Installing extra appliance, electric supply advice needed

The fact that two socket-outlets are adjacent does not alter the fact that each has a current rating of 13A. There is no need for the standard to state the obvious.
So in saying that are you basically just completely ignoring the fact that BS 1363 does not require any testing to prove the accessories ability to support 2 x 13A loads, and that as far as you are concerned it is "obvious" that it must be able to?
 
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Simple Q:

Are you or are you not prepared to accept that a DSO does not have to be shown to be capable of supplying 2 x 13A in order to be deemed compliant with BS 1363?
 
The fact that two socket-outlets are adjacent does not alter the fact that each has a current rating of 13A. There is no need for the standard to state the obvious.
So in saying that are you basically just completely ignoring the fact that BS 1363 does not require any testing to prove the accessories ability to support 2 x 13A loads, and that as far as you are concerned it is "obvious" that it must be able to?
The standard doesn't specify all sorts of things, (UV resistance, resistance to cleaning chemicals, etc...) yet good manufacturers seem to be able to produce satisfactory products.
Do you believe that a good make of dual socket-outlet cannot withstand a total load of 26A for some unspecified period of time without ill-effects?
 
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As I've said in other threads, I believe the history is that, at the time BS 1363 was drafted, the plastics available were not able to cope with the heat produced by a prolonged test at 26A total, let alone the 28A that extrapolation from the other test would imply.
Fair enough, but are you suggesting that currently-used plastics are able to cope with the heat produced by long-term 26A (or 28A) - i.e. that the Standard could, if people so wished, now be modified to allow a greater temperature rise?
However, given that the manufacturers have no great incentive to give themselves more onerous tests to perform, the standard has not been updated in that respect.
Although I realise that many members of industry are involved, one might have hoped that the BSI would act in relation to what they regarded as the public interest, not the desire of industry to avoid 'more onerous tests' - I suppose I don't live in the real world!
Also, we apply diversity to all sorts of things, so why shouldn't BS 1363?
Not the least because of some aspects of my background, I am a strong supporter of the concept of diversity, where it is appropriate. However, as I say whenever this topic arises, although I have never experienced or witnesses such problems myself, I cannot ignore the reports I hear from electricians that running two 'heavy' loads (e.g. a WM+dryer) off one double socket not uncommonly leads to plug and/or socket damage.
The fact that two socket-outlets are adjacent does not alter the fact that each has a current rating of 13A. There is no need for the standard to state the obvious.
Like BAS, I am confused by this statement. There seems nothing obvious to me about the fact that two 13A outlets on the same plate (and with a common moulding) can both 'cope' with 13A simultaneously just because one is required to cope with 14A when the adjacent one is carrying 6A. Maybe I'm missing something.

Kind Regards, John
 
Do you believe that a good make of dual socket-outlet cannot withstand a total load of 26A for some unspecified period of time without ill-effects?
As I've just written, that is the crunch. I don't know what to believe, but I hear electricians telling me that they see 'ill-effects' due to 'two heavy loads' on a double-socket, even though at least one of them (usually a WM) is probably not drawing high current for more than fairly modest periods of time. Maybe they are imagining these 'ill effects' which they claim to see?

Kind Regards, John.
 
Although I realise that many members of industry are involved, one might have hoped that the BSI would act in relation to what they regarded as the public interest, not the desire of industry to avoid 'more onerous tests' - I suppose I don't live in the real world!
No, you don't!
BSI, like IET, does not write standards, any more than Penguin write books.
 
The fact that two socket-outlets are adjacent does not alter the fact that each has a current rating of 13A. There is no need for the standard to state the obvious.
Like BAS, I am confused by this statement. There seems nothing obvious to me about the fact that two 13A outlets on the same plate (and with a common moulding) can both 'cope' with 13A simultaneously just because one is required to cope with 14A when the adjacent one is carrying 6A. Maybe I'm missing something.
I'm sorry to hear that you and BAS find it hard to understand.If they were not intended to carry 13A, why would they be marked 13A? Does a 32A MCB have a different rating when installed next to another? or, indeed, when it is fitted with a double or triple toggle as part of a two-pole or three-pole MCB?
 
Although I realise that many members of industry are involved, one might have hoped that the BSI would act in relation to what they regarded as the public interest, not the desire of industry to avoid 'more onerous tests' - I suppose I don't live in the real world!
No, you don't! ... BSI, like IET, does not write standards, any more than Penguin write books.
It's sad. Whilst the BSI and IET don't literally write Standards, it would be nice if they exercised oversight to ensure that the public interest got precedence over commercial interests.

My father, who was a Standards Engineer in the aeronautical industry (and sat on various BSI committees), would be turning in his grave at the mere suggestion that the 'avoidance of more onerous tests' by manufacturers should be allowed to even be a consideration if the safety of aircraft passengers was on the other side of the equation!

