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electric cooker hob


fulham sparks

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fulham sparks

went around to a job today where an electric cooker hob only had two of four working.. i flipped the hob over to uncover a 1.5 flex feeding the hobs!! there was a bridge between where the feed was terminated to a terminal to the right of it. I don't know the power rating of the hobs but as it's not a big unit i think a 6mm should be ok. I haven't fitted on of these hobs before so if anyone could give me some tips i would be grateful. cheers

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Andy™

each plate will only be 2.5kw (usually 2kw) max, so well within the capacity of 1.5

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fulham sparks

that gives a current of 43.7amps andy, 1.5 can only handle a max of 13 depending on c,i,g,a,r

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Andy™

are you on about the internal wiring to the faulty plates of the entire unit?

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Andy™

TP in a domestic.... wonder how many are wired that way

and what if the cable runs through insulation? may need 10mm or even 16mm

there is no 'one size fits all' cable for cookers.

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Sidewinder

Berlioz,

Can you please explain your abbreviations, and how you have come to the conclusion that every cooking appliance requires the same supply cable to comply with BS7671 when there are probably 100's of different combinations of cable type and installation method, without the 1000's of cooking appliances on the market that would require consideration.

Also, you seem to be suggesting 3ph 400V ac supplies for domestic cooking appliances, these extremely rare in domestic installations in the UK.

Once you start to factor in commercial and industrial cookers there are probably millions of combinations of cable size installation method and appliance to consider.

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To Sidewinter. Well, it easy. On the Lithuanian (and thats means on the Europian) market theres no domestic (for rezidential houses) cookers more than 7kW. All the modern cookers allower connecting 1ph (in my previous post 1F, sorry) and 3ph (the connecting scheme is shown as a rule on the back side). Lets account: 1ph. I=7/0.22=32A. Cable 3x6. 3ph=7/0.66=11A cable 5x2.5. If the cooker is specifical (more 7kW)-Customer should report me. Most of the cooker now are connected 3ph.Why? Well... emagine-Your house or flat has 10kW of permitted power. The automatic swith is 20A, 3ph. And Your cooker is 6kW, 1ph. I=6/0.22=27,2A. Now if the cooker is turned on at full power-Your permitted automatic switch will swith off after... 27.2A/20A=1.36 1.13<1.36<1.4... about 1 h. Is it good? No. Thats why we use 3ph connecting. I v been to GB (as a turist) and noticed that devices and aprouches very much differ from Europinian.

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Sidewinder

Berlioz,

There is then a huge difference between the EU & UK situation.

As very few of the members on here have worked to any other electrical installation codes of practice, then no one would have any experience of the situation in Lithuania, also, as it bears no resemblance to the UK regulations then as far as UK cookers go your advice is incorrect.

Our regulations have just been updated and the new set will come into effect on 1/1/12.

This retains our ability to write national standards requirements into the IEC standard, thus our regulations will also continue to be somewhat different.

It is rare on this forum that we consider installations outside the UK, as the forum and its members are UK based and concentrate on our domestic market.

A few members have worked overseas (from our point of view) and, this is in various locations and with various other types of installation and equipment.

Personally I have never done building installations wiring outside the UK, I have worked on machinery etc. from overseas and when overseas, however I have no experience of your mainland European cooker installation standards, also it will be quite a while before these things are harmonised into the UK.

Therefore really your comments on the fact that it is easy to install a cooker and that you should just use 2 standard circuits are not relevant in the UK.

Also from what I can understand of your 2 posts I don't believe that your less than rigorous approach meets the IEC standard, which I have previously had access to along with some equipment manufacturers guidance on compliance with that standard, and your approach seems much too simplistic to meet even the rudimentary requirements of that standard.

