IBM Multiprise 3000 S/390, Installation Manual

Page: 18 / 175

2 Checking the ground/earth path
Perform the ground/earth path checks using either
Procedure A (below) or Procedure B (located on
the next page). Procedure A is the preferred
method in the USA if the proper equipment is
available.
The wall breaker should be OFF.
Procedure A (preferred in the USA)
This procedure checks for a ground/earth
impedance of one ohm or less at the receptacle
ground/earth pin using the ECOS C7106 tester
(make sure the ECOS tester is Model C7106).
1. Locate a “live” 120 volt outlet near the
receptacle that will be tested.
Attention :
Do not use a machine's convenience power
receptacle or a customer's receptacle with
GFCI protection.
2. Insert the ECOS C7106 tester into the 120
volt outlet.
3. Perform the impedance test as indicated in
the instructions on the face of the ECOS
C7106 tester.
4. Unplug the ECOS C7106 tester.
5. Plug the ECOS C7106 tester into the
ECOS #7565 Remote Ground Test Probe
(located in the ECOS tester kit).
6. Attach the alligator clip from this probe to
the ground/earth pin of the receptacle to be
tested.
7. Reinsert the ECOS C7106 tester into the
120 volt receptacle (you may need an
extension cord).
8. Repeat the test as specified in the ECOS
C7106 tester instructions, looking for an
indication of one ohm or less.
9. If the connector has a metal shell, unplug
the ECOS C7106 tester from the wall
receptacle (if the ECOS C7106 tester is not
removed, a spark may occur when the
alligator clip is reconnected) and reconnect
the alligator clip to the metal shell, then
reinsert the ECOS C7106 tester and repeat
the test. Refer to
Electrical Safety for IBM
Customer Engineers, S229-8124-04 for
more information.
1-4
Installing the System