Checking customer voltage with customer CB on (wired)

Procedure

  1. Remove the lockout tag and/or device that was applied to each customer mainline AC voltage circuit breaker.
  2. Switch on the customer circuit breaker.
  3. Select the condition that applies:
    1. Customer power is three-phase high voltage (380 - 415 V). Go to the next step.
    2. Customer power is single-phase (200 - 240 V). Go to step 8.
  4. Prepare the multimeter to read line voltage ac.
    DANGER
    Dangerous voltages may be present. Do not touch the internal parts (pins and connectors) of the mainline power cable connector.
  5. For three-phase high voltage (380 - 415 V), at the mainline power cable connector (DC-UPS end), measure the customer three-phase voltage to ensure it is within the DC-UPS minimum and maximum input voltages.
    1. The nominal customer voltage of three-phase high voltage is 380 - 415 V (phase-to-phase).
    2. The measured voltage must be between the minimum and maximum voltages of 342 - 456 V.
    3. Measure the voltages between each pair of voltage pins ( A  to  B ,  B  to  C , and  C  to  A ) on the main line power cable outlet. See Figure 1.

    Are all three measured voltages between 342 - 456 V?

    • Yes, go to the next step.
    • No, inform the customer that the voltages are not correct. Do not continue until the voltages are correct.
    Figure 1. Three-phase high voltage (380 - 415 V) mainline power connector at DC-UPS end
    Three-phase wye mainline power connector
  6. At the mainline power cable connector (DC-UPS end), measure the voltage between each voltage pin and ground ( A  to (G),  B  to (G), and  C  to (G)). See Figure 1.

    Are the voltages within 10% of each other?

    • Yes, go to the next step.
    • No, inform the customer that the voltages are not correct. Do not continue until the voltages are correct.
  7. At the mainline power cable connector (DC-UPS end), measure the voltage between each voltage pin and the Neutral pin ( A  and Neutral,  B  and Neutral,  C  and Neutral). See Figure 1.

    Is the measured voltage 180 - 264 V?

    • Yes, go to step 10.
    • No, inform the customer that the neutral line measured incorrectly. Do not continue until the customer corrects the situation.
  8. Prepare the multimeter to read line voltage ac.
    DANGER
    Dangerous voltages may be present. Do not touch the internal parts (pins and connectors) of the mainline power cable connector.
  9. For single phase (200 - 240 V), measure the voltage between voltage pins  A  and  B . See Figure 2.
    1. The nominal customer voltage of single-phase is 200 - 240 V (phase-to-phase).
    2. The measured voltage must be between the minimum and maximum voltages of 180 - 264 V.

    Is the measured voltage between 180 - 264V?

    • Yes, continue with the next step.
    • No, inform the customer that the voltages are not correct. Do not continue until the voltages are correct.
    Figure 2. Single-phase mainline power connector at DC-UPS end
    Single-phase mainline power connector at DC-UPS end
  10. Continue with Connecting the mainline power cables (wired).