I have not waded through all eight pages so if this has been said before my apologies, gas boilers in the uk have to be installed to bs 7671(or whatever electrical regs the manufacturers stipulate) and all the relevant gas regs, I don't have access to bs7671 so take the manufactures instructions as being correct, ie fcu or plug with 3 amp fuse.
3 amp fuse in FCU for boiler
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Quite so. A problem which arises IF a manufacturer 'requires' something which is not actually necessary is that it can help to perpetuate unnecessary practices, whether they result from habit, 'tradition', ignorance, misunderstanding of regulations of whatever.
Consider, for example, a situation in which a manufacture of a boiler 'required' that all pipes connected to it should be 'cross-bonded'.
Kind Regards, John
The requirement (as a generalisation) certainly doesn't come from BS7671 - so, if it does relate to a regulation, it must be a gas one, and no-one seems to know about that for sure.
The possibility being discussed is that manufacturers may be imposing 'requirements' which are not actually required by any regulation - gas, electrical or whatever.
Kind Regards, John
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That's what we're discussing.
There is nothing in BS7671 which would demand a 3A fuse for cables that didn't require it, nor does it concern itself with appliances.
No one seems to know if the gas regulations demand it, whether validly or not, although it is difficult to think of a valid reason why they should.
Manufacturers tend to state such things without much regard to anything, so cannot be relied on for being correct.
Plus, as we keep saying, these appliances - whether whole CH systems or single extractor fan - are installed in Europe where they don't have 3A fused connectors or plugs.
Maybe we could, if we had a parliament that had time for that, which we don't - at the moment they haven't even got the time to sort out the catastrophic act of lunatic national self-harm they made happen.
Indeed - in this case.
In this case I can see no further point to it.
510.3 Every item of equipment shall be selected and erected so as to allow compliance with the regulations stated in this chapter and the relevant regulations in other parts of BS7671 and shall take account of manufaturers' instructions.
The following comes from a Vailant EcoTec plus installation manual.
'The boiler is supplied for connection to 230 V, 50Hz supply fused at 3A rating. Connection to the mains supply shall be made via a 3 pin plug to an unswitched shuttered socket, both complying with the requirements of BS1363. (Alternatively, connection may be made via a 3A fused double pole isolator having a contact opening of at least 3mm in all poles and supplying the boiler and all controllers only). The point of connection to the mains supply must allow complete electrical isolation of the boiler and its ancillary controllers. It should be readily accessible and adjacent to the boiler. A 3 core flexible cord according to BS6500 tables 6,8 or 16 (3 x 0.75mm² to 3 x 1.5mm²) should be used.......'
Regards
The following comes from a Vailant EcoTec plus installation manual.
'The boiler is supplied for connection to 230 V, 50Hz supply fused at 3A rating. Connection to the mains supply shall be made via a 3 pin plug to an unswitched shuttered socket, both complying with the requirements of BS1363. (Alternatively, connection may be made via a 3A fused double pole isolator having a contact opening of at least 3mm in all poles and supplying the boiler and all controllers only). The point of connection to the mains supply must allow complete electrical isolation of the boiler and its ancillary controllers. It should be readily accessible and adjacent to the boiler. A 3 core flexible cord according to BS6500 tables 6,8 or 16 (3 x 0.75mm² to 3 x 1.5mm²) should be used.......'
Regards
Indeed, and that's a relatively recent change. It originally said that one must adhere to manufacturer's instructions. Now, we only have to "take them into account". That means that one can exercise discretion, based on knowledge and skill, to deviate from what a manufacturer has 'instructed'.
I think that change was probably needed because, although it shouldn't be the case, some MIs are just plain wrong, particularly when they have been inexpertly translated from some language in which someone (who didn't necessarily know what they were talking about!) wrote them.
Kind Regards, John
We already know that boiler makers say that - that is not in dispute.
Quoting from that manual does not advance our knowledge, it does not explain why they say that.
Do they say it because the UK gas regulations require it?
Or do they say it because they have made a product which is not safe to use on a supply fused at more than 3A?
If the latter, what happens in countries where FCUs and fused plugs are not used?. That is still unanswered, and will never be answered by quoting what they say in UK installation instructions.
https://www.vaillant.be/telechargem...cotec-proplus-0020010964-05-be-fr-1140206.pdf
I point to another thread recently
When are you going to understand enough to realise that if a manufacturer says that a product needs a 3A fused supply in this country it is valid to ask why that same product does not need it in other countries?
Do the boiler manufacturers state that it doesn't need a 3A fuse in other countries?
In my experience the MI's don't change just because they are in a different language.
And please no more about 16A shuko's on 16A MCB's in this situation.
The question, actually, is do they say that it is required? And then, if they do, then how do they say it should be provided, and if they don't then why do they say it is required here?
Don't be ridiculous - of course they do.
You don't need to have any knowledge of what those in other countries say to know that they won't say things like these:
'The boiler is supplied for connection to 230 V, 50Hz supply fused at 3A rating. Connection to the mains supply shall be made via a 3 pin plug to an unswitched shuttered socket, both complying with the requirements of BS1363. (Alternatively, connection may be made via a 3A fused double pole isolator having a contact opening of at least 3mm in all poles and supplying the boiler and all controllers only). The point of connection to the mains supply must allow complete electrical isolation of the boiler and its ancillary controllers. It should be readily accessible and adjacent to the boiler. A 3 core flexible cord according to BS6500 tables 6,8 or 16 (3 x 0.75mm² to 3 x 1.5mm²) should be used.......'
Why not, if the maker says that his boiler can be supplied by a 16A circuit in Germany but not in the UK?
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