standards and guidelines for communication sites - Radio And ...

POWER QUALITY CHAPTER 6: POWER SOURCES
6.3.7 GENERAL RECOMMENDATIONS TO HELP PROMOTE GOOD
POWER QUALITY
The following list presents some general recommendations to help promote good power quality. See
IEEE STD 1100-1999, Recommended Practice for Powering and Grounding Electronic Equipment.
• Use a UPS or other source of backup power on critical loads.
• Use a UPS system that provides a true sinusoidal wave output to help maintain a total harmonic
distortion (THD) below 5% (typically found in a UPS that uses IGBT rectifier technology).
• Isolate critical loads and electronic equipment from noisy or inductive loads (e.g. Motor driven
cleaning equipment, space heaters, fans, copiers and printers).
• Separate critical loads/ electronic equipment and other loads onto different panelboards (IEEE STD
1100-1999).
• Install an insulated grounding conductor on receptacles that feed critical loads or electronic
equipment, versus relying on the metallic conduit (IEEE STD 1100-1999, section 8.5.3).
• Match circuit availability to the load requirements (e.g., 15 amp circuits are not powering
equipment that requires a 20 amp circuit).
• Maintain minimum separation between AC power conductors and other communications cabling.
• Restrict access to power control panels and mark electrical receptacles according to use (e.g.,
HVAC controls, electrical panels and switch boards, circuits for critical loads or other uses).
• Follow the recommendations/requirements of Chapter 7, “Surge Protective Devices.”
• Follow the recommendations/requirements of Chapter 6, “Power Sources.”
• Follow the recommendations/requirements of Chapter 5, “Internal Grounding (Earthing).”
• Follow the recommendations/requirements of Chapter 4, “External Grounding (Earthing).”
• Follow the recommendations/requirements of Appendix B, Protecting Against Electrostatic
Discharge in Equipment Rooms and Dispatch Centers.
6.3.8 POWER QUALITY TESTING LOCATIONS
When monitoring a site that is serving several loads, it may be advantageous to initially install the
power quality monitor at the power panel feeding the system to obtain an overall profile of the voltage.
The power quality monitor can then be relocated to the circuits serving individual loads, or loads that
are experiencing malfunctions and failures. Comparison of disturbance data can help locate the source
of the disturbances and determine how to most effectively remedy the problem. (IEEE STD 1100-1999,
section 6.4.2.5.)
Motorola recommends the following locations for testing power quality:
• To assess the power quality delivered to an individual piece of electronic equipment, test at the
equipment's receptacle, especially if the equipment is exhibiting malfunctions and/or failures.
• To assess the quality of output power from a power conditioner or UPS system, test at the power
conditioner or UPS power panelboard (or as close as practical).
• To assess the power quality of secondary distribution, test on the secondary of the equipment room
transformer.
• To assess the overall power quality delivered to a facility, test at the facility's main electrical panel.
6-18 68P81089E50-B 9/1/05