2 way wall socket question

[EFLImpudence]

Good point, I'd overlooked that. So much for the suggestion that is sometimes made on this forum that two single sockets is a better arrangement for two adjacent high-current appliances than a twin.

Why?

Two single sockets have twice as many terminals.

 

[stillp]

Quite.

 

[ban-all-sheds]

It says they are 13A sockets.

That's not an answer.

Please show me where in BS 1363 it says that in order to comply with the standard a twin socket has to be able to deliver 26A for any length of time and exhibit any particular behaviour or performance during or after doing so.

It doesn't matter for how long, or how often you say "but they are called 13A sockets" (nor how reasonable), the fact is that there is no requirement for a twin socket to demonstrate any performance in any area at 26A, and therefore there cannot possibly be any guarantee that one will perform in an acceptable way at 26A.

There just cannot be.

Maybe you think it is clever, or useful, to say that having to pass "a test at 20A for between 4 and 8 hours during which parts of the socket-outlet shall not exceed specified temperatures" is not the same as "it must pass 20A without overheating"

It is different. The test has a time factor included, your statement "it must pass 20A without overheating" does not. Can you not understand that something can be OK at a current of x amps for a short time, but can only withstand y amps for a longer time?

Maybe you think it is clever, or useful, to say that "it must pass 20A without overheating" is not a good way to describe a test which requires a socket to pass 20A for 4-8 hours and reach a stable temperature which is not too high, but I doubt you'll find many people who agree with you on that.

That is correct, but each of the sockets shall meet certain performance requirements at 13A.

Please show me where in BS 1363 it says that in order to comply with the standard a twin socket has to be able to deliver 26A for any length of time and exhibit any behaviour during or after doing so. If you cannot then the fact is that to comply with BS 1363 a twin socket does not have to pass any test, for any performance or behaviour, where it is loaded at 13A+13A.

 

[Risteard]

Each one, yes.

But not each one simultaneously.

Show me where the BS says that then.

The BS does not permit both outlets to carry 13A continuously. One is loaded to 14A (slight overload) and the other 6A. So a double socket-outlet is rated to carry 20A.

 

[ban-all-sheds]

That's not true.

It does not require a socket to be able to carry more. But it does not "not permit" one to be made which can.


PS - we should all await a clever and useful reply from stillp saying that "rated" is not the right term to use.

 

[Risteard]

That's not true.

It does not require a socket to be able to carry more. But it does not "not permit" one to be made which can.

Have you read the Standard?

 

[ban-all-sheds]

Yes.

 

[stillp]

Maybe you think it is clever, or useful, to say that "it must pass 20A without overheating" is not a good way to describe a test which requires a socket to pass 20A for 4-8 hours and reach a stable temperature which is not too high, but I doubt you'll find many people who agree with you on that.

Maybe they do not have test lab experience. It seems clear to me that a socket could pass 20A without overheating for some period of time less than that specified in the test, yet fail the temperature limits after 4 hours. Maybe you don't think it is clever, or useful, but I am only trying to clarify that the standard does not state that a twin 13A socket-outlet cannot carry, or is limited to, or need not be able to carry, a current greater than 20A.

Please show me where in BS 1363 it says that in order to comply with the standard a twin socket has to be able to deliver 26A for any length of time and exhibit any behaviour during or after doing so. If you cannot then the fact is that to comply with BS 1363 a twin socket does not have to pass any test, for any performance or behaviour, where it is loaded at 13A+13A.

There is not a statement in BS1363 to the effect that a twin socket-outlet shall be able to deliver 26A for any length of time. Such a statement would be unnecessary (except perhaps for the avoidance of ambiguity) since it has already stated that they are 13A socket-outlets.

PS - we should all await a clever and useful reply from stillp saying that "rated" is not the right term to use.

"Rated" can mean a lot of things, depending on the item concerned, and the qualifier. Many items have multiple ratings for different utilisation categories, conditions of use, etc. There, I hope you found that useful. Whether you found it 'clever', I don't much care.

 

[stillp]

That's not true.

It does not require a socket to be able to carry more. But it does not "not permit" one to be made which can.

Have you read the Standard?

I know BAS has, and I have a copy in front of me.

 

[ban-all-sheds]

It seems clear to me that a socket could pass 20A without overheating for some period of time less than that specified in the test, yet fail the temperature limits after 4 hours. Maybe you don't think it is clever, or useful, but I am only trying

Yes, you are, very.

You know that I have a copy of the standard, and you knew full well that when I said "it must pass 20A without overheating" I was referring to the test for overheating at 20A which a socket must pass.

