GE Dash D 0 0005 G Series, Service Manual

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Revision B Dash Port Docking Station 3-9
2000966-037
Maintenance: Electrical Safety Tests
Impedance of Protective Earth Connection
This test unlike a ground continuity test will also stress the ground
system by using special ground bond testers i.e. Kikusui (model 872 or
TOS 6100) or Associated Research model HYAMP® Jr. Model 3030D.
This test normally is only required as a manufacturing production test to
receive safety agency compliance (i.e. IEC601-1).
Some country agency's do require this test after field equipment repairs
(i.e. Germany's DIN VDE 0751 standards).
Consult your country/local safety agency if in question.
Compliance is checked by the following steps:
1. A current not less than 10A and not exceeding 25A from a current
source with a frequency of 50 or 60 Hz with a no-load voltage not
exceeding 6 V is passed for at least 5 s through the protective earth
terminal or the protective earth pin in the mains plug and each
accessible metal part which could become live in case of failure in
basic insulation.
2. The voltage drop between the parts described is measured and the
impedance determined from the current and voltage drop. It shall not
exceed the values indicated.
For equipment without a power supply cord the impedance between the
protective earth terminal and any accessible metal part which is
protectively earthed shall not exceed 0.1 ohms.
For equipment with a power supply cord the impedance between the
protective earth pin in the mains plug and any accessible metal part
which is protectively earthed shall not exceed 0.2 ohms.
When taking this measurement move the unit's power cord around, no
fluctuations in resistance should be observed.