Kind Regards, John
 
But it's not a matter of safety versus commercial interest. There is no real safety issue at stake here. Perhaps I'd given the wrong impression - there are others involved in the drafting of most product standards, including HSE and various consumer protection groups. BSI, like nearly all other publishers, do not have technical staff to review the content of standards. That is done by the members of the committee concerned.
Guess where I've been all week? ;)
 
I'm sorry to hear that you and BAS find it hard to understand.If they were not intended to carry 13A, why would they be marked 13A?
For a start, it's only a few days since you reminded me that a manufacturer's 'rating' means nothing unless qualified - e.g. in relation to the duration of load to which it refers, ambient conditions, mounting method etc.
Does a 32A MCB have a different rating when installed next to another? or, indeed, when it is fitted with a double or triple toggle as part of a two-pole or three-pole MCB?
Well, at least in some senses (and for at least some manufacturers) the short answer appears to be 'yes' ....
Mr Wylex said:
Adjacent thermal-magnetic MCBs should not be continuously loaded at or approaching their nominal rated currents when mounted in enclosures. It is good engineering practice to apply generous derating factors or make provision for adequate free air between devices. In these situations, and in common with other manufacturers, we recommend a 66% diversity factor is applied to the MCB nominal rated current where it is intended to load the MCBs continuously (in excess of 1 hour).

Kind Regards, John
 
I'm sorry to hear that you and BAS find it hard to understand.If they were not intended to carry 13A, why would they be marked 13A?
For a start, it's only a few days since you reminded me that a manufacturer's 'rating' means nothing unless qualified - e.g. in relation to the duration of load to which it refers, ambient conditions, mounting method etc.
Does a 32A MCB have a different rating when installed next to another? or, indeed, when it is fitted with a double or triple toggle as part of a two-pole or three-pole MCB?
Well, at least in some senses (and for at least some manufacturers) the short answer appears to be 'yes' ....
Mr Wylex said:
Adjacent thermal-magnetic MCBs should not be continuously loaded at or approaching their nominal rated currents when mounted in enclosures. It is good engineering practice to apply generous derating factors or make provision for adequate free air between devices. In these situations, and in common with other manufacturers, we recommend a 66% diversity factor is applied to the MCB nominal rated current where it is intended to load the MCBs continuously (in excess of 1 hour).

Kind Regards, John
Yes, I did remind you of that - so what? 13A is a rating that is not qualified by a descriptor such as "short-term", "single-outlet only", etc.

The Wylex quote refers to mounting in enclosures. In engineering terms, it is saying that the Ithe rating is less than the Ith rating.

Sorry about that lousy formatting, I'm busy backing-up the laptop before I hand it back tomorrow - I'm retiring, as of 31 Dec! :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL:
 
But it's not a matter of safety versus commercial interest. There is no real safety issue at stake here. Perhaps I'd given the wrong impression - there are others involved in the drafting of most product standards, including HSE and various consumer protection groups.
Yes, I understand all that, so maybe you did 'give the wrong impression', since it was you who wrote:
However, given that the manufacturers have no great incentive to give themselves more onerous tests to perform, the standard has not been updated in that respect.
...which seems to imply that the interests of the manufacturers resulted in the Standard not being updated, whatever other members of the relevant committees may have felt.
BSI, like nearly all other publishers, do not have technical staff to review the content of standards. That is done by the members of the committee concerned.
Indeed, but I don't think the general public would distinguish between the BSI (the 'publisher') and its committees. What matters to them is that whoever writes the Standard (the committees) are appropriately constituted so that commercial interests are not able to 'overcome' considerations of 'public interest' (e.g. 'safety') - which I imagine (hope) actually is the case..

Kind Regards, John
 
Yes, I did remind you of that - so what? 13A is a rating that is not qualified by a descriptor such as "short-term", "single-outlet only", etc.
So are you saying that, in the absence of such a qualification, it is being said that the outlet can tolerate 13A indefinitely - and, indeed, that if there are two such outlets on the same plate, they can both tolerate 13A indefinitely and simultaneously?
The Wylex quote refers to mounting in enclosures. In engineering terms, it is saying that the Ithe rating is less than the Ith rating.
Is a CU or DB not an 'enclosure'?
Sorry about that lousy formatting, I'm busy backing-up the laptop before I hand it back tomorrow - I'm retiring, as of 31 Dec! :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL:
Congratulations. They might at least have allowed you to keep the laptop :)

Kind Regards, John
 
Yes, I did remind you of that - so what? 13A is a rating that is not qualified by a descriptor such as "short-term", "single-outlet only", etc.
So are you saying that, in the absence of such a qualification, it is being said that the outlet can tolerate 13A indefinitely - and, indeed, that if there are two such outlets on the same plate, they can both tolerate 13A indefinitely and simultaneously?
The Wylex quote refers to mounting in enclosures. In engineering terms, it is saying that the Ithe rating is less than the Ith rating.
Is a CU or DB not an 'enclosure'?
Sorry about that lousy formatting, I'm busy backing-up the laptop before I hand it back tomorrow - I'm retiring, as of 31 Dec! :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL:
Congratulations. They might at least have allowed you to keep the laptop :)

Kind Regards, John
No, I am saying the opposite - if there is no qualifier, the rating might be extremely short-term, or continuous.

Yes, a CU or DB includes an enclosure, but again that wasn't my point. I was talking about adjacent MCBs, whether enclosed or not.

As for letting me keep the laptop, I've only worked there for 26 years! You should see the ancient Nokia mobile phone they're making me return. Mind you, they did let me buy a Ferrari to mark 25 years.
















However, it was only a wristwatch.
 

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