220v. 230v, 240v, 250v?

[John-SJW]

I saw an oven that was rated at 3,100 watts. Now most would say that cannot be fitted on final ring circuit as rule of thumb. But:
3,100 watts draws amps of:
14.09 amps @ 220v
13.47 amps @ 230v
12.91 amps @ 240v
12.4 amps @ 250v

If the installation is 240v or 250v then it safely inside the 13 amp of a final ring circuit.

The question is, and the regs aficionados can help here, what is the voltage that should be used to assess, as maybe the voltage will vary in an installation over the years.

 

[Julie.]

Remember the terms "close excess protection" and "coarse excess protection" (not sure if they are used much any more). But manufacturers would be aware that most fuses are pretty crude devices. ....

Course protection was essentially a rewirable fuse (and cartridge fuses q2 or R class), and close protection was a cartridge fuse, the terms were removed when the cable sizing method was revamped and the single rated value used for fuses, mcb... etc. Rather than a different value for each type of device based on the 1.5x over 4 hours.

I think it was removed in the 15th edition, but could have been 16th

 

[ipf]

Coarse protection was essentially a rewirable fuse (and cartridge fuses q2 or R class), and close protection was a cartridge fuse, the terms were removed when the cable sizing method was revamped and the single rated value used for fuses, mcb... etc. Rather than a different value for each type of device based on the 1.5x over 4 hours.

I think it was removed in the 15th edition, but could have been 16th

I thought it was after the 16th, when we had the infamous 'bond everything' theory but I now reckon it was 'removed' by the 15th. Found a 1981 Whitfield Guide to 15th with no mention of 'close and coarse'....just HBC, MCB and rewireable.
For cable ratings, certainly in the 14th, it was a case of 'the ratings tabulated
may be multiplied by 1.33 where close excess current protection can be assured'. For some larger cables it was the other way round (x 0.75), because of HBC protection. For others (larger supply cables, generally) ratings were the same for both.
No cable tables for the 15th but it may have been where tabulated values became all 'close'.......?

 

[Lucien Nunes]

manufacturers would be aware that most fuses are pretty crude devices. A 13 amp fuse will happily carry 15,16 amps for more than enough time than it takes to cook your chicken

I think this is a slightly disingenuous observation on fuses. And a reputable manufacturer would not exploit a known undesirable situation (non-tripping overload of OCPD). So I still contend that the hob in question is not supposed to be set to deliver 3.7kW from a 13A plug.

 

[LastManOnline]

I think this is a slightly disingenuous observation on fuses

I think you "slightly" misunderstood. My reference was to how an appliance manufacturer would be aware of the tolerance of 13 amp fuse. Disingenuous??

. And a reputable manufacturer would not exploit a known undesirable situation (non-tripping overload of OCPD).

Of course he would, nt. That's why he is known as reputable. The OP clearly had some doubts about this particular manufacturer. The"badlyworded" English (you highlighted in jest), in the instructions will does little to inspire a consumers confidence.

. So I still contend that the hob in question is not supposed to be set to deliver 3.7kW from a 13A plug.

You are entitled to your contention. But it does not harmonize with the stated manufacturers instructions as displayed by the OP.

"The plug limits the maximum power output 3.7KW" is badly worded but as DPG stated, the intent is clear and...... incorrect

 

[Lucien Nunes]

The appliance that I was referring to was made by/for a large, reputable, European HQ'd manufacturer whose brands account for a good fraction of mid to high-end UK appliance sales. My observation was specifically that it seems more likely that the literature and specification is in error, at least in the English version, than the design of the appliance.

My reasoning is that the error appears to be of a form that often occurs when different versions of a product are marketed to different territories with different versions of instructions. Sections that need to be replaced altogether to account for version differences are sometimes translated instead. Here, I suspect that the difference between the maximum power input permitted in the UK and German versions has been overlooked when compiling the English instructions.

