NFPA 70B changed from a recommended practice to a standard with its 2023 edition. It covers maintenance of electrical equipment in commercial buildings, and infrared thermography is one of the preventive maintenance techniques NFPA teaches with it. A thermal scan finds hot connections before they fail. It does not replace the full maintenance program.
What is NFPA 70B?
NFPA 70B is the Standard for Electrical Equipment Maintenance, published by the National Fire Protection Association. NFPA describes it as covering preventive maintenance for electrical, electronic and communication systems and equipment in industrial plants, institutional and commercial buildings, and large multifamily residential complexes.
The first edition appeared in 1973 as a recommended practice. NFPA’s Standards Council issued the 2023 edition on December 27, 2022, and it became effective on January 16, 2023, when it was approved as an American National Standard. That edition moved 70B from the Recommended Practice for Electrical Equipment Maintenance to the Standard for Electrical Equipment Maintenance.
NFPA’s current listing shows a 2026 edition as the current edition, with issuance on November 19, 2025 and an effective date of December 9, 2025. Check which edition your insurer, lender or local authority refers to.
Why did the change from “practice” to “standard” matter?
A recommended practice says what should be done. A standard says what must be done. NFPA’s own commentary says the move gives the document “more enforceability.”
NFPA is also careful about the limits. Its author wrote that it may take time for jurisdictions to decide how to use and enforce 70B. NFPA does not name one agency that enforces it for every building. So the practical answer for an owner is to ask three parties how they treat it: the insurer, the local authority, and the party who wrote any maintenance requirement into a lease or loan.
On scope, NFPA staff quoted Section 1.3.1 of the 2023 edition: the standard “applies to maintenance for electrical, electronic, and communications systems and equipment” and covers systems typical of those installed for “industrial plants, institutional and commercial buildings, and large multifamily residential complexes.” NFPA said no commercial occupancy types are listed as exemptions.
Does NFPA 70B require infrared scans?
Infrared thermography is part of the standard’s maintenance toolkit. NFPA’s instructor-led training on 70B lists “proper maintenance intervals and preventive maintenance techniques, including infrared thermography” among its key topics, next to building an electrical maintenance program, switchgear, motors, transformers and overcurrent protective devices, and record keeping.
How often a task must be done depends on the equipment. NFPA’s committee draft for the 2026 edition includes a table of maintenance intervals organized by equipment condition (Condition 1, 2 or 3). In that table, intervals get shorter as the condition of the equipment gets worse.
Online summaries from vendors quote specific infrared intervals. We did not find those numbers in NFPA’s free materials, so we do not repeat them here. Read the table in the edition that applies to you, or ask the thermographer to cite the section.
What can an infrared scan find?
Calibre’s infrared page explains the principle. Every surface gives off infrared radiation in proportion to its temperature. A thermal camera turns that into an image that maps temperature differences. An overloaded electrical connection generates heat, so it shows up as a hot spot.
Two conditions apply to electrical scans:
- Load. Calibre notes that electrical inspections require circuits to be under normal load conditions.
- Interpretation. A trained thermographer reads the image in the context of the equipment and the conditions on the day.
Thermal imaging has limits too. Calibre’s page calls it effective but not infallible, and says findings are confirmed with other tools. NFPA lists infrared as one technique among several maintenance topics, so a scan is not a substitute for the rest of the maintenance work.
How do a 70B program and a pre-purchase scan differ?
| NFPA 70B maintenance program | Thermal scan during an inspection | |
|---|---|---|
| Who it serves | The owner or operator of the building | A buyer, lender or owner at one point in time |
| Timing | Recurring, on intervals set by the standard | One visit |
| Scope | Written program covering equipment, intervals and records | The equipment scoped for that visit |
| Output | Maintenance records over time | Thermal and visible-light photos with annotations |
A scan during a purchase gives a snapshot. It can warn a buyer about hot connections in the main switchgear or panels before closing. It does not prove the seller followed a maintenance program.
How does a scan fit a commercial inspection?
Calibre uses thermal imaging as part of the commercial building inspection process. Its page notes that full electrical panel assessments are scoped and priced as additions to the base inspection. Thermal findings are documented with thermographic images and matching visible-light photos, annotated with the nature and location of each anomaly.
Building-envelope scans for moisture and insulation have a different condition. Calibre notes they work best with a temperature difference of at least 15 to 18 degrees Fahrenheit between inside and outside. That figure is Calibre’s practice for envelope work. It is not an NFPA 70B rule.
If a scan raises a concern, the finding can flow into a cost-to-cure report so the buyer sees the cost with the rest of the property’s deficiencies. For background on large commercial electrical service, see our article on 480Y/277 volt systems. For a related fire-safety issue in older buildings, read about electric baseboard heaters. Thermal imaging also finds hidden moisture, as in our write-up of water intrusion under a commercial roof.
What should a good thermal report show?
Ask for these items:
- A thermal image paired with a visible-light photo of the same equipment.
- A label for the equipment and its location.
- A description of what the anomaly looks like and why it matters.
- The load condition at the time of the scan.
- A list of the equipment that was scanned, and what was not reached.
- A recommendation for the next step, such as repair, further testing by an electrician, or monitoring.
Next step
If you are buying a building with large electrical service, or you own one with older switchgear, tell us what equipment you want reviewed. Start with our infrared thermography service page, and see how it fits our commercial building inspection. Confirm with your insurer and local authority how they apply NFPA 70B to your building.
Sources
- NFPA 70B, Standard for Electrical Equipment Maintenance, standard development page
- NFPA, “Beyond the NEC: NFPA 70B is a Critical Tool for Reliability and Electrical Safety”
- NFPA, NFPA 70B instructor-led team training
- NFPA 70B first draft revision statements for the 2026 edition (maintenance interval table)