Maybe you thought it was clever or useful to pretend that you had no idea to what I was referring when I said "it must pass 20A without overheating", but I doubt you will find many people who agree with you on that.

to clarify that the standard does not state that a twin 13A socket-outlet cannot carry, or is limited to, or need not be able to carry, a current greater than 20A.

Of course it doesn't, and I have never said that it does, and I have said that it does not.

But that is all it is required to do.

Spoiler: stillp spoiler

Awaits with interest, to see stillp pretend that he has no idea of the context of that, and will try to be clever and useful by pointing out that the standard requires a great many other things

It is not required to undergo any tests involving a prolonged load in excess of 20A, by the end of which it must have reached a stable temperature which must not be excessive.

Do you have any intention of explaining what kind of common sense makes you think that because a twin socket has to be OK at a total load of 20A it must therefore be OK at a total load of 30% more than that even though the standard imposes no requirements for performance at, and specifies no tests to be carried out at, that higher loading?

There is not a statement in BS1363 to the effect that a twin socket-outlet shall be able to deliver 26A for any length of time.

AFT.

Therefore, if no such requirement is mandated by the standard, what kind of logic leads you to insist that a socket must be able to perform satisfactorily under stress which exceeds that which the standard requires by 30%?

Such a statement would be unnecessary (except perhaps for the avoidance of ambiguity) since it has already stated that they are 13A socket-outlets.

It doesn't matter for how long, or how often you say "but they are called 13A sockets" (nor how reasonable), the fact will be that there is no requirement for a twin socket to demonstrate any performance in any area at 26A, and therefore there cannot possibly be any guarantee that one will perform in an acceptable way at 26A.

There just cannot be.

PS - we should all await a clever and useful reply from stillp saying that "rated" is not the right term to use.

"Rated" can mean a lot of things, depending on the item concerned, and the qualifier. Many items have multiple ratings for different utilisation categories, conditions of use, etc. There, I hope you found that useful. Whether you found it 'clever', I don't much care.[/QUOTE]
Like I said - given the context of this discussion about the 20A test, and the lack of any "26A test", we await (and are still awaiting) a clever and useful explanation of why, when Risteard said "So a double socket-outlet is rated to carry 20A", 'rated' was not the right word to use.

 

[stillp]

You know that I have a copy of the standard, and you knew full well that when I said "it must pass 20A without overheating" I was referring to the test for overheating at 20A which a socket must pass.

I know that you have a copy of the standard, and I knew what you were referring to, and I was aware that you had omitted to mention the duration of the test.

Of course it doesn't, and I have never said that it does, and I have said that it does not.

Jolly good. We can agree on that.

Do you have any intention of explaining what kind of common sense makes you think that because a twin socket has to be OK at a total load of 20A it must therefore be OK at a total load of 30% more than that even though the standard imposes no requirements for performance at, and specifies no tests to be carried out at, that higher loading?

Other than the fact that the standard considers that the requirement to not attain excessive temperatures in normal use is verified by the test? No, I don't.

there is no requirement for a twin socket to demonstrate any performance in any area at 26A, and therefore there cannot possibly be any guarantee that one will perform in an acceptable way at 26A.

There are requirements that apply to each socket-outlet, and there is no concession for those requirements to be reduced when two are mounted on a common faceplate.

we await (and are still awaiting) a clever and useful explanation of why, when Risteard said "So a double socket-outlet is rated to carry 20A", 'rated' was not the right word to use

Why should I say that it was the wrong word to use? I would say that the figure of 20A is wrong, for a product in full conformity to BS1363.

 

[ban-all-sheds]

I know that you have a copy of the standard, and I knew what you were referring to,

So you knew those things, and you knew the context of the discussion of what current a twin socket has to be able to carry, and yet you thought it would be clever and useful to say things like these:

To comply with BS 1363 a twin socket only has to stay below a certain temperature when supplying 14A+6A.

Not correct. It must not exceed certain temperatures during a specific test.

If a standard says "it must pass 20A without overheating", ...

The standard does not state "it must pass 20A without overheating", it states that socket-outlets shall not attain excessive temperatures in normal use, and adds a test at 20A for between 4 and 8 hours during which parts of the socket-outlet shall not exceed specified temperatures.

I doubt you will find anybody who agrees with you that they were either clever or useful.

Do you have any intention of explaining what kind of common sense makes you think that because a twin socket has to be OK at a total load of 20A it must therefore be OK at a total load of 30% more than that even though the standard imposes no requirements for performance at, and specifies no tests to be carried out at, that higher loading?