E.g. where a German manual instructs the user to connect the appliance to a 16A Schuko socket, the English might say 'Connect the appliance to a 16A safety contact'. The incorrect wording 'safety contact' is a clue that a section of text that should have been replaced outright with 'Connect the appliance to a 13A socket-outlet' has instead been translated, therefore the reference to 16A might also be a mistake. Just as I routinely find instructions for US-made, CE-marked, 230V-compatible gear sold in the UK to use only a UL-listed cordset to connect it to my 120V grounded receptacle.

In summary, I do not think it was the intention of Bosch to imply that a 3.7kW load may be supplied via a 13A plug, and therefore to flag it as bad design and blame such a practice for damage and failure would require verification as to whether that really was their intention. If so, then I agree fully that it is bad design.

 

[static zap]

If so, then I agree fully that it is bad design.

i take it as a cheeky prod , Our EU 16A is bigger than your inferior 13A.
(though you are fused down inherently safer ,and more efficient)

 

[John-SJW]

The appliance that I was referring to was made by/for a large, reputable, European HQ'd manufacturer whose brands account for a good fraction of mid to high-end UK appliance sales. My observation was specifically that it seems more likely that the literature and specification is in error, at least in the English version, than the design of the appliance.

My reasoning is that the error appears to be of a form that often occurs when different versions of a product are marketed to different territories with different versions of instructions. Sections that need to be replaced altogether to account for version differences are sometimes translated instead. Here, I suspect that the difference between the maximum power input permitted in the UK and German versions has been overlooked when compiling the English instructions.

E.g. where a German manual instructs the user to connect the appliance to a 16A Schuko socket, the English might say 'Connect the appliance to a 16A safety contact'. The incorrect wording 'safety contact' is a clue that a section of text that should have been replaced outright with 'Connect the appliance to a 13A socket-outlet' has instead been translated, therefore the reference to 16A might also be a mistake. Just as I routinely find instructions for US-made, CE-marked, 230V-compatible gear sold in the UK to use only a UL-listed cordset to connect it to my 120V grounded receptacle.

In summary, I do not think it was the intention of Bosch to imply that a 3.7kW load may be supplied via a 13A plug, and therefore to flag it as bad design and blame such a practice for damage and failure would require verification as to whether that really was their intention. If so, then I agree fully that it is bad design.

Was the Bosch induction hob installer settable from 3Kw to 3/7kW? The instructions were wrong for sure.

The British 13A plug is inferior? I have not seen any plug/socket arrangement that is better. None. The earthed Schuko socket with a 13A fuse in the plug would be a great advancement being something the British could take up creating some sort of standardisation. I like the idea of drilling only a round hole to fit a socket.

 

[DPG]

Was the Bosch induction hob installer settable from 3Kw to 3/7kW? The instructions were wrong for sure.

The British 13A plug is inferior? I have not seen any plug/socket arrangement that is better. None. The earthed Schuko socket with a 13A fuse in the plug would be a great advancement being something the British could take up creating some sort of standardisation. I like the idea of drilling only a round hole to fit a socket.

Did he say the British 13A plug is inferior?

 

[nicebutdim]

Did he say the British 13A plug is inferior?

Possible that something was lost in translation, but I understood Lucian to mean that the hob's design could be considered poor if it could be verified that Bosch's intention was to supply the full 3.7kW load through a 13A plug - he didn't believe this to be the case.


Edit: Have I just taken the bold step of attempting to clarify a point made by Lucian? Better get my coat...

 

[static zap]

British 13A plug is inferior?

Only on a playground dispute ,my number is bigger than yours basis ,
(But I still have my Eurovision bitterness to deal with)

 

[ipf]

Only on a playground dispute ,my number is bigger than yours basis ,
(But I still have my Eurovision bitterness to deal with)

Eurovision twitterness, don't you mean ?.

 

[LastManOnline]

Did he say the British 13A plug is inferior?

No he did, nt. But since the topic has been raised, here is my tuppence worth about which is superior. I hold the standard British and Schuko plugs in high regard. (not cheap knockoffs of either) . Have used them both extensively. I would say that on balance I prefer the British plug, specifically for its flat "wall hugging" design with a "vertical" rather than "horizontal" lead. It's much easier to hide.

