60A main fuse blew last night...

[justanotherguy]

EDF guy came 'round - replaced the fuse, but seemed VERY suspicious I'd done something. "What were you doing?", he insisted. "They don't just blow"

So, question is, what did happen? Was he right? Does it indicate sometging fundamentally broken?

Odd that the 'cartridge' fuse should blow, and yet nothing on the consumer unit flicked off. Also a separate 60A fuse before that didn't in a switch box didn't blow either...

 

[LoveRocket]

What were you doing? Lots of heavy loads on at once?
Shower?
Cooker?
Immersion?
Tumble drier?
Kettle?

60A is easily achievable.

 

[ColJack]

fuses do fatigue with age and spurious overload..
chances are you've run 60A through it from time to time ( electric shower? cooking at the same time maybe? heaters? etc.. )

 

[justanotherguy]

Biggest things I had on were washing machine and dryer (separate). Had some lights on, fridge/freezer. Didn't coincide with me turning anything on (unless the fridge went kicked in)

Obviously I'm not an electrician, so my simple question is - is the only way for the fuse to blow to draw more than 60A? I.e, couldn't be a faulty/old fuse that just 'wore out'

If I did draw more than 60A, where the heck did it go? The real killers like electric cooker/hob/kettle were not on.

 

[justanotherguy]

fuses do fatigue with age and spurious overload..
chances are you've run 60A through it from time to time ( electric shower? cooking at the same time maybe? heaters? etc.. )

Actually EDF guy mentioned showers - and nope, we have an unvented cylinder/gas boiler setup, so showers just run at mains pressure.

 

[ColJack]

not at the time of the fuse blowing, but previous overloads might have caused a reduction in the CSA of the fuse that would result in it's rating being lowered..

a house fuse can take double it's rating for a number of hours before blowing which is not to say that the increased temperature that it reaches doesn't have a detrimental effect on it.. ( see above ).

 

[LoveRocket]

What kind of CU do you have? Is it a modern MCB type? Any RCD protection? Tails in good nick? Any signs of overheating?

If you are concerned about this, get a spark in to do some quick tests to set your mind at ease.