KnowledgeThe engineering behind continuous thermography:
what the code requires, how it deploys and how the methods compare
Written for electrical engineers, facility engineers and switchgear OEMs.
Grounded in the sources an AHJ and an insurer will accept, with every claim traceable to a source.
Grounded in the sources an AHJ and an insurer will accept, with every claim traceable to a source.
NFPA 70B (2026): permanently installed continuous monitoring permitted under §7.4.5
FM Global Data Sheet 5-19: online thermal monitoring recommended for critical switchgear
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What the Code Requires
NFPA 70B (2026) & FM Global Data Sheet 5-19,
and how SwitchMon® answers them
and how SwitchMon® answers them
NFPA 70B, a standard since 2023. Section 7.4 of the 2026 edition governs infrared thermography of switchgear and circuit breakers: temperature comparisons between similar components under similar load, and against ambient, documented and performed while the equipment is energized. §7.4.5 permits a continuously monitoring, permanently installed temperature measurement device to satisfy those comparisons.
FM Global Data Sheet 5-19 is the loss prevention standard of the party carrying the financial risk. It identifies permanently installed devices where conventional surveys are difficult and recommends online thermal monitoring for critical switchgear. Continuous monitoring supports an Electrical Maintenance Program; it does not replace one, and a monitoring product does not by itself make a facility compliant.
FM Global Data Sheet 5-19 is the loss prevention standard of the party carrying the financial risk. It identifies permanently installed devices where conventional surveys are difficult and recommends online thermal monitoring for critical switchgear. Continuous monitoring supports an Electrical Maintenance Program; it does not replace one, and a monitoring product does not by itself make a facility compliant.
Factory-Fit or Retrofit
Two deployment scenarios, one hazard
Factory-Fit: designed in during manufacture. Specified and integrated into new switchgear, switchboards, PDUs, UPS systems, transfer equipment and transformers during assembly, before energization. The thermal baseline is documented from first energization onward.
Retrofit: the patented IR Window Mount. Where a compatible IR window is already installed and appropriately positioned, the sensor mounts externally on energized equipment: no internal access, no downtime and no recertification for the sensor installation itself.
Retrofit: the patented IR Window Mount. Where a compatible IR window is already installed and appropriately positioned, the sensor mounts externally on energized equipment: no internal access, no downtime and no recertification for the sensor installation itself.
Periodic, Spot or Continuous
An annual survey, a fixed point sensor
and the whole thermal image, compared
and the whole thermal image, compared
A periodic survey sees the whole image, once. A scheduled thermographic survey captures the load, access and line of sight of the day of the visit; a condition that develops afterwards waits for the next survey.
A spot sensor sees one point, continuously. A fixed point sensor reports exactly one location, chosen at install time. A hot spot developing anywhere else on the bus bar, connection or breaker stays unseen until it reaches that point. Retrofitting internal spot sensors also means a full shutdown for safe internal access: a major switchgear OEM assessed more than 7 days of downtime to retrofit a five string switchgear line-up.
SwitchMon® gives you the whole thermal image. Continuously. Up to 19,200 temperature measurement points per image, up to four logical zones per sensor and ΔT virtual sensors, refreshed every 2 seconds. The IR Window Mount retrofits externally on energized equipment: zero downtime.
A spot sensor sees one point, continuously. A fixed point sensor reports exactly one location, chosen at install time. A hot spot developing anywhere else on the bus bar, connection or breaker stays unseen until it reaches that point. Retrofitting internal spot sensors also means a full shutdown for safe internal access: a major switchgear OEM assessed more than 7 days of downtime to retrofit a five string switchgear line-up.
SwitchMon® gives you the whole thermal image. Continuously. Up to 19,200 temperature measurement points per image, up to four logical zones per sensor and ΔT virtual sensors, refreshed every 2 seconds. The IR Window Mount retrofits externally on energized equipment: zero downtime.
Quick Guide & Checklist
The 2026 edition: continuous thermography monitoring
of switchgear and critical electrical equipment
of switchgear and critical electrical equipment
What changed since 2024, the three conditions of the P-F curve, what the code and the insurer ask, and two engineering checklists: one for new build (greenfield) switchgear, one for existing (brownfield) equipment in service. Every answer is traceable to a document, not an assumption. Aligned to NFPA 70B (2026) and FM Global Data Sheet 5-19.
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2026 edition · last reviewed 11 August 2026