 

[LastManOnline]

The British 13A plug is inferior? I have not seen any plug/socket arrangement that is better.

The British 13amp plug is not, as many British people seem to believe, inherently safer because of its 13 amp fuse. It seems to be perceived as an"extra" that other countries plugs don't have. The reality is, is that these fuses are the price that has to be paid for employing a 32 amp ring circuit rather than a 16 (or 20amp) radial.

None. The earthed Schuko socket with a 13A fuse in the plug would be a great advancement

The "schuko" is already an advanced version of the British plug regarding not needing any fuses

the British could take up creating some sort of standardisation.

If you are hoping the rest of the world will adapt the British fused plug................. Best of luck....... you will need it.......

 

[DPG]

I remember reading some articlet which discussed and tested the various mains plugs. I think the British 13A plug excelled in every respect bar one.

Any offers for what test it failed on? No prizes though!

 

[littlespark]

I remember reading some articlet which discussed and tested the various mains plugs. I think the British 13A plug excelled in every respect bar one.

Any offers for what test it failed on? No prizes though!

likelihood of injury by stepping on a plug barefoot, pins up?

 

[DPG]

likelihood of injury by stepping on a plug barefoot, pins up?

No, but that's a very good one. Along with bits of Lego obviously!

 

[John-SJW]

The British 13amp plug is not, as many British people seem to believe, inherently safer because of its 13 amp fuse. It seems to be perceived as an"extra" that other countries plugs don't have. The reality is, is that these fuses are the price that has to be paid for employing a 32 amp ring circuit rather than a 16 (or 20amp) radial.


The "schuko" is already an advanced version of the British plug regarding not needing any fuses

If you are hoping the rest of the world will adapt the British fused plug................. Best of luck....... you will need it.......

Having a local fuse to a single socket outlet is a great advantage and safety feature. Nothing is better than the UK 3-pin plug, nothing. It is also easy to hold, not like other small awkward plugs around the world, so fine for user use. Get to understand its merits.

 

[John-SJW]

I remember reading some articlet which discussed and tested the various mains plugs. I think the British 13A plug excelled in every respect bar one.

Any offers for what test it failed on? No prizes though!

In the late 1980s there was talk of a standard Euro plug that would all adopt. I recall a small 5 minute film on Channel 4 by an American involved in the film industry. He was lauding the UK 3-pin plug, pointing out its advantages, especially the local fuse in the plug, and a firm engagement when pushed in, that would not fall out, saying it is by far the best in the world.

He based this on working around the world experiencing different electrical systems. He said he bought a whole bunch of UK plugs, fuses and plugboards to use on his own equipment when touring the world. If one piece of equipment was at fault, it never took the lot down.

He was strongly recommending the British not to take up an inferior design and that the EU should adopt the best plug, not adopt an inferior design.

 

[DPG]

In the late 1980s there was talk of a standard Euro plug that would all adopt. I recall a small 5 minute film on Channel 4 by an American involved in the film industry. He was lauding the UK 3-pin plug, pointing out its advantages, especially the local fuse in the plug, and a firm engagement when pushed in, that would not fall out, saying it is by far the best in the world.

He based this on working around the world experiencing different electrical systems. He said he bought a whole bunch of UK plugs and fuses to use on his own equipment when touring the world. If one piece of equipment was at fault, it never took the lot down.

He was strongly recommending the British not to take up an inferior design and that the EU should adopt the best plug, not adopt an inferior design.

Yes, I remember the talk about the standard Euro plug. It's good that they forgot about it!

Nobody has picked up the one test which the British plug fails when compared to US and some other plugs though.

 

[John-SJW]

I do not believe the US plug has any advantages over anything anywhere.

 

[DPG]

I do not believe the US plug has any advantages over anything anywhere.

There is one advantage.

 

[nicebutdim]

Only downside I can think of is its aesthetics - not pretty, but robust and functional.

 

[DPG]

Only downside I can think of is its aesthetics - not pretty, but robust and functional.

One of the things they considered is a common occurrence - what happens when someone trips over the flex, eg when hoovering etc.

