A STEP BY STEP GUIDE
In this month’s blog article, we’re going to cover the basics of how to safely and properly conduct an electrical thermographic survey using thermal imaging equipment.
Firstly, please ensure you’re competent to do the survey asked of you; remember, electricity can kill and it’s vital that you’ve received proper training before undertaking any task such as this. Take time to make sure the environment is clean, well-lit and that other people know what you are doing. This is to protect both you and them from unnecessary danger whilst you complete the survey.
Following some basic principles can help you complete your thermal survey.
Next, be aware that electrical panels, distribution boards etc. all need to be energised and under load if possible. This gives you a much better chance of discovering any faults. If it’s not on, it’s not going to get hot! In an ideal world you would take the covers off all items to be scanned. This would allow you to see all terminations, however this isn’t always practical due to time constraints, the possibility of accidentally turning something off, or simply the customer’s preferences.
Reflections are something you need to be aware of. Hot items can appear in the image due to reflections on nearby shiny surfaces. Check that hot items in the vicinity are not the cause of heat on an inanimate object you’re looking at.
Check the ambient temperature and set it in the camera, then check the reflected temperature and set this the same as ambient temperature. Check humidity and set it to 50. Set emissivity to 0.96; if this is set incorrectly it will give drastic temperature differences!
When selecting an electrical colour pallet. use Iron for electrical surveys. White/red means hot, black/blue means cold.
The “iron” colour pallet is usually the best to use in this scenario.
Check the temperature range of camera and ensure that it’s within the expected range of the survey you’re performing. This would normally be -20 °C to 120 °C. Remember that sometimes cables, bus-bars, connections etc. can get hotter than 120 °C. If this happens, go back to the temperature range and change to 0-650 °C then change it back to normal range afterwards to give more accurate readings.
If you’re ever unsure about how best to safely perform an electrical survey, please stop and ask before carrying out any work. The most important thing is your safety, and the safety of those around you.
Watch this space for next month’s blog article, which will aim to answer some of the more common questions we get asked about conducting thermographic surveys and using the equipment.