Brian, et al,
A histerical, er - historical, review...
In an internationally harmonized standard all expected issues must
be considered. The primary driving factor for the cap discharge test on the
power input pins has been driven by the British over the years.
The large, 13A British power plug behaves differently than the North
American or Euro (or similar) plugs. When you pull a NA plug from the wall
and drop it in your hand the pins are parallel to your palm and spaced away
from you hand by the plug insulation (envision it in your mind as it is
described). Whether or not a voltage exists on the pin is not usually
important, the person holding the plug will not know if the voltage exists
there. The large, flat British plug seems to follow the 'perversity of
nature' rule and drop 'butter side down' with the pins in the palm of your
hand most of the time - thereby providing the shocking experience which is
deemed adequate to need mitigation. Hence the test to limit the sensation
to that which is acceptable.
I remember British colleagues on the committee pressing to have this
requirement properly included during standards harmonization discussion in
another standard.
History has never been a strong interest among most engineers so I'm
not surprised that small facts such as this fall away with time.
:>) br, Pete
Peter E Perkins, PE
Principal Product Safety Engineer
PO Box 23427
Tigard, ORe 97281-3427
503/452-1201 fone/fax
p.perk...@ieee.org
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