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Do covers need to be removed from electrical distribution boards?

The short answer to this is yes.

The use of thermography as a predictive maintenance tool is to identify anomalies such as poor connections as early as possible to enable remedial activities to be scheduled with minimum business interruption.

A poor connection can be identified at temperatures only a few degrees above ambient therefore unless the infrared camera is able to see through the panel covers, (which they can't) it is simply impossible to identify this type of fault in the early stages.

There are times when it may not be possible to remove covers for example:

  • the cover is mechanically interlocked with the supply isolator
  • the Health and Safety risk associated with removing the panel cover is unacceptable
  • in the case of MCB boards, the risk of inadvertently switching off an MCB whilst removing the cover will cause unacceptable business interruption

In the cases above it is still worthwhile surveying equipment with the covers on, as if the connection is bad enough, it may be possible to detect a fault before too much damage has occurred. It is very much a case of something is better than nothing. It should be recognized that if an anomaly is detected with the covers on, it is likely to require urgent attention which can create significant pressure on those in charge of managing maintenance activities around business operations.

The thermal images below show an MCB board both the cover on and with it removed. As can be seen from the image on the left, there is little sign of anything wrong as MCBs under load will operate at temperatures up to 60°C. However with the cover removed (Right), the prognosis is quite different.

Covers-on-vs-covers-off

The image below shows the right hand image again, this time thermally focused. From this it is clear to see that the cause of the temperature rise is due to a poor connection between the supply side of the MCB and distribution board busbar assembly.

MCB-with-cover-removed

To find out more about the use of thermography on electrical equipment contact us today with your enquiry.

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