chassis isolation, contrary to UL1740?

[grambo]

I've been a mentor for about a year now, and I'm still confused as to why the chassis of the robot is not allowed to be electrically "bonded". I certainly don't know everything about safety or robotics, but I just got a docking station for a robot certified against the UL1740 spec (http://ulstandardsinfonet.ul.com/sco...p?fn=1740.html), in which the chassis is required to be bonded, essentially a single point connection to the power inlet's ground, capable of (in our case) handling 20A fault current from any piece of "exposed metal" if I recall the spec properly. This is in place in the UL1740 spec to aloow a loose wire to properly clear its fuse when it makes contact with the chassis. There's MILSPECs and NASA documentation for this sort of thing too... I have read a few posts about 2007 battery incidents, but I fail to see the logic of how those support isolation of the chassis.

Like I said, I certainly don't know everything, so if someone could explain this, or point me to an oficial FIRST post on this (am I the only one who has issues navigating their site?) I would certainly appreciate it.
Thanx in advance!