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Well, Sidewinder. All modern regulations as GB as Europian (and Lithuanian correspond to Europian) are completely based on IEC standart. Ant the Om and Kirhchoff lows (or principles?) are alike. Differ only traditions and divices. You ll never see such a luminare switches or sokets as you use in Europe. And at whole-the domestic devices gamma in Europe is much wider than in GB. But you never know-when you ll werk tomorrow. I had a nice oportunity to werk with americans drawings (it was Am ambasada). I had to adopt them to Europian standarts (or traditions if you like) and to translate. May be tomorrow I ll werk with GB drawings. I am electric designer. By the way-on this forum I see only erectors (sparks, as you say), but not designers. Where are your designers? May be they are too smart to ask questions? :) May be you have one or another simple electrical project to send me? That woud be fantastic. Thank you for your post.

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Sidewinder

Berlioz,

I am a qualified engineer I work freelance doing electrical & mechanical designs myself, however I choose also to install and build my own designs.

I am sufficiently qualified to practice as a professional engineer in Europe and many other countries in the world even where a licence is needed to practice.

I chose my own destiny what I do and who my customers are.

I have a group of reliable suppliers and sub-contractors I can utilise as I choose.

I am fully aware of the basis of BS7671 on the IEC standard, as I teach the wiring regulations and the inspection & testing of installations qualifications.

I also understand ohms law, the Kirchoff laws and several other fundamental laws of science.

The UK regulations differ in more than just traditions and devices.

By the way I appreciate that English is not your first language, but I do find your posts difficult to understand, which is made worse by your typographic style.

The NEC which is prevalent on the American continent differs quite a bit from the IEC standards, and both differ from BS7671.

We impart many of our own regulations onto the standard, this has become even more transparent with the last amendment in the re-numbering of our UK national regulations to make them stand out from the IEC harmonised regulations.

If you are as you say a designer then I am disappointed that you undertake such a simplistic calculation of circuit loading without considering any external influences on the installed circuit.

As I understand things there are differing installation methods in the IEC standard, and there are influences of insulation of cables and other such de-rating factors included, thus these must be considered to ensure that you have a safe and compliant design.

Electrical designers in the UK tend to work on larger projects. Small domestic, commercial and industrial works are normally designed, installed, inspected and tested by the installer, as this is taught during their training.

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Andy™
On the Lithuanian (and thats means on the Europian) market theres no domestic (for rezidential houses) cookers more than 7kW.

well, that 10.5KW cooker i fitted today must be illegal then, even though it was brand new!

i suggest you go find a lithuanian forum and go there instead of telling us how we are doing thins wrong because its not how your country does it

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fulham sparks

right! no offence berlioz but i'm going to have to ignore everything you say lol!! i went around there today and found a few things which i didn't have time to look at on my first look.

1. the cooker and hob are fed from a 32a ring mcb (no rcd protection on board at all)

2. the feed from the isolater to the outlet is in 1.5mm2, then it was in 1.5mm2 to the terminals under the hob from the outlet.

3. out of 4 hobs only two (left side of the hob) work

i know cookers should be on their own circuit but the woman just wanted a quick fix. i'm guessing that either the cable size coming from the board is not large enough not allowing enough current to pass OR the elements have gone on the right hand side of the hob? the woman said all elelments worked when it ran on a 1.5 from the isolater for a while but now only the two work...

any ideas on what i should do would be great!

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Andy™

sounds like failed elements

could also be wired wrong at connections to cooker (may not have a link in place)

1.5 is no good and should be changed

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steptoe

here is one for you to design Berlioz,

easy for you

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fulham sparks

nah the link is there and that's in 6 mm lol! i reckon it's faulty elements too, told here to phone up and get one of their people out. cheers for the reply!

---------- Post Auto-Merged at 19:50 ---------- Previous post was made at 19:39 ----------

steptoe what exam was that question for? please don't say 2391 ? :|

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fulham sparks

i'm studying for my 2391 at the moment so not much time to have a stab at it right now. not great with the old smiley face things so were you being sarcastic with that beng a 2391 level question?

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steptoe

that would be around that level of question fulham,

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