Takoma Park Volunteer Fire Department Postmaster )
said...

The real risk of bonding the exposed conductive frames of appliances to
the neutral is that if the neutral goes open the voltage on the frame of
the affected appliance/s will rise to the voltage to ground of the
supply source.

Yes, that is a definate and very serious reason for bonding equipment
with a separate, non-current-carrying, conductor.

However, the frequency of this occurring is relatively small (but not
insignificant). While the possibility of a neutral-bonded chassis sitting
at a volt or two above ground is somewhat higher (as in, it will be true
when the item is drawing a load, as well as when something else on the
same circuit is drawing a load). For the most part, this will not likely
pose a dangerous situation, but the potential is there -- it only takes
a few milliamps through the heart to be fatal.

--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
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