1A fuse in a 13A plug - what will happen?

[Discharged]

I'm trying to explain to my kid (8) why were have fuses in plugs, and he found a 1A glass fuse lying 'round and he asked me if we could put that into a 13A plug. I said 'no' it would blow if you plugged into the mains.

Then I wondered if that really would happen... So thought I'd better ask here for clarification.

What does happen if you put a too-lower rated a fuse into a plug? To my mind, what happens depends on the appliance being supplied - what current it draws.

Any idea on this, please?

 

[oldtimer]

Well first of all it would depend on the load so if you put it in a kettle,iron,toaster,washing machine the fuse would blow but if you put it in a standard lamp it would work but when the lamp or bulb comes to the end of its life then it could blow the fuse

 

[Discharged]

Thanks for that. So these 1A glass fuses would typically be aimed at protecting the simple, low demands of a much smaller appliance, like a clock radio perhaps?

 

[oldtimer]

Yes but there is a catch you cannot use these glass fuses in a plug top you have to use the same type of fuse and these are rated as 1,2,3,5,10,13 amps but most common fuses used are 3 and 13 amps in a domestic property the 1,2,5,10 are more common in a worplace

So Kettle ,toaster,washing machine, would be 13 amps
Standard light, PC, printer,clock radio would be 3 amps

 

[Peter Stanley]

this is ohm law P = I x V
The appliance is 800watts divided by 230 = 3.5 Amps
put a 1 amp fuse in plug it will go bang

 

[telectrix]

simply put, a 1A fuse will withstand a wattage if 230watts indefinitely, but can take around 1.45x that for up to an hour before popping.

 

[UKMeterman]

There is also another difference, when there is a short circuit hundreds or thousands of amps can flow. This high current will make an arc, a proper 1A plug fuse might make a bang but contain the arc. A glass fuse will do something like this ERA Technology Ltd - Low Voltage Electrical Product Testing

 

[dingledong]

but you get glass fuses in alarm panels and other things to . so i dont think it will explode unless you shoe a high voltage through, and even then i'm not sure

 

[Mr.Ian]

1amp fuses are used in 2 pin shaver adaptors but even then they are ceramic and not glass, glass fuses are used mainly to protect low current circuits on pcbs as far as i've found. Glass fuse in a plug with a faulty circuit might shatter the glass whereas the ceramic fuses contain the arc. If you powered say a vacuum cleaner or toaster with a 1 amp fused plug I doubt it'd even go bang it'd just melt the fuse element straight away. Interesting test all the same !!!!!

 

[UKMeterman]

Hi,
It all depends on the prospective fault current and energy avaliable into a fault. A glass fuse can clear a fault of 35A and in practice a bit more, ok for the safety low voltage side of some power supplies. The test shown is a fuse subject to a current of about 6,000 amps and has a lot more energy avaliable!!

 

[Rampage]

I don't think a glass fuse is the correct diameter for a 1363 anyway is it?

 

[kippaxkid]

all interesting theories.......slightly undone by the fact that a glass 20mm fuse and a cartridge fuse are different sizes.
kitkat wrappers would be required.

 

[JamesBrownLive]

There is also another difference, when there is a short circuit hundreds or thousands of amps can flow. This high current will make an arc, a proper 1A plug fuse might make a bang but contain the arc. A glass fuse will do something like this ERA Technology Ltd - Low Voltage Electrical Product Testing

So how is that fuse blowing when there doesn't appear to be anything connected to the plug :book:

Cheers

 

[MarkieSparkie]

all interesting theories.......slightly undone by the fact that a glass 20mm fuse and a cartridge fuse are different sizes.
kitkat wrappers would be required.

Wrong! I have 1 inch, 1A, LV, glass cartridge and 1 inch, 1A, BS1362, HBC, Ceramic cartridge fuses in front of me as I type.

 

[ian.settle1]

I'm trying to explain to my kid (8) why were have fuses in plugs, and he found a 1A glass fuse lying 'round and he asked me if we could put that into a 13A plug. I said 'no' it would blow if you plugged into the mains.

Then I wondered if that really would happen... So thought I'd better ask here for clarification.

What does happen if you put a too-lower rated a fuse into a plug? To my mind, what happens depends on the appliance being supplied - what current it draws.

Any idea on this, please?

A glass fuse does not comply with BS1362 for a start so should not be fitted to a plug top.