Hi Ralph:
The "protective impedance" leakage current is
separately measured (8.1.4). The "protective
impedance" is connected between a live part and an
accessible conductive part, not to earth.
"Leakage current" and electric strength is
measured from each pole of the supply across basic
insulation (Table 4) to an accessible conductive
part, not necessarily through a "protective
impedance" (13.2).
The "protective impedance" is only subject to
transient overvoltages when the accessible
conductive part is touched, otherwise it is an
open circuit and there is no voltage drop across
it. I suppose this is the reason for not
subjecting the "protective impedance" to the
dielectric test. (If the part is touched at the
same time as a transient overvoltage, an electric
shock injury is not likely because transient
overvoltages are of very short duration.)
I can't provide a justification for not testing a
radio interference filter for both leakage current
and electric strength. The filter is a leakage
current path and is subject to transient
overvoltages.
Best regards,
Rich
From: McDiarmid, Ralph
[mailto:ralph.mcdiar...@schneider-electric.com]
Sent: Monday, June 01, 2015 12:30 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] leakage current tests
IEC 60335-1
13 Leakage current and electric strength at
operating temperature
Protective Impedance and radio interference
filters are to be disconnected before carrying out
the tests.
I suppose they are merely checking for an obvious
no-no, like using accessible chassis metalwork as
a current carrying conductor.
However, don't radio frequency interference
filters often have capacitors which use a metal
enclosure as a common connection point?
__________________________________________________
_____________________________
Ralph McDiarmid | Schneider Electric | Solar
Business | CANADA | Regulatory Compliance
Engineering
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