string; if the object ball is behind the head string, the cue ball is spotted on the head spot, or on the center spot if the head spot is blocked.
In any case, there is no restriction on which object ball the shooter may play as the first shot of the new rack.
If the cue ball or object ball is barely outside the marked rack area and it is time to rack, the referee should mark the position of the ball to allow it to be accurately replaced if it is accidently moved by the referee when racking.
[WPA rules]