Boiler wiring question

[ban-all-sheds]

Yes, but it does not specify a minimum.

Neither does 559.5.1.204.

Not in the same way.

Sorry, yes, in exactly the same way.

It's a mathematical relationship, and "not greater than", is, has always been, and will always be, equivalent to "less than or equal to". It simply cannot be otherwise.

If I am wrong, then so must be MI's which state just a maximum.

What about wiring regulations which state just a maximum?

 

[JohnW2]

Yes, but it does not specify a minimum.

I have addressed that. However, maybe you haven't seen what you wrote, which was ...

.... I don't think that ≤ is the same as maximum.

... which, as BAS has pointed out, is just plain wrong.

Kind Regards, John

 

[EFLImpudence]

What about wiring regulations which state just a maximum?

Ok. If that; according to you two, like ≤; includes fuses of too small a rating to allow the appliance to work, then it cannot be a correct instruction, can it?

 

[JohnW2]

Ok. If that; according to you two, like ≤; includes fuses of too small a rating to allow the appliance to work, then it cannot be a correct instruction, can it?

As said, it cannot be a sensible instruction. However, it is 'correct' in terms of the provision of adequate protection.

Kind Regards, John

 

[ban-all-sheds]

Well, it does include it. It cannot be otherwise.

But I would contend that using a device which was too small, when you could use one which was not too small and which still complied with 559.5.1.204 would be a contravention of other regulations.

does not mean that you have to use one which is the most below 3A that you can find, nor does it give you permission to use one so small that the equipment won't work.

Were they to have made something which would not work with a 3A fuse then there would be a problem with complying.

But if it won't work with a 1A fuse, or a 2A fuse, use a 3A one. Simples.

 

[ban-all-sheds]

As said, it cannot be a sensible instruction.

It can be, if you assume that people reading, and working to, the regulations are sensible.

 

[JohnW2]

Never assume!

 

[EFLImpudence]

We are now discussing the fact that one manufacturer states "≤3A" in a thread where we are arguing that the "3A" is not necessary in the first place.
That trial and error or exact knowledge of the construction is required to determine the minimum does not seem satisfactory to me.
An instruction of "maximum 16A" was introduced and is thought to be of identical meaning (apart from the number, obviously).
Accepting that you are correct, are there any which do state a "maximum rating"? If so are they correct and why do they state it?
[or is it, as with ovens, a confusion between 16A supply required and 16A OPD required even though 13A will do in Britain?]

While discussing MIs which are thought to be unreliable, why would any manufacturer state a maximum, or ≤, fuse rating for their product? Why not state the necessary correct rating for it to function and, if needed, be protected.
If a fuse rating higher than needed for functioning is allowed, presumably the innards have been made larger than necessary. Why would they do that?

For example, a boiler which needs 1A to function but has been made to withstand an overload (if possible) such that a 3A fuse will protect it may just as well demand a 1A fuse. If it can't cause overload then, as we have been saying, there is no need for the 3A requirement at all.

Incidentally, does anyone think a boiler would be damaged by fitting a 4A fuse or is it a coincidence, cooperation or standardisation that all boilers supposedly require 3A protection.

All this leads me to think that the MIs are not specific enough for them to be considered accurate.

 

[ban-all-sheds]

Never assume!

Often good advice, but I think it is reasonable for the people who write wiring regulations to assume that those reading and working to them will do so sensibly, given what they say elsewhere about people having to be skilled or instructed, and exercise reasonable skill and care etc.

I really do not accept that there can be a realistic concern about people putting lighting circuits on 1A devices 'because 559.5.1.204 doesn't specify a minimum and 1 <16 therefore it complies, so if the lights don't work that means that 559.5.1.204 is not sensible'.

 

[ban-all-sheds]

All this leads me to think that the MIs are not specific enough for them to be considered accurate.

Be that as it may...

 

[EFLImpudence]

 

[mwatsonxx]

It can be, if you assume that people reading, and working to, the regulations are sensible.

Can you confirm that all boiler manufacturers instructions are incorrect, and should be ignored.

 

[ban-all-sheds]

This appears to be the current understanding:

1. There are no requirements in the Wiring Regulations for gas appliance supplies to be fused at 3A.
2. There are no requirements in any gas regulations for gas appliance supplies to be fused at 3A.
3. The Wiring Regulations do not make it mandatory to abide by any manufacturer instructions.
4. The Gas Safety (Installation and Use) Regulations (I'm assuming it is they) do make it mandatory to abide by any manufacturer instructions.
5. Some gas appliance manufacturers require 3A fusing in the UK.
6. Some gas appliance manufacturers do not require 3A fusing outside the UK.
7. Nobody knows why #5 is justified, particularly when #6 applies to the same appliance sold elsewhere.
8. Notwithstanding #7, #4 means that observing #5 is not optional.

 

[mwatsonxx]

This appears to be the current understanding:

1. There are no requirements in the Wiring Regulations for gas appliance supplies to be fused at 3A.
2. There are no requirements in any gas regulations for gas appliance supplies to be fused at 3A.
3. The Wiring Regulations do not make it mandatory to abide by any manufacturer instructions.
4. The Gas Safety (Installation and Use) Regulations (I'm assuming it is they) do make it mandatory to abide by any manufacturer instructions.
5. Some gas appliance manufacturers require 3A fusing in the UK.
6. Some gas appliance manufacturers do not require 3A fusing outside the UK.
7. Nobody knows why #5 is justified, particularly when #6 applies to the same appliance sold elsewhere.
8. Notwithstanding #7, #4 means that observing #5 is not optional.

So what does all that mean? What is the decision of the unholy trinity? UK boiler manufacturing is at a standstill awaiting your decision.

 

[EFLImpudence]

Can you not work out anything for yourself?