Other than the fact that the standard considers that the requirement to not attain excessive temperatures in normal use is verified by the test? No, I don't.

Are you aware that everybody must know the real reason why you have no intention of doing that?

Are you prepared to explain why you think that if the people who wrote the standard considered that "normal use" was 13A+13A they required the demonstration of not attaining excessive temperatures to be carried out at a lighter loading than normal use?

There are requirements that apply to each socket-outlet, and there is no concession for those requirements to be reduced when two are mounted on a common faceplate.

The only requirement relating to not overheating under load IS reduced to not overheating under a load less than 2x13A when two are mounted on a common faceplate!

I would say that the figure of 20A is wrong, for a product in full conformity to BS1363.

Can you show where, for a product to be in full conformity with it, BS 1363 requires it to be able to sustain a load of 26A?

I'll make you an offer.

I will stop trying to get you to understand that because the standard explicitly requires a twin socket to handle only 20A without overheating, and because it does not explicitly require one to handle 26A without overheating, your claim that because it is called a "twin 13A socket" it must be able to handle 26A is nonsense, shortly after you stop making that nonsense claim.

 

[stillp]

Can you show where, for a product to be in full conformity with it, BS 1363 requires it to be able to sustain a load of 26A?

Clearly I can't, since you are being too stubborn to understand. Can you show any concession for a 13A socket to be derated because it is part of a twin socket?

The only requirement relating to not overheating under load IS reduced to not overheating under a load less than 2x13A when two are mounted on a common faceplate!

NO! The requirement is that they shall not attain excessive temperatures in normal use. This is verified by a test. The test takes place at less than the maximum load that a twin socket-outlet shall be able to withstand.
Think about IP ratings; they are verified by tests that are, in some cases, as short as 10 minutes, yet the requirements of whichever IP rating is applied far exceed the duration of the test that is necessary for the verification that the requirements are met.

 

[ban-all-sheds]

Clearly I can't, since you are being too stubborn to understand.

It is not I who is being too stubborn to understand. And even if I were, my stubbornness would not prevent you from showing where BS 1363 requires a twin socket to be able to cope with a 26A load if it did require it.

It is not I who refuses (surely out of deliberate obtuseness) to join the dots between the following:

• "Normal use" is an undefined term.
• "Excessive temperatures" is an undefined term.
• No test of any performance or behaviour whatsoever is required of a twin socket delivering 26A for any amount of time for a twin socket to conform with BS 1363.
• The only test for temperature rise which a twin socket has to pass is to not overheat
  Spoiler: stillp clever and helpful pedantry

  And will you PLEASE stop trying to pretend that "not overheat" and "not attain excessive temperatures" aren't equivalent. It is neither clever nor useful for you to keep on doing that.
  and not to be still getting hotter after 4-8 hours under a load of 14A+6A.

Can you really not see? The ability of a socket to cope with any load would be of no use if it could only cope with it for a very short time, and that if sustained beyond that short time it overheated.

Can you really not see? A twin socket is required to cope with a 14A + 6A load for an extended period of time without overheating.

Can you really not see? If a twin socket does not have to pass any tests at 26A, the thing could burst into flames at that loading and still conform because to conform it does not have to undergo any demonstration whatsoever of its behaviour at that loading.


Let's call the 14+6A the lower bound.

And let's call 1,000,000 amps the upper bound.

We know that at the lower bound for several hours the socket has to not overheat, and to not still be heating up. Probably fair to say that at that lower bound it could cope indefinitely.

I think that without any testing we could all form a reasonable opinion that at the upper bound the socket would exhibit extreme thermal distress within a very short time.

So - somewhere between the lower bound and the upper bound a twin socket is not going to be able to "cope" with the current.

But at what point? We don't know, because to conform to BS 1363 a twin socket does not have to demonstrate any ability to cope with any load for any length of time apart from 14A+6A.

Would that point be 26A for 10 minutes? We don't know, because to conform to BS 1363 a twin socket does not have to demonstrate any ability to cope with any load for any length of time apart from 14A+6A.

Would that point be 26A for 4-8 hours? We don't know, because to conform to BS 1363 a twin socket does not have to demonstrate any ability to cope with any load for any length of time apart from 14A+6A for 4-8 hours.

Would that point be 26A for 1 hour? We don't know, because to conform to BS 1363 a twin socket does not have to demonstrate any ability to cope with any load for any length of time apart from 14A+6A for 4-8 hours.

Does the ability to cope with 14A+6A for 4-8 hours mean that it must be able to cope with any load beyond that? Clearly not.