With the US plug, and others which also have the cable exiting horizontally, is that the plug just pulls out of the socket. No harm done.

With the UK plug, because the cable exits at the bottom, the plug does not pull out. What happens is that the flex gets partially ripped out of the plug, and sometimes damage occurs to the plug and even possibly to the socket.

I don't know of any other disadvantages and, like John, I think the British 13A plug is an excellent design generally.

 

[LastManOnline]

Having a local fuse to a single socket outlet is a great advantage and safety feature.

Perhaps you misunderstood my previous post. The fuse in a British plugtop HAS to be there due to the design of the ring circuit. It's a NECESSARY feature for the protection of the appliance cable connected to it.

This extra safety feature is generally not a requirement on European 16 amp radials

 

[Rockingit]

I've a flightcase full of global anything to anything adaptors, and there's good and bad in each one. We're stuck with a fused plug due to the RFC, and we're stuck with the RFC as a left over from scarcer times. Apart from the guarded outlets in the sockets there's little to be gained by our design - over engineered and cumbersome. The Australian one is pretty good.

 

[LastManOnline]

He said he bought a whole bunch of UK plugs,.... If one piece of equipment was at fault, it never took the lot down.

Not "taking the whole lot down" is a good reason for using local fuse downsizing. But this is a very different reason from the primary reason British plugs have fuses... without them circuit safety would be compromised. They are a necessity, not an option.
I would suggest to the American in question that he try using more radial circuits.

 

[John-SJW]

Not "taking the whole lot down" is a good reason for using local fuse downsizing. But this is a very different reason from the primary reason British plugs have fuses... without them circuit safety would be compromised. They are a necessity, not an option.
I would suggest to the American in question that he try using more radial circuits.

I would assume his portable film equipment was all radial. The fused 3-pin was to accommodate rings for sure - and to offer other safety spin-offs which were all thought out, not incidental.

 

[John-SJW]

This extra safety feature is generally not a requirement on European 16 amp radials

That is why they are not as safe as British systems.

 

[John-SJW]

I've a flightcase full of global anything to anything adaptors, and there's good and bad in each one. We're stuck with a fused plug due to the RFC, and we're stuck with the RFC as a left over from scarcer times. Apart from the guarded outlets in the sockets there's little to be gained by our design - over engineered and cumbersome. The Australian one is pretty good.

You need to think it all through.

 

[John-SJW]

Only downside I can think of is its aesthetics - not pretty, but robust and functional.

Two plugs. One white one black. Available in any colour in fact. They are ugly to what we see elsewhere? Please.

 

[Rockingit]

You need to think it all through.

Say what?!

 

[DPG]

The whole shutter design and the design of the contacts in the UK plug and slcket is very good. The cord grip of the plug works well, and there is plenty of room for termination.

As I say, I think it's the best of the lot.

 

[Rockingit]

The whole shutter design and the design of the contacts in the UK plug and slcket is very good. The cord grip of the plug works well, and there is plenty of room for termination.

As I say, I think it's the best of the lot.

That’s what I said…. Except, thanks to Esther Ranson the end user should never need to know about termination and cord grips anyway

 

[DPG]

That’s what I said…. Except, thanks to Esther Ranson the end user should never need to know about termination and cord grips anyway

Ooh careful, we'll be entering into the whole 'you can't cut plugs of cos it voids the warranty' thing!

And can I just say the word 'plugtop'. Ta.

 

[Rockingit]

This thread has reminded me that I need to PAT most of the contents of said flightcase! At least I can do it with a cider by my side later. Actually, I'll have to, as I think that case is currently acting as a bench for the home-made....

 

[John-SJW]

Ooh careful, we'll be entering into the whole 'you can't cut plugs of cos it voids the warranty' thing!

And can I just say the word 'plugtop'. Ta.

But the instructions say consult an electrician, who deemed it should be cut off, so all is well.

Plugtop? What a silly term.

 

[DPG]

But the instructions say consult an electrician, who deemed it should be cut off, so all is well.

Plugtop? What a silly term.

