Recently, we smelt something and upon checking found that the incoming power supply cable has burnt. Upon pulling out the fuse, the burning was quite severe with the wood pad surface behind it burnt as well. I reported it to the power supply company who replaced the whole set. What caused the overheating and the burning?

Predominently due to arching - induced by loose connections in the high current carying circuits.

What might cause the looseness? The meter is pretty fixed to the wall. How often to check for looseness to prevent this? Look like the failure is only noticable when it smelled a lot.

Are you using any technologies to help prevent the failures?

Nope.

Apparantly the nose test.....
You get what you use.

You should get a hold of Snell Infrared and talk to them about getting a infrared program started. Using thermography is a wonderful tool to find hot spots in you company's electrical systems. I don't know big your operation is but sounds like this would be the way to go. Here is there web site:

www.snellinfrared.com

We also have a company called Snell Inspections that can come in once a year or every quarter depending what your company needs are. There web is:

www.snellinspections.com

You can talk to someone at either location and they will get you on your way. Hope everything works out

Hello Josh,
seems like you either had a faulty cable, acurrent draw overload or a loose connection. I would also second Jeremy's recommendation of initiating a Thermography program to monitor electrical and mechanical issues (part of your condition monitoring program) irrespective who the vendor is, However I would couple that with motor current analysis or simply with monitoring the amperage draw on startup if you have the capability to do so from your control pannel.
Hope this information is useful.