Power load

A preliminary sizing for total power load can be obtained by adding the total power requirements for all devices to be connected.

For a more precise analysis of power distribution system requirements, you can request an IBM® System Power Profile Program printout from your seller. The System Power Profile Program, controlled and operated by the service office installation planning representative, provides a vector analysis rather than an arithmetic summation of total power. The vector analysis takes into consideration power factor and phase relationships. In addition, it considers waveform distortions caused by the load and inrush requirements. Additional capacity should be planned for future expansion. Contact you service office installation planning representative for information on how to obtain a System Power Profile.

Primary power problem areas

Your system is designed to operate on the normal power supplied by most electrical utility companies. However, possible computer malfunctions can be caused by outside (radiated or conducted) transient electrical noise signals being superimposed on the power line to the computer. To guard against this interference, power distribution design should comply with the specifications discussed in this topic.

Failures caused by the power source are basically of three types:

Power line disturbances, such as, short duration dips in voltage as well as prolonged outages. If the frequency of such power failures is not acceptable for your operation, installing standby or buffered power might be necessary.
Transient electrical noise superimposed on power lines might be caused by a variety of industrial, medical, communication, or other equipment:
- Within the computing facilities
- Adjacent to the computing facilities
- In the vicinity of the power company's distribution lines
  Switching large electrical loads can cause problems, even though the source is on a different branch circuit. If you suspect such a condition, it might be advisable to provide a separate, dedicated feeder or transformer for your system directly from your power source.

If the transient-producing devices have been eliminated from the feeder and the computer room power panel and power line disturbances are still present, it might be necessary for you to install isolation equipment (for example, transformers, motor generators, or other power conditioning equipment).

Lightning protection

Installing lightning protection devices is recommended on the computer power source when:

The primary power is supplied by an overhead power service.
The utility company installs lightning protectors on the primary power source.
The area is subject to electrical storms or an equivalent type of power surge.

Lightning protection for communication wiring

Be sure to install lightning protection devices to protect communication wiring and equipment from surges and transients induced into the communication wiring. In any area subject to lightning, surge suppressors should be installed at each end of every outdoor cable installation, whether installed above the ground (aerial) or buried below the ground.

Information about lightning surge suppressors for communication wiring systems and recommended installation methods for outdoor communication cables can be found in the manuals for the specific type of data processing system that is being considered.