Charles, et al,
>a) Does anyone one know the genesis of the requirement to lift the
Neutral AND the Ground simultaneously during a leakage current test??
(I am referring to UL6500)
answer a) A requirement to lift both the Neutral and the Ground
simultaneously during the leakage current test is a reasonable test to
apply to equipment which is not reliably grounded. This is a common
occurrence in the US, for intendance, because about half of the
electrical installations here do not yet have an installed 3rd wire
ground (since this was only required since the early 1960's). Folks
commonly use a 'cheater' (an adapter plug/socket combo without the
grounding pin on the male side) to install this equipment. Some other
countries have similar conditions. In this case, opening the neutral
would be the applied fault.
Where does this requirement appear in UL 6500? I don't find it
in clause 9.1.1?
>b) What human body model is appropriate for UL6500? Can I use the one
in UL1950??
answer b) The appropriate human body model for electric shock purposes
comes from the description in IEC 60479 (Effects of electric current on
the human body). This information has been used to develop the human
body model in IEC 60990 (Measurement of Touch Current and protective
conductor current). This 60990 circuit is used in several standards -
the 60950 family, the 61010 family, the 60065 family (hence UL 6500),
etc as well as UL 101/ANSI C101. This circuit is incorporated in some
common leakage current instruments, including the Simpson 228 (which I
use).
br, Pete
Peter E Perkins, PE
Principal Product Safety Consultant
Tigard, ORe 97281-3427
503/452-1201 fone/fax
[email protected]