Does the ability to cope with 14A+6A for 4-8 hours mean that it must be able to cope with 13A+13A? We don't know, because to conform to BS 1363 a twin socket does not have to demonstrate any ability to cope with any load for any length of time apart from 14A+6A for 4-8 hours.

Can you not see? WE DON'T KNOW.


When a conductor with resistance (such as those in a socket) carries current it will heat up. The more current it carries the more it will heat up. Eventually it becomes unable to dissipate the heat, and carries on getting hotter and hotter until either it, or things in its vicinity, start to overheat.

Spoiler: Egg-sucking grannies

Apologies to all those who realise this, but it truly does seem to be a concept which stillp does not grasp, given his insistence that something OK at xA must therefore be OK at 1.3xA

.

We know that at a sustained load of 14A+6A a conformant socket does not overheat.

We do not know that at any higher loading it does not overheat because to conform to BS 1363 a twin socket does not have to demonstrate any ability to cope with any higher load.

Can you not see? WE DON'T KNOW.

Can you show any concession for a 13A socket to be derated because it is part of a twin socket?

Concession from what? From the requirements for voltage drop? No. But voltage drop is not the issue - a 30% increase in a few mV would be irrelevant. A 30% variation in a 50° temperature rise would be another matter.

From the requirements for breaking ability? No. But it's hard to see how current flowing through one outlet in a twin socket could affect the breaking ability of the contacts or the switch in the other outlet. The heating effects on shared components of a sustained load would be another matter.

From the requirements not to overheat under a sustained load? Absolutely. A 1-gang socket has to demonstrate this with a load of 14A, and a total load on the supply cable of 20A. A 2-gang socket has to demonstrate this with a load of 20A, split 14A & 6A, that being the total load on the supply cable of 20A.

NO! The requirement is that they shall not attain excessive temperatures in normal use.

Of course.

For the benefit of those of us not as clever as you, please explain why "not overheating" is so far from being equivalent to "shall not attain excessive temperatures" as to merit "NO!".

And when you've done that, also for the benefit of those of us not as clever as you, please explain why they would specify a test for overheating at a load less than what they consider would the loading causing overheating in normal use.

This is verified by a test. The test takes place at less than the maximum load that a twin socket-outlet shall be able to withstand.

Oh right.

So if a tyre manufacturer is to claim that his tyre will not delaminate at 130mph he only has to show that it will not delaminate at 100mph. Makes sense.

So if a shelf manufacturer is to claim that his shelf will not collapse under a load of 26kg he only has to show that it will not collapse at 20kg. Makes sense.

So if an aircraft manufacturer is to claim that his aircraft's wings will not fall off under a loading of 2.6g he only has to show they will not fall off at 2.0g. Makes sense.


CAN YOU NOT SEE?

Think about IP ratings; they are verified by tests that are, in some cases, as short as 10 minutes, yet the requirements of whichever IP rating is applied far exceed the duration of the test that is necessary for the verification that the requirements are met.

I have thought about that.

And I can quite envisage that a 10-minute test is a perfectly good indicator of how the item would perform over a longer period, just as a 4-8 hour test of the heating effect of a 20A load on a socket is a perfectly good indicator of how it would perform over a longer period.

What I can't envisage is a manufacturer claiming that his product does not leak (or, in your argot, "experience unacceptable liquid ingress") at an immersion depth of 26m because he has shown that it does not leak at 20m.

 

[stillp]

We must apologise for the interruption of transmission, due to a few domestic problems. However the wife is now tucked up safely in a hospital bed*, so normal service can now be resumed.
Now, where was I?
Oh yes, Friday afternoon I spoke to an ex-colleague who deals with product compliance issues for a major manufacturer of wiring accessories. When I asked him how much current could safely be drawn from a twin socket-outlet his response was "For how long?". I suggested 30 minutes, when his next question was "Is it on a ring?". I suggested that we consider one with an incoming and an outgoing cable, as would be the case on a ring final, and unlike the heat rise test in BS1363 which only uses an incoming cable. He was confident that a good make of twin socket could comfortably carry 13A through each outlet under those circumstances. He told me that their in-house sample tests are performed at 15A on each outlet (exceeding the BS1363 test), then 14A + 6A, then 6A + 14A, and also 13A + 13A. Not all the tests are performed at all these combinations of current - I've forgotten the finer details due to Friday afternoon's events.
I now have some contact details for a couple of independent test labs, so I'll see what they have to say on the subject next week.

*Nothing too serious, and she should be out in a couple of days.