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LEAKAGE TEST
The AC leakage from any exposed metal part to earth ground and from all
exposed metal parts to any exposed metal part having a return to chassis,
must not exceed 0.5 mA (500 microamperes). Leakage current can be
measured by any one of three methods.
A commercial leakage tester.
1.
Follow the manufacturers' instructions provided with the tester.
A battery-operated AC milliammeter.
2.
Measuring the voltage drop across a resistor by means of a VOM
3.
or battery-operated AC voltmeter. The "limit" indication is 0.75 V, so
analog meters must have an accurate low voltage scale. Nearly all
battery-operated digital multimeters that have a 2 VAC range are
suitable. (see Figure A)
To Exposed Metal
Parts on Set
0.15 µF
Figure A. Use an AC voltmeter to check AC leakage.
KDL-32R434A iii
AC
Voltmeter
(0.75V)
Earth Ground
CAUTIONS AND WARNINGS
HOW TO FIND A GOOD EARTH GROUND
The cover-plate retaining screw on most AC outlet boxes is at earth ground.
Verify the AC outlet box retaining screw ground by connecting a 60W to
100W incandescent (not a neon or fluorescent lamp) between the hot side
of the receptacle and the retaining screw. Try both slots, if necessary, to
locate the hot side on the line; the lamp should light at normal brilliance if
the screw is at ground potential. (see Figure B)
Trouble Light
AC Outlet Box
Figure B. Checking for earth ground.
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