EICR - Hob and Oven Connections

[securespark]

I doubt it but overheated wire in a 3KW oven doesn't happen if protected according to MI's

Is installing to MIs still in the big book?

I thought it had been struck out.

 

[JohnW2]

Is installing to MIs still in the big book? ... I thought it had been struck out.

Still there, but MI's now only "have to be taken into account", whereas previously there was a requirement to 'obey' them

Kind Regards, John

 

[SUNRAY]

Ah yes but...

There is a difference between the regs circuit design requirements and the manufacturers instructions.

There is nothing to stop the manufacturer stating 'this component must be protected by...'. When it fails with an overload and wiring is overheated because of the lack of specified protection, I think they should have every right to refuse to replace/repair it under warranty, well at least the additional damage.

It's no different to tipping a vase of water into a TV.

And if the insurance company got involved they would payout on the TV accident but very soon dispute the overheating.

 

[JohnW2]

There is nothing to stop the manufacturer stating 'this component must be protected by...'.

Sure, manufacturers can write whatever they like, although I suspect that if some 'authority' discovered that a manufacturer had written something that was positively dangerous, they would probably have something to say about it

However the point is that, although it did in the past, BS7671 no longer 'requires one to 'comply' with' MIs.

Kind Regards, John

 

[SUNRAY]

Sure, manufacturers can write whatever they like, although I suspect that if some 'authority' discovered that a manufacturer had written something that was positively dangerous, they would probably have something to say about it

However the point is that, although it did in the past, BS7671 no longer 'requires one to 'comply' with' MIs.

Kind Regards, John

Let me try and make another comparison, If you purchase a jack for lifting cars and it has a 1 ton lifting capacity and it collapses, would you expect it to be repaired/replaced?

 

[ebee]

Let me try and make another comparison, If you purchase a jack for lifting cars and it has a 1 ton lifting capacity and it collapses, would you expect it to be repaired/replaced?

Well if you are lifting 1 ton or less by proper means I would say yes

 

[EFLImpudence]

...but what if the manufacturer stated that the jack must have a 3A fuse? Would you use it?

 

[SUNRAY]

Well if you are lifting 1 ton or less by proper means I would say yes

So you are happy to accept the manufacturers intructions to limit the load to 1 Ton in order to prevent damage to hydraulic seals and linkages etc but you are happy to ignore the manufacturers instructions to limit the current to 3A (example) with a fuse etc and I assume you would expect them to repair when damage is caused by the ommission?

 

[EFLImpudence]

Apples and oranges.

 

[SUNRAY]

Apples and oranges.

Please explain

 

[EFLImpudence]

Please explain

You are comparing things which are different and assuming the electrical device can or will be damaged if the 3A fuse is not fitted.



Why don't the manufacturers of your jack make it impossible to put more than 1 ton on it?

 

[SUNRAY]

You are comparing things which are different and assuming the electrical device can or will be damaged if the 3A fuse is not fitted.

Having been in the situation on more than one ocassion where an overload of an incorrecly installed circuit has occurred, I think it's only fair I can make such assumptions. I mentioned in a post fairly recently an oven in such a condition which the manufacturers maintenance agent very quickly established the cause and refused repair, in my opinion very justly.
As a manufacturer myself I have been called to site where the installer has got it very wrong and the resultant damage was proved to not be my responsibility. I have also been paid to generate reports for other similar failures, all of which have been easy to demonstrate whether it had been the manufacturers fault or the installers fault. Just as likely to be the designer/consultants fault, sometimes I can pinpoint that but it's usaully established higher up the chain after the technical reports.

Why don't the manufacturers of your jack make it impossible to put more than 1 ton on it?

They verywell may well do, on the other hand providing instructions to restrict the lift to 1 Ton is adequate as the operator has control on what they are lifting whereas the operator of an oven has no such control of the current it can draw, other than fiting the correct OCPD as instructed by the manufacturer.

 

[DetlefSchmitz]

The point is that anyone who manufactures and sells a piece of mains driven equipment is legally obliged that if that equipment fails internally it should not create damage outside itself that was preventable. Setting a house on fire because they wanted to save money on a fuse is not acceptable.

