I think you're misunderstanding -- grounding and bonding are similar, but separate. They are installed separately, and mandated under different parts of the electrical code. It's possible, has not always been required to join them. They are INTRINSICALLY connected, via equipment casings, at locations like pump motors that are required to be BOTH bonded AND grounded.

Here are some links you may want to check out:

http://www.poolforum.com/pf2/showthread.php?15099
http://www.poolforum.com/pf2/showthread.php?5210

http://forums.mikeholt.com/showthread.php?t=95495
http://forums.mikeholt.com/showthread.php?t=104422
http://www.erico.com/public/library/fep/LT1242.pdf