DS8000 Service Documentation Version 7.5

Checking rack power system ground continuity and voltage (plug in)

Before you begin

Attention: Use an IBM-approved analog multimeter. Do not use a digital meter.

Switch off the customer circuit breaker that supplies AC voltage to the mainline power cables.
CAUTION:
Do not connect the mainline power cables until instructed to do so.
Attention: Use lockout and tagout procedures as defined in the Electrical Safety for IBM® Customer Engineers.
Verify the MAIN LINE circuit breaker 1 (CB00) on the rear of each primary power supply is set to Off (down). Refer to Figure 1.
Figure 1. Rear view of PPS showing CB00
Verify the DS8000® mainline power cables are not connected to the customer power.
Connect the DS8000 mainline power cable to the PPS input power connector. Ensure both latches are secure.
Prepare the multimeter to measure 0.1 ohm or less resistance. Place one lead of the multimeter on the ground pin of the male plug on the DS8000 mainline power cable. Place the other lead on the conductive metal of its primary power supply enclosure. Refer to Figure 2 or Figure 3 for the location of the ground pin. Do this for each mainline power cable.
Is there more than 0.1 ohm of resistance?
- Yes, go to MAP2330 Repair rack ground continuity.
- No, go to Checking customer receptacle ground pin continuity with customer CB off (plug in).
Figure 2. Three-phase amp

Figure 3. Single phase, ground pin