Why MCB and Fuse cant protect Voltage Surge?

[Shafiq Azmi]

Hi Everyone, I got some Power Module damaged cause by Voltage Surge. My device protected by 25A MCB and Fuse. Why my device still damage although its already have the protection? Any other way to prevent this from happening again?

 

[littlespark]

MCBs and fuses protect against overload of current, not voltage.

A surge protection device can be fitted which basically pulls any excess voltage into it and stops it from damaging devices.

They can be supplied as part of an extension lead or fitted at the consumer unit by a qualified electrician.…. But only protect equipment downstream from it.

They come as standard on a new board here in UK.