HP 3000 9x9KS - Dedicated Circuits; Frequency; Safety and Dedicated Grounds

2-8
Frequency
AC Line frequency is normally determined by your local power provider. In some cases, electrical
power is supplied by a customers motor-generators. Shifts in AC line frequency can cause system
errors or terminal display “jitter”. Your Hewlett-Packard CE can monitor the frequency of the input
AC line power and make recommendations, if required.
Dedicated Circuits
The HP 3000 and HP 9000 Enterprise Servers require dedicated circuits or individual branch circuits
(separate circuit breakers). This ensures that there are no other devices trip the circuit breaker and
ensures that there is sufficient power to run the system.
The ampere load of each circuit breaker should be designed to allow a margin for system start-up surge
current. Refer to Section 3 of the Computer Products Site Preparation Resource Guide and consult with
the Hewlett-Packard CE, to determine the circuit breaker requirements for your installation.
Safety and Dedicated Grounds
The primary reason for grounding electrical systems is safety. The safety ground is required by the
National Electrical Code (USA) and most other local, regional, and national codes. In addition to the
safety ground, Hewlett-Packard requires that a dedicated (earth reference) ground be installed as a
common reference point for all system components.
Basic principles of safe and effective grounding for any Hewlett-Packard computer system are
illustrated in Section 2 of the Computer Products Site Preparation Resource Guide. Consult with your
Hewlett-Packard CE and electrician to ensure that your system meets all national and local codes.