Triathlon rules vary by race and governing bodies. For individual
triathlons,
check the race packet for rules for the race.

For ITU races, the rules can be found at
http://www.triathlon.org/rules/index.htm

For USAT races, the rules can be found at
http://www.usatriathlon.org/Frames/fs_rules.htm

Even if your race is an ITU or USAT event, you should still check the race
packets for changes/exceptions to the rules.