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.

Procedure

  1. 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.
  2. Attention: Use lockout and tagout procedures as defined in the Electrical Safety for IBM® Customer Engineers.
  3. Verify the MAIN LINE circuit breaker (CB1) on the rear of each DC-UPS is set to Off (down). Refer to Figure 1.
    Figure 1. Rear view of DC-UPS DSU showing CB1
    Location codes for the DC-UPS (Models 961, 96E) (rear)
  4. Verify the DS8000® mainline power cables are not connected to the customer power.
  5. Verify that the mainline power cables are connected to the DC-UPS.
  6. Check the resistance of the mainline power cable connector ground pin (G) to the DC-UPS chassis. See Figure 3 or Figure 2 or Figure 4.
    1. Prepare the multimeter to measure 0.1 ohm or less resistance.
    2. Place one lead of the multimeter on the ground pin of the male plug on the mainline power cable.
    3. Place the other lead on the conductive metal of its DC-UPS chassis. Do this for each mainline power cable.

      Is there more than 0.1 ohm of resistance?

    Figure 2. Single-phase, 200 - 240 V, 60A, IEC60309 cable connector pins
    Single-phase, 200 - 240 V, 60A, IEC60309 cable connector pins
    Figure 3. Three-phase low voltage (200 - 240 V) 60A, IEC60309 cable connector pins
    Three-phase low voltage, 200 - 240 V 60A, IEC60309 cable connector pins
    Figure 4. Three-phase high voltage (380 - 415 V) 30A, IEC60309 cable connector pins
    Three-phase high voltage, 380 - 415 V, 30A, IEC60309 cable connector pins