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Infrared Windows for Electrical Switchgear

Traditionally, proper conduct of an infrared inspection of energized electrical switchgear has required that panel covers be opened or removed prior to the infrared inspection. IR transmissive windows and viewports offer an alternative to this practice; however, several important issues must be considered prior to installing windows or viewports.

For many years, safety standards and laws have required that only qualified persons work on or near exposed energized electrical components. As safety standards have evolved, many facilities have sought ways to eliminate exposure of personnel during an IR inspection and the potentially lethal injuries associated with an arc flash.

Currently, a wide variety of commercially available inspection ports and IR transmissive windows are being offered as an alternative to removing panel covers for an infrared inspection. Prior to installing such devices one should bear the following in mind.

• Ascertain spectral response of chosen window to ensure that it is appropriate for use with your imager
• Determine field-of-view for the subject window
• Identify number of windows and positioning to ensure adequate coverage
• Evaluate whether installed viewports will compromise safety by allowing easier access to energized components
• Consult with switchgear manufacturer to ensure that window installation will not void warranty or ratings of switchgear enclosure

Because much of the marketing information for windows is misleading, caution is recommended when considering the installation of windows in switchgear enclosures.

This Tip of the Week was submitted by Vance Cowper, Infraspection Institute Certified Infrared Thermographer #6370. Vance is employed by MCI.