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Thermography and NFPA 70B 2002 Edition

For the past decade, the document, NFPA 70B Recommended Practice for Electrical Equipment Maintenance, has recommended annual infrared inspections of electrical systems. The 2002 edition of NFPA 70B contains several revisions of which thermographers should be aware.

The 1994 edition of NFPA 70B outlined many important issues surrounding infrared inspections including training, equipment, required conditions, inspection frequency, and reporting. The 1998 edition expanded on these issues and referenced temperature limit benchmarks. The 2002 edition text is nearly identical to the 1998 edition for the chapter, “Infrared Inspections”; however, there are some important changes:

• Specifications for Infrared Inspections have been moved from Chapter 18-17 to
  Chapter 20.17
• Chapter 20.17.52 is a new addition, requiring that circuit loading characteristics be included as part of report documentation

The 2002 edition also contains a completely revised Annex I recommending infrared scanning at least once per year for the following equipment:

• Outdoor Substations
• Switchgear Assemblies
• Stationary Batteries and Chargers
• Motor Control Equipment
• Low Voltage Busway
• UPS Systems

As with previous editions, NFPA continues to recommend semi-annual or quarterly infrared inspections for equipment “…where warranted by loss experience, installation of new electrical equipment, or changes in environmental, operational, or load conditions.”