GE Dash Port 2, Service Manual

Page: 48 / 108

4-8 Dash Port 2 Docking Station Revision A
2000966-138
Maintenance: Electrical Safety Tests
Ground (Earth) Integrity
Listed below are two methods for checking the ground (earth) integrity,
“Ground Continuity Test” and “Impedance of Protective Earth
Connection.” These tests determine whether the device's exposed metal
and power inlet's earth (ground) connection has a power ground fault
condition.
Perform the test method below that is required by your Country/Local
governing safety organization.
Ground Continuity Test
Completion of this test is checked by the following steps:
1. Disconnect the device under test from the power outlet.
2. Connect the negative (-) lead of the DMM to the protective earth
terminal (ground pin in power inlet connector) or the protective earth
pin in the Mains plug (ground pin in power cord). Refer to the US
120Vac power cord figure above.
3. Set the DMM to the milliohm (m
Ω
) range.
4. Connect the positive (+) lead of the DMM to all exposed metal
surfaces on the device under test. If the metal surfaces are anodized
or painted, scrape off a small area in a inconspicuous place for the
probe to make contact with the metal.
5. Resistance must read:
‹ 0.1 ohm or less without power cord
‹ 0.2 ohms or less with power cord
Impedance of Protective Earth Connection
This test unlike a ground continuity test will also stress the ground
system by using special ground bond testers.
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.