DS8000 Service Documentation Version 7.5

Checking customer ground continuity with customer CB off (wired)

Procedure

Prepare the multimeter to measure 1.0 V ac or less. Measure the voltage on the female ground pin on each mainline power cable and building ground. Refer to Figure 1 or Figure 2.
Is the voltage less than 1.0 V ac?
- Yes, go to step 3.
- No, continue at the following step.
Figure 1. Three-phase delta mainline power connector at DC-UPS end

Figure 2. Single phase mainline power connector
Voltage is present at a customer outlet with the customer circuit breakers off.
DANGER
Inform the customer that even though the circuit breaker is off, voltage higher than 1.0 V ac is measured at the failing customer voltage outlet pins.
Do not continue until the voltage is less than 1.0 V ac.
Prepare the multimeter to measure 1.0 ohm or less of resistance.
Measure the resistance between the female connector ground pin on each mainline power cable and the building ground.
Is the resistance 1.0 ohm or less?
- Yes, continue with Checking customer voltage with customer CB off (wired).
- No, inform the customer. Do not continue until the resistance is 1.0 ohm or less.