HP rp7420, Service Manual, Page: 54 / 127

Figure 4-4 Safety Ground Reference Check
To measure the voltage, follow these steps:
1. Measure the voltage between B0 and A0. Take the AC voltage down to the lowest scale on
the volt meter.
2. Insert one probe into the ground pin for B0.
3. Insert the other probe into the ground pin for A0.
4. Verify that the measurement is between 0–5 V AC. If the measurement is 5 V or greater,
escalate the situation. Do not attempt to plug the power cords into the HP 9000 rp7420 server.
Checking the Voltage (Additional Procedure)
The voltage check ensures that all phases (and neutral, for international systems) are connected
correctly to the cabinet and that the AC input voltage is within limits.
This procedure must be performed if the previous voltage check procedure did not yield the
expected results as previously outlined.
NOTE:
If a UPS is used, see the applicable UPS documentation for information to connect the
server and to check the UPS output voltage. UPS user manual documentation is shipped with
the UPS. Documentation can also be found at
http://www.hp.com/racksolutions
.
1. Verify that site power is off.
2. Open the site circuit breakers.
3. Verify that the receptacle ground connector is connected to ground. For connector details,
see
Figure 4-5 .
4. Set the site power circuit breaker to On .
54 Cabling and Powering the Server