PIV electrics

[JohnW2]

But the argument is about whether that is their purpose, and if it is, why are they not needed in other countries?

That seems to be the argument that you, EFLI and some others are addressing, but that's not what I am talking about. I am talking about what a fuse actually achieves, or conceivably might achieve, regardless of what the 'intended purpose' of the fuse might have been.

My position is that (in the absence of a protective device within the load which will operate before any external device), no matter what the 'intended purpose' of an external fuse may be, it will also be the case the lower it's rating (provided it is high enough to allow the equipment to operate), the less energy will be dissipated within the load in the presence of a not-negligible-impedance fault, hence potentially less damage.

Opinions obviously vary, both within this forum and between experts in different countries, so it is not necessarily surprising that, although the Laws of Physics are the same in all countries, the experts in some countries have decided that the do not 'need' the additional degree of potential protection (no matter how small) that we are talking about. That is, of course, is unless you think that UK experts in this field are inferior to those in most other parts of the world.

Kind Regards, John

 

[ban-all-sheds]

I don't think they are inferior.

Nor do I think that they think that plug fuses are needed to protect appliances.

You could probably arrange to fit "close fire suppression" systems to each appliance you have, in order for there to be "potentially less damage" in the event of a fault.

But would that be a rational thing to do?

 

[JohnW2]

Nor do I think that they think that plug fuses are needed to protect appliances.

You have every right to have that opinion, but opinions about the meaning of "needed" in this context will obviously vary - amongst professional experts as well as the likes of you and myself.

We are probably agreed that if they did not exist in the UK (and related) places, just as they don't exist anywhere else, and particularly if our sockets circuits were limited to 16A, the view would very probably be that the potential (probably very small) advantage they might offer (with loads which were not optimally internally protected) did not justify the considerable upheaval (and cost) that would be associated with their introduction.

However, given that we do have plug fuses in the UK, it seems to me to a no-brainer that we should (with loads which are not, or maybe are not, optimally internally protected) use the lowest rated fuse that is adequate for the load.

Kind Regards, John

 

[JohnW2]

deleted - wrong thread!

 

[stillp]

Nor do I think that they think that plug fuses are needed to protect appliances.

Isn't the flex part of the appliance? Yet you (and others) insist that the sole purpose of the plug fuse is to protect the flex? Even if that were its sole purpose, do you not agree that it is sensible to provide that flex with the closest possible protection?

 

[stillp]

That seems to be the argument that you, EFLI and some others are addressing, but that's not what I am talking about.

Me too.

 

[stillp]

you do not have any evidence you can cite which shows that there are significantly more fires in electrical appliances in countries with similar electrical installation qualities to ours but without fused plugs.

No, I stated that there are significantly more fires 'of electrical origin' in other countries. Some will be initiated by the installation, some by the appliances, including their flexes.

But the argument is about whether that is their purpose, and if it is, why are they not needed in other countries?

That is not my argument.

My statement "To provide closer protection to the appliances that are connected to that installation.", with your emphasis, is not as you claim an "assertion that circuit OPDs are indeed meant to protect appliances.

there is nothing in a 23-page history of the 13A plug and the ring circuit written by a Fellow of the IEE which references any discussion of redundancy or failures

That is a correct statement. However my 'version' of the history is based on a verbal statement by another FIEE, who participated in the original work, whereas Mr Latimer, writing some years later, admits that "This paper is based on papers, particularly Committee, Sub-Committee and Panel minutes, found in the IEE archives; there are references to working papers which would throw light on some of the discussions recorded but there are none to be found in the archives."

 

[JohnD]

No, I stated

"claimed," surely?

 

[stillp]

"claimed," surely?

I made a statement.

 

[ban-all-sheds]

No, I stated that there are significantly more fires 'of electrical origin' in other countries. Some will be initiated by the installation, some by the appliances, including their flexes.

So in other words not one scrap of evidence that fused plugs provide any benefit in reducing fires originating in appliances.

That is not my argument.

Ah - so you are not arguing that the purpose of fuses in plugs is to provide any protection to the internals of appliances.

Good.

For it is not.

My statement "To provide closer protection to the appliances that are connected to that installation.", with your emphasis, is not as you claim an "assertion that circuit OPDs are indeed meant to protect appliances.

I really can't believe you wrote that.

I'll try again, with even more emphasis on what you wrote:

Following that, why was it considered necessary to fit other rated fuses in the plug - or did it just happen because there were such things - as John does?

To provide closer protection to the appliances that are connected to that installation.

Closer. Closer than what? Something cannot be closer than nothing. If the protection provided by the fuse in the plug is to be closer than the protection provided by something else, what something else could there be apart from the circuit OPD?

That is a correct statement. However my 'version' of the history is based on a verbal statement by another FIEE, who participated in the original work, whereas Mr Latimer, writing some years later, admits that "This paper is based on papers, particularly Committee, Sub-Committee and Panel minutes, found in the IEE archives; there are references to working papers which would throw light on some of the discussions recorded but there are none to be found in the archives."

That is hearsay.

In circumstances where veracity of evidence is considered important, hearsay evidence is not allowed.

So I guess it is up to you to decide how important it is here that what you say should be regarded as true.

 

[ban-all-sheds]

However, given that we do have plug fuses in the UK, it seems to me to a no-brainer that we should (with loads which are not, or maybe are not, optimally internally protected) use the lowest rated fuse that is adequate for the load.

It does not seem that way to me.

It does not seem that anybody has been able to produce any evidence that there are any benefits which accrue from that policy.

It is not a no-brainer to do something utterly pointless.

 

[JohnW2]

It does not seem that way to me. It does not seem that anybody has been able to produce any evidence that there are any benefits which accrue from that policy.

Given that we use plugs into which we have to insert a fuse, I think there really are only two possibilities to consider:

1... That it doesn't make any difference what fuse one uses, provided that it is large enough for the load, so one might as well always use the highest rated one which was adequate to protect the downstream cable (or 13A if the load was very unlikley to create an overload).
2... That it it is possible that, for smaller loads, there might, at least very occasionally, be a benefit resulting from using the lowest-rated fuse that allowed the load to function satisfactorily (both on switch on and during normal running).

I think we can discount the only other theoretical possibility, that using a fuse lower in rating than needed to protect the cable could in some way be 'harmful', so only the above two need to be considered. If the possibilities are either (1) that it "doesn't matter" or (2) that it is conceivable that a smaller fuse might sometimes offer some benefit, what would make one go with (1) rather than (2)?

Kind Regards, John

 

[securespark]

Perhaps he has a type of socket that does not take fused plugs.

Perhaps he has a 1363 socket attached to the "lighting" circuit?
[Shock horror]

 

[ban-all-sheds]

If the possibilities are either (1) that it "doesn't matter" or (2) that it is conceivable that a smaller fuse might sometimes offer some benefit, what would make one go with (1) rather than (2)?

Evidence and rationality.

It is conceivable that touching wood before turning on an appliance might sometimes offer some benefit, so I refer you to the earlier comment I made in another topic about superstition.

 

[JohnW2]

It is conceivable that touching wood before turning on an appliance might sometimes offer some benefit, so I refer you to the earlier comment I made in another topic about superstition.

You're talking there about doing something additional which is very probably unnecessary (and probably based on superstition).

I'm talking about a situation in which one has to put some fuse into a plug, and they all cost the same and take the same time/effort to put in. If one believes that "it doesn't matter" which one is used (with the provisos previously mentioned), one could, I suppose, toss a coin to decide which to use - but why not use the one which can be argued by some (even if you don't agree) to conceivable offer a benefit?

Kind Regards, John