Tech Tip

Zoned Approach to Power Quality


A Power Quality Solutions focus ensures continued performance and less maintenance on your microprocessor-based equipment.

Power Line Irregularities Happen!   Problems such as surges, noise, overvoltage, brown-outs, harmonics and blackouts can, at a minimum cause data disruptions and in some cases can even cause damage to sensitive equipment. Conducting a power quality check-up on your facility and providing a power quality solution for continued performance of microprocessor type equipment using the zoned approach is explained here.

Why a Zoned Approach?   A zoned power/data quality systems approach should be applied for multiple systems or problems.

Zones are Defined as:
Zone 0:     Outside (Uncontrolled) Environment
Zone 1:     Main Service
Zone 2:     Branch Panels
Zone 3+:   Point of Use

Before we begin with a general analysis, think for a minute about the solution you desire. At zone 1 where main service enters your facility you desire high energy handling. At zone 3, point of use or workstation, you’re looking for a tight waveform shape to nominal sine wave.

Follow These Steps

1.  Analyze your environment for its effect on electronic equipment.

• Is severe weather and lightning a common occurrence?
• Have you experienced nuisance failures, brownouts or other problems?

2.  Review the mechanical integrity of all systems.

• Check for loose wires or misfiring.
• Check for proper grounding, floating grounds or multiple grounds.
• Use thermal scanning equipment to locate troubled areas.

3.  Identify the problem.

• Field sample troubled areas with line-monitoring equipment, or define the disruption and potential causes to determine the problem.

4.  Evaluate what systems need to be protected in each zone.

Select power/data quality equipment to address the specific problems.

Zone 0: If experiencing lightning related spikes, strong RF signals, under-voltages, brownouts or blackouts, provide first level of transient control on all cables (power, voice, data) entering the building.

Zone 1: Surge voltage and currents from outside the building can appear on all conductive paths. Install hard-wired surge protection devices -- all incoming conductors, connect all system ground conductors to a common ground point, and connect all surge protection devices to the same common ground.

Zone 2: Residual spikes from service entrance and surges/noise originating within the building can be solved by providing supplemental layers of power/data quality protection in the form of surge protection devices or line conditioners.

Zone 3 thru end: Additional surges and noise surrounding point-of-use equipment can be solved by protecting distinct pieces of equipment via surge protection devices, line conditioners, isolation transformers, line/load reactors, stand-by power systems, or uninterruptible power supplies.


Article condensed from The Wiremold Company, Sentrex ED352-495.


Tech2 (orig.-7/31/02)