That's two plugtops now. Don't forget what happens on the 3rd one ?

 

[Lucien Nunes]

In the late 1980s there was talk of a standard Euro plug that would all adopt.

This was IEC 60906. It is a good, compact design of plug following European practice with certain incremental improvements locked in, similar in layout to the Swiss SEV1011 which is based on the usual 4-4.8mm pins on 19mm centres but with an offset earth pin.

IEC 60906-1 was later taken up by Brazil and SA in 10, 16 and 20A versions, but failed in Europe. There was insufficient commercial benefit to standardisation, not least because a significant proportion of low-load class II items come fitted with 2.5A Europlugs which are already pan-EU compatible.

I was a keen teenage inventor at the time and I had a go at solving the remaning compatibility problems for 60906 for the UK. The elephant in our particular room is the lack of OCPD required for backward compatibility with 32A circuits. This I solved with value-added features by replacing the socket switches with MCBs. The socket itself is small enough that a UK back-box has space for a version including the MCB(s). The MCB was also interlocked with the plug so that it would only switch on with a plug inserted, and I had a version that would set the thermal trip current according to the shape of the plug. Insert a Europlug or 3-pin plug with a keyway, and the breaker would set to a lower value than with the full size 16A plug inserted.

It worked, but at the time it was too expensive and no-one wanted to take it on. But FWIW the MCB-equipped socket is available from Bticino in CEI 23-50 form. Today I think it would be cost-effective but there's not the interest in 60906 that was buzzing then.

• 16A allows a good safety margin on 3kW
• Contacts designed for continuous operation at 13..5A for life of product
• Can be connected to circuits up to 63A rating
• Fully touch-proof / interlocked / child-safe
• Up to 4 outlets in normal dual-gang box
• Compatibility with 2-pin Europlug
• Sleepwalker-friendly!

It was my attempt to take the best of European and British and combine them into one product with no geographical limits or undesirable compatibility issues. Anything that fits it, is safe to use in it.

 

[John-SJW]

This was IEC 60906. It is a good, compact design of 16A plug that follows from European practice with certain incremental improvements locked in, similar in layout to the Swiss SEV1011 which is based on the usual 4.8mm on 19mm centres but with an offset earth pin.

IEC 60906-1 was taken up by Brazil and SA, but failed in Europe. There was insufficient commercial benefit to standardisation, not least because a significant proportion of low-load class II items come fitted with 2.5A Europlugs which are already pan-EU compatible.

I was a keen teenage inventor at the time and I had a go at solving the remaning compatibility problems for 60906 for the UK. The elephant in our particular room is the lack of OCPD required for backward compatibility with 32A circuits. This I solved with value-added features by replacing the socket switches with MCBs. The socket itself is small enough that a UK back-box has space for a version including the MCB(s). The MCB was also interlocked with the plug so that it would only switch on with a plug inserted, and I had a version that would set the thermal trip current according to the shape of the plug. Insert a Europlug or 3-pin plug with a keyway, and the breaker would set to a lower value than with the full size 16A plug inserted.

It worked, but at the time it was too expensive and no-one wanted to take it on. But FWIW the MCB-equipped socket is available from Bticino in CEI 23-50 form. Today I think it would be cost-effective but there's not the interest in 60906 that was buzzing then.

The problem is that if we wanted safety all over the EU, they would have to adopt the British/Irish/Cypriot 13A-fuse-in-the-plug approach. The UK inserting a fuseless plug on the millions of rings in the UK spells many fires and deaths.

The reality is that no common domestic appliances these days need more than 13amps, as efficiencies have risen. An EU directive could have gone out to ensure no new appliances consuming more than 13A. Having a fuse in the plug is an added safety feature even on radials.

In short, change the socket/plug shape and pins if you want (nice to have sockets where you only drill a large hole to fit), but a max of a 13A fuse must be in the plug.

 

[Lucien Nunes]

The point of my post was to illustrate how it can be got out of the plug, with consequential cost and space saving on the plug side and reduced heat dissipation, without losing the advantages of local OCPD.