Jargon Busted: Thermal Imaging

The electrical world can be confusing and we’ve all come across some terms that don’t make much sense. That’s why in each issue of Wired we unravel a piece of industry gobbledygook and tell you what it means – In plain old English.

One of the tricky things about electrical systems is that often you can’t see faults without taking things apart. Not only is this time consuming, but it can also cost businesses money in paying for the electrical engineer’s time and for downtime in production.

This is why a thermal imager or thermal camera is a useful item in an electrician’s tool box.

What is thermal imaging and what has it got to do with badgers?

In short, thermal imaging is a non-intrusive, no-contact method of detecting electrical faults that are hidden to the naked eye.

If you’ve ever watched a nature documentary filming nocturnal creatures such as badgers, they may well have used thermal imaging for night-vision.

What are the benefits of thermal imaging?

Thermal imaging can be used as a fault-finding measure in a failed system or machine, or as preventative maintenance, as it can indicate faults that you may be completely unaware of.

When you think of the amount of electrical circuits likely to be in your workplace, it wouldn’t be a huge surprise to find that some of them are damaged or have become worn over time. But because electrical systems are largely hidden from view, these faults may not be obvious until you have a major breakdown.

In the interim, you may be paying out a lot of unnecessary money in wasted energy while your machinery is not working at its optimum level - plus any faults could be potentially dangerous if left as they are.

What sort of problems can thermal imaging detect?

Thermal imaging can detect a range of problems such as loose connections and the poor working of a motor. Dirt in a system can also cause components to overheat, risking power failure or even an electrical fire. If machinery has been incorrectly installed – or the wrong machinery is being used – thermal imaging can detect any overheating that could lead to machine failure.

Does thermal imaging measure heat?

Sort of. As a general rule, the warmer an object gets, the more radiation it emits.

Thermal imaging detects this infrared radiation and, based on the amount of energy detected, works out the temperature. This is translated into an electronic picture, or thermograph, which will highlight a warm object against the cooler area around it.

The infrared energy that an object emits is known as its heat signature.

What do thermal images look like?

Thermal images can be grayscale, with cold objects depicted as black, warmer ones in tones of grey and hot ones as white, or the thermal camera can add colour, with reds, yellows and oranges showing the warmer objects and greens, blues, purples and black showing the cooler ones.

Are thermal cameras easy to use?

Yes, in that they are essentially point-and-shoot tools. However, the skill comes in the electrical engineer knowing how to analyse the images produced by the camera and take remedial action.

Where can thermal imaging be used?

Pretty much anywhere that has an electrical system – so anything from manufacturing plants to office buildings.