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Chapter 3
Installing the System
Setting Up the System
102
• Required method of grounding is to connect the green power cord safety ground to the site ground point.
This is accomplished through the power cord receptacle wiring. HP does not recommend cabinet
grounding. Cabinet grounding should be treated as auxiliary or additional grounding over and above the
ground wire included within the supplied power cord.
• As a minimum, the green power cord safety ground must be connected to the site ground point.
If the product ground is left floating, anyone coming into contact with the cabinet could receive a lethal shock
if a component should fail causing leakage or direct connection of phase energy to the cabinet.
If the product ground connects to a phase, the product will be over 200 volts above ground, presenting a lethal
shock hazard to anyone coming into contact with the product when site AC power is applied to the product.
Verify the connection of the product ground to site AC power ground through a continuity check between the
cabinet and site AC power supply ground. The continuity check should be performed while the site AC power
supply circuit breakers serving the cabinet and the cabinet circuit breaker are all set to
OFF.
Use the following procedure to verify that the product ground connects to the site AC power supply ground:
Step 1. Ensure that the site AC power supply circuit breakers serving the cabinet are set to
OFF.
Step 2. Ensure that the cabinet main circuit breaker is set to
OFF.
Step 3. Touch one test probe to the site AC power supply ground source.
Step 4. Touch the other test probe to an unpainted metal surface of the cabinet.
NOTE If the digital multimeter (DMM) leads will not reach from the junction box to the
cabinet, use a piece of wire connected to the ground terminal of the junction box.
Step 5. Check for continuity indication of less than 0.1 ohm.
• If continuity is not found, check to ensure that the DMM test leads are making good contact to
unpainted metal and try again.
• If continuity is still not found, disconnect the cabinet site AC power immediately and notify the
customer of the probability of incorrectly wired AC power to the cabinet.
• If continuity is good, and connection of the cabinet to site AC power supply ground (and not
floating or connected to a phase) is verified, then voltage checks may be performed.
NOTE For dual power source situations, proceed to the “Voltage Check” on page 108 with special
attention to PDCA 0 ground pin to PDCA 1 ground pin voltage. Anything greater than 3 V is
cause for further investigation.