Infrared Thermography for SMB Facilities: A Practical Guide

What thermography actually is

Infrared thermography is pointing a specialized camera at an electrical panel and reading the temperature of every component in the image. Loose connections, overloaded conductors, imbalanced phases, and failing breakers all show up as hot spots long before they fail catastrophically. It's the single highest-value inspection technique in electrical maintenance and it's required, implicitly, by Chapter 9 of NFPA 70B 2026 because you can't score Physical Condition honestly without it.

What you're looking for

Three patterns matter most:

1. Hot spots on connections — a single lug or terminal running 10–20°C hotter than its neighbors almost always means a loose connection. This is the classic finding and the easiest to fix.
2. Hot conductors — an entire cable running hot usually means it's overloaded. Sometimes it means the load has grown past what the circuit was sized for; sometimes it means a parallel conductor has failed and the remaining one is carrying more than its share.
3. Phase imbalance — if A, B, and C phase on the same three-phase feed are running at noticeably different temperatures, you have a load imbalance or a damaged conductor upstream.

The reference-based standard

Thermography findings are scored against the temperature of similar components under similar load, not against an absolute number. A breaker running at 45°C might be fine in one cabinet and alarming in another, depending on ambient temperature and loading. NETA's widely-used classification is:

• 1–3°C above reference — possible deficiency, warrants investigation
• 4–15°C above reference — probable deficiency, repair during next outage
• 16°C+ above reference — major deficiency, repair ASAP

"Reference" can be an adjacent identical component, an adjacent phase on the same circuit, or historical data for the same asset. What it can't be is "whatever feels normal."

Load is everything

A thermography scan is only meaningful if the equipment is actually running under load. Scanning a panelboard at 2am when the building is dark tells you nothing about whether a connection is loose — because a loose connection without current flowing through it won't heat up. NFPA 70B and NETA both require scans at a minimum of 40% of rated load, with higher load preferred. If your building's load varies, schedule the scan during peak hours.

How often

Chapter 9 ties frequency to the composite condition score, but a reasonable baseline for SMB facilities is:

• Annual — main service, switchboards, MCCs, and any equipment that scored below 3.5 on the last composite
• Every 2 years — distribution panels, motor loads, UPS systems
• Every 3 years — branch circuit panelboards in non-critical spaces
• After any event — lightning strike, fault, breaker trip, smell of burning, visible damage

Do it yourself, or hire it out?

Entry-level IR cameras now run around $500–$1,500 and are good enough for walk-through screening. A certified Level I thermographer with a higher-end camera will cost $600–$1,500 per day and produce a formal report with temperature readings, load conditions, and photographs for the record.

For insurance and audit purposes, a third-party Level I report is significantly more defensible than an in-house screenshot, especially for the critical gear (main service, switchgear, transformers). A reasonable SMB pattern is to hire out a formal scan annually for the top 10 most critical assets, and do in-house walk-throughs quarterly with a cheaper camera for everything else.

What goes in the records

Every thermography inspection should be filed with:

• Date, ambient temperature, and load conditions at time of scan
• Thermographer's name and certification level
• Camera make, model, and calibration date
• IR image and matched visible-light image of each asset scanned
• Temperature readings at reference and hot spots
• Classification (possible / probable / major deficiency)
• Recommended corrective action and target date
• Follow-up scan after repairs, proving the fix worked

The feedback loop into Chapter 9

After each thermography cycle, update the Physical Condition input of the composite score for every asset scanned. Clean scan → 5. Minor findings under watch → 3 or 4. Major deficiency → 1 or 2 until the repair is verified. This is how Chapter 9 is supposed to work: real inspection data drives real score changes which drive real inspection-frequency changes. It's a loop, not a one-time exercise.