Ten Amp Fuse in a Telly Plug (aka plugtop)

[Doggit]

I don't really understand what you are talking about - what sort of 'surge' did you have in mind, and how do you think that a fuse would offer protection against its effects?

I'm sort of picking brains in this discussion, and learning as I go, so bear with me. Now if the TV blows, the correct sized fuse in the plug will blow, but if the fuse is too large, would the Sky box for instance suffer any problems.

 

[JohnW2]

I'm sort of picking brains in this discussion, and learning as I go, so bear with me. Now if the TV blows, the correct sized fuse in the plug will blow, but if the fuse is too large, would the Sky box for instance suffer any problems.

The short answer is 'no'.

Furthermore, as I have said before, it is unlikely that a fuse in the TV's plug would achieve anything. A fault in the TV which resulted in a modest degree of 'excessive' current to flow would take out fuse(s) (which are hopefully present) within the TV before any fuse or breaker external to the TV operated. If something approaching a short-circuit arose in the TV, then the fuse or breaker in the CU would operate just as quickly as would any fuse in the plug. As I and others have said, 'fuses in plugs' are unique to the UK (and just a few other UK-related places), but the TVs are used 'everywhere'.

Kind Regards, John

 

[charliegolf]

All this is interesting, but I guess I was thinking, "Is this a fire risk to me and my family?", as opposed to the nitty gritty of damaging replaceables. But still interesting.

 

[winston1]

"Is this a fire risk to me and my family?".

No.

 

[big-all]

whilst i realize the fuse in the plugs only purpose is to protect the flex its connected to i always fit a fuse at or slightly below the rated value off the item it runs as most items will run well below the rated values most off the time
yes i am aware a fuse working close to or above rated values can cause heat issues so will check for heat build up for a few uses

as an aside before i fully understood ratings in the early 80s fitted my 650w microwave with a 3amp fuse and it lasted several years fitted a second 3amp fuse and when i finally threw it away noted it was something like 1000-1200w input

 

[ban-all-sheds]

.

 

[JohnW2]

whilst i realize the fuse in the plugs only purpose is to protect the flex its connected to i always fit a fuse at or slightly below the rated value off the item it runs as most items will run well below the rated values most off the time ...

To be frank, so do I, usually. Despite what BAS has just written, it's not because of superstition - more due to a realisation that an awful lot of things which should have their own internal fuses don't have them, and there is an outside chance that a low-rated fuse in the plug might minimise damage or problems if something went wrong within the equipment.

as an aside before i fully understood ratings in the early 80s fitted my 650w microwave with a 3amp fuse and it lasted several years fitted a second 3amp fuse and when i finally threw it away noted it was something like 1000-1200w input

That's not really surprising. Even 1200W is only about 5A, and that would take an awfully long time, if ever, to blow a 3A BS1362 fuse.

Kind Regards, John

 

[ban-all-sheds]

To be frank, so do I, usually. Despite what BAS has just written, it's not because of superstition - more due to a realisation that an awful lot of things which should have their own internal fuses don't have them, and there is an outside chance that a low-rated fuse in the plug might minimise damage or problems if something went wrong within the equipment.

Then how are these dangerous products legally on sale in places where there simply are no fused plugs, and why are people not scared to have them in their homes?

Will you please cite the evidence of damage or problems which happened when something went wrong within equipment which would not have happened had it been supplied by a fused plug.

 

[JohnW2]

Then how are these dangerous products legally on sale in places where there simply are no fused plugs, and why are people not scared to have them in their homes?

I didn't suggest either of those things. I merely said that there was an outside chance that an external low-value fuse might minimise the effects of a modest overload current. I'm not really talking about 'danger' (although I suppose there is a potential fire risk) but, rather, that 'outside chance' that it might minimise damage to the product.

Will you please cite the evidence of damage or problems which happened when something went wrong within equipment which would not have happened had it been supplied by a fused plug.

That is a question which cannot be answered. If a low-rating fuse in a plug blows, one doesn't know what would have happened in the absence of the fuse. If a piece of equipment which does not have a fused plug is extensively damaged as the result of a fault, one doesn't know what would have happened had there been a fused plug (with a low value fuse).

Given that there are really no downsides of which I am aware (a fused used within its rating shouldn't really 'overheat'), there seems no reason not to use a fuse with the smallest rating that is adequate.

Similarly, if I re-purposed a cable that had previously been used for a meaty shower to supply just an immersion heater, I probably would not leave the circuit with a 45A, or whatever, OPD, even those that would be OK to protect the cable.

Kind Regards, John

 

[Astra99]

Surely the bottom line is this. What is the CSA of the cable? If it is 0.75mm² then the fuse cannot be greater than 5A as the current carrying capacity of that flexible cable is only 6A. If it is 1.0mm² then a 10A fuse is permissible. However, there is a school of thought which says that the smallest fuse which will support the current requirements (including inrush currents) of the appliance would be fitted.

 

[JohnW2]

Surely the bottom line is this. What is the CSA of the cable? If it is 0.75mm² then the fuse cannot be greater than 5A as the current carrying capacity of that flexible cable is only 6A. If it is 1.0mm² then a 10A fuse is permissible.

All true, but I think the question in the OP rather assumed that the cable was suitable for protection by a 10A fuse, but felt that it was too high a fuse rating for the equipment in question...

However, there is a school of thought which says that the smallest fuse which will support the current requirements (including inrush currents) of the appliance would be fitted.

Indeed - and that is the school of thought I have presented in my last two or three posts in this thread. As I wrote in my most recent post, since I'm unaware of a downside, and can see a theoretical possibility that it 'just might' do good in some situations, I see no reason not to take that approach. After all, 3A (and even 1A - a good few of which I use) fuses are not particularly expensive

Kind Regards, John

 

[EFLImpudence]

Surely the bottom line is this. What is the CSA of the cable? If it is 0.75mm² then the fuse cannot be greater than 5A as the current carrying capacity of that flexible cable is only 6A.

Appliance flexes do not come under BS7671 so that simply is not the case.

Manufacturers will fit 0.75mm² and a 13A fuse for a kettle.

However, there is a school of thought which says that the smallest fuse which will support the current requirements (including inrush currents) of the appliance would be fitted.

There are schools of thought for all sorts of things.

and can see a theoretical possibility that it 'just might' do good in some situations,

Are there no examples for this theoretical possibility?

As you say, it will do no harm but the question is "Does it do any good?"

Is Europe burning?

 

[Astra99]

Appliance flexes do not come under BS7671 so that simply is not the case.

Manufacturers will fit 0.75mm² and a 13A fuse for a kettle.

Then that kettle will FAIL a Portable Appliance Test.

 

[EFLImpudence]

Why?

 

[flameport]

Then that kettle will FAIL a Portable Appliance Test

Unlikely, since most of those only involve some individual shoving a 'Pass' label on everything in sight and charging 14p.