 

[SUNRAY]

The point is that anyone who manufactures and sells a piece of mains driven equipment is legally obliged that if that equipment fails internally it should not create damage outside itself that was preventable. Setting a house on fire because they wanted to save money on a fuse is not acceptable.

There is some truth in that, it can easily be achieved by selecting the correct fuse in the plug for example.

However there are some quite distinct demarcations on whether something is classed as an appliance or a component etc.

It is possible to specify the installation conditions, for example; to not fit a heat source pointing at or too close to a flammable surface. I don't see too many people advising others to ignore that one

As a component the lines are blurred, for example a transistor (ie the little 3 legged device) will have a data sheet available which in itself is essentially a set of instructions advising of maximum and minimum parameters between which the device will work correctly and without causing damage.
At that point one would not be expected to fit protection devices, instead that is left to the designer/installer to deal with. That component is then fitted into something, let's call it a power controller and sold to other companies to install in their products, and it will have a data sheet available which in itself is essentially a set of instructions advising of maximum and minimum parameters between which the device will work correctly and without causing damage. At that the power controller may be a PCB (printed circuit board) and is not a complete appliance, it is still a component and as such it does not require protection to be included. However it may very well require protection and any requirement would be included on the data sheet.
So the PCB is fitted by another manufacturer into the next stage of the production line, let's say they choose to install it in an oven to control the temperature. The oven will include a selection of other components from different manufacturers, such as a bulb holder, bracket and its lens/cover, a glass door and its fixing screws and captive, wire shelves and the runners to accomodate them etc. It is the oven manufacturers responsibility to ensure theat each of the components is suitable for the job and correctly used. At that time the manufacturer has made the decision the product is fit for purpose and procuces a data sheet which in itself is essentially a set of instructions advising of maximum and minimum parameters between which the device will work correctly and without causing damage.
At that stage the oven may be supplied with or without a connecting cable but no plug to another manufacturer to be fitted into a larger unit with more control units and things that get hot, let's call it a cooker and it is the cooker manufacturers responsibility to add whatever protection is required as listed on the data sheet, or after their thorough assessment they may make a decision to take the risk and not add protection. This is called risk assessment and performed by all of us on a regular basis without realising we are doing it for a lot of the time. The cooker manufacturer will make themselves responsible for any damage caused to the oven if they don't follow the advice given on the data sheet and in turn produce their own data sheet. Included in that will be the parameters for safe use, part of that will be current limiting.
Let's go back a stage and supply the oven with or without a connecting cable but no plug directly to the installer to be fitted into a shiny new kitchen, they accept the responsibility to use the oven in a way which conforms to the parameters listed in the data sheet and part of that may very well be the method of limiting the current draw, the installer adds follows all of those parameters or after their thorough assessment they may make a decision to take the risk and not do so, such as not providing the required ventilation or adding electrical protection. This is called risk assessment and the installer will takeover the responsibility for anything they have not followed on the data sheet.

So far everything I've described is a component, without the 13A plug it is not an appliance and therefore doesn't come under the umberella of

...legally obliged that if that equipment fails internally it should not create damage outside itself that was preventable. Setting a house on fire because they wanted to save money on a fuse is not acceptable.

any requirement/recommendation is to be added by the next stage of manufacturing which happens to be the installer or electrician in accordance with the paperwork supplied unless their risk assessment is such that they think the information supplied can be ignored, in which case they are obliged to accept responsibility for failures.


My manufacturing has primarily been building control panel to order and to the drawings provided, I'd do the circuit designs, broadly limited to sizing wiring. It would then go to site and be installed by the electricians and I'd often follow up with site visits to correct the mistakes (lots of) made by the electricians and/or make alterations if required.

 

[JohnW2]

Let me try and make another comparison, If you purchase a jack for lifting cars and it has a 1 ton lifting capacity and it collapses, would you expect it to be repaired/replaced?

Specifications and "MIs" are surely two totally different issues, aren't they?