IBM 2220 Nways 300, Service Manual

Page: 25 / 264

Figure 0-7. LCB Grounding via Ground Wire
Ground Wire Connection on LCB
There are two ways to secure the ground wire on the LCB.
Figure 0-8. Standard Connection
Figure 0-9. Bellcore Specification Connection
This operation must be performed before any network connection.
Note: All the previous checking should indicate 0.1 ohm or less.
d. Building Grounding
Check there is less than 1 V ac between the metal housings of plugs, connectors,
receptacles, and so on, and any grounded point in the building. This can be any grounded
metal structure, such as the stanchions of a raised floor (if they are electrically connected
to building ground), a metal water pipe, building steel, and so on.
Notes:
1) When probing a painted metal part, be sure that the meter probe tip penetrates the paint.
2) Also check the plugs metal housing of incoming cables.
4. Circuit Breaker and Circuit Protector Rating
Each power box has one circuit breaker (CB) and six circuit protectors (CPs).
General and Product Safety
xxiii