Panel thermography uses an infrared camera to find hot joints, overloaded circuits and failing breakers before they fail. A loose terminal can run 40 degrees hotter than its neighbours without tripping anything. The camera sees it in seconds.
Quick Answer
A thermography survey is done with the panel under normal load.
Loose joints and overloaded circuits show up as hot spots.
A temperature rise above 10 degrees needs investigation.
Survey the main panels every 12 months and critical panels every 3 months.
Always confirm a hot spot with a torque check and a load reading.
What is panel thermography?
Panel thermography is the use of an infrared camera to measure surface temperatures inside an electrical panel and identify abnormal heat.
It means a non-contact survey that turns temperature into a maintenance priority list.
panel thermography in practice
How to grade a hot spot by temperature difference:
| Rise above reference | Severity | Action |
|---|---|---|
| 1 to 10 degrees | Normal | Record and monitor |
| 11 to 20 degrees | Watch | Recheck within 3 months |
| 21 to 40 degrees | Serious | Repair at the next shutdown |
| Above 40 degrees | Critical | Repair immediately |
| Hot breaker body | Internal fault | Replace the breaker |
| Hot cable across phases | Load imbalance | Rebalance the load |
What does a panel thermography survey cost in Nigeria?
A thermography survey of a main panel costs about 80,000 to 180,000 naira in Lagos.
A full building survey runs about 250,000 to 600,000 naira.
An annual contract for 4 surveys costs about 700,000 to 1,500,000 naira.
Repairing a loose joint costs 20,000 to 60,000 naira.
Replacing a failed breaker costs 40,000 to 250,000 naira.
A shutdown caused by a hot joint can cost millions in lost production.
How is panel thermography carried out?
- Review the panel schedule and confirm the normal load.
- Open the panel safely and establish an exclusion zone.
- Scan every breaker, terminal and busbar with the camera.
- Record the temperature and the reference temperature.
- Rank each hot spot by temperature rise.
- Repair critical spots and re-scan to confirm the fix.
Sources
IEC 62464 thermal imaging guidance, NFPA 70B electrical maintenance standard, Manufacturer infrared camera manuals, NIS 1000 electrical installation rules
How infrared finds a fault
Every electrical joint has some resistance. A loose or corroded joint has more, so it converts more energy into heat.
The camera measures infrared radiation and converts it to a temperature map. Hot areas stand out against the cooler panel.
The survey does not need contact or shutdown. That is why it is so useful for live panels.
What a survey can find
Loose terminal screws, worn breaker contacts, overloaded cables and unbalanced phases all show up as heat.
It can also find a failing busbar joint, a bad neutral and a loose earth connection.
It cannot see inside a sealed breaker. A hot breaker body is a sign to replace, not to open.
Survey conditions matter
The panel should be under at least 40 percent load. A lightly loaded panel may not show a fault clearly.
Avoid direct sunlight on the panel and wait for stable ambient conditions. Reflections confuse the camera.
Remove the dead front only if it is safe and authorised. Otherwise scan through the inspection window.
Reading temperature difference
Compare each joint with a similar joint on another phase, not with the room. The difference is what matters.
A rise of 10 degrees or less is usually normal. Above 40 degrees is an immediate repair.
Use the same emissivity setting for every reading. A wrong setting makes the numbers meaningless.
From report to repair
Photograph the hot spot, note the circuit and record the load at the time.
Rank the findings and schedule repairs. Critical spots should be fixed at once, not at the next annual shutdown.
After repair, re-scan the same joint under load. A confirmed drop proves the work was done.
Building a survey routine
Survey main panels every 12 months. Critical panels such as data centres and hospitals every 3 months.
Keep the reports in one file so you can compare the same joint year after year.
Train the maintenance team to look for discoloured terminals and smell hot plastic between surveys.
Related guides from this series
- Electrical Insulation Resistance Testing and Periodic Inspection in Nigeria
- Generator Thermography and Infrared Inspection in Nigeria
- Switchgear Maintenance Schedule
About the author
Illuminate Engineering Limited provides electrical maintenance and thermography surveys for commercial and industrial facilities in Nigeria.
Frequently Asked Questions
Do I need to shut down the panel for thermography?
No. The survey is done live under load. Only opening the dead front may require a permit.
What temperature rise is dangerous?
Above 40 degrees compared with a similar joint is critical. Above 10 degrees should be investigated.
How often should panels be surveyed?
Every 12 months for normal panels and every 3 months for critical facilities.
Can thermography find a bad breaker?
It can show a hot breaker body, which usually means the breaker should be replaced. It cannot see the internal contacts directly.
Conclusion
Thermography turns an invisible electrical fault into a photograph and a number. That makes maintenance planning much easier.
Survey under load, grade by temperature rise and repair the critical spots. Most panel fires are preventable this way.