Garage RCBO tripping large machinery

[ban-all-sheds]

However, I would try not to put into the minds of DIYers the idea there are situations in which it would be acceptable to protect a 2.5mm² cable with a 32A OPD

So will you always tell people that they must not spur off a ring final with 2.5mm²?

 

[DetlefSchmitz]

In passing, I must say that I don't think I've ever met, or even heard about, a Type A MCB.

Strange - I was always lead to believe that A was avoided to prevent confusion with amps.

 

[ban-all-sheds]

What confusion might arise from thinking that a A16 breaker (for example) was a 16A device?

 

[JohnW2]

However, I would try not to put into the minds of DIYers the idea there are situations in which it would be acceptable to protect a 2.5mm² cable with a 32A OPD

So will you always tell people that they must not spur off a ring final with 2.5mm²?

You're obviously having a quiet, hence pedantic, day.

Yes, I probably would tell them that if the 32A OPD were the only thing protecting the cable - i.e. they planned to connect the spur cable to something that did not implicitly include overcurrent protection (or was incapable of creating an overload) - which, of course, is not going to happen (and now you're probably going to wheel out a 20A/26A argument).

Kind Regards, John

 

[JohnW2]

Just like the plumbers then - patronisingly witholding the truth because it's easier for you than explaining things properly.

You really are being awkward for the sake of it. Particularly when one knows nothing about the knowledge and/or intelligence of people who may read ones words, it's often far better to give simple, easily understood, 'erring on the side of safety' advice than to give more complex explanations about 'exceptions' that some readers could well not fully understand.

Kind Regards, John

 

[ban-all-sheds]

You're obviously having a quiet, hence pedantic, day.

No - I'm having a day where I am keen on truth and accuracy.

Yes, I would tell them that if the 32A OPD were the only thing protecting the cable

Against what?

i.e. they planned to connect the spur cable to something that did not implicitly include overcurrent protection - which, of course, is not going to happen

It isn't going to happen, as I was talking about a spur from a 32A ring final. Pedantic it would indeed be to have explicitly stated that I meant a ring final supplying BS 1363 accessories, and that the spur would also be fused, or supplying a socket outlet.

(and now you're probably going to wheel out a 20A/26A argument).

No, but I am going to ask you to explain the conflict between

"I would try not to put into the minds of DIYers the idea there are situations in which it would be acceptable to protect a 2.5mm² cable with a 32A OPD, even if there are some situations in which those with expert knowledge and the ability to confirm that fault protection was adequate"

and this, for example:

With a standard 2.5mm² ring circuit, the 2.5mm² cable of a spur is adequate to supply one socket

 

[ban-all-sheds]

You really are being awkward for the sake of it.

No - I am fighting against the terrible idea that one should not tell people the truth because you don't think they could understand it and and you can't be bothered to explain it to them.

Particularly when one knows nothing about the knowledge and/or intelligence of people who may read ones words, it's often far better to give simple, easily understood, 'erring on the side of safety' advice than to give more complex explanations about 'exceptions' that some readers could well not fully understand.

No no no no no no no.

It is never, ever acceptable to tell people that they may not do ABC when they may. If they do not properly understand what they are doing and still go ahead that is 100% their responsibility, 0% yours, and a patronising belief that they must only be told things which even the simplest can understand is reprehensible, and totally unacceptable when it compromises the advice you give.

 

[JohnW2]

It is never, ever acceptable to tell people that they may not do ABC when they may. If they do not properly understand what they are doing and still go ahead that is 100% their responsibility, 0% yours

I disagree.

Kind Regards, John

 

[DetlefSchmitz]

What confusion might arise from thinking that a A16 breaker (for example) was a 16A device?

Not sure if you're being sarcastic just to me or the world in general, but it is a fact that EN 60898 only defines types B C and D, replacing the earlier 1 2 and 3 types. The internet meme thinks that 'A' was avoided for the reason I stated. I assume you have better information?

 

[JohnW2]

...but it is a fact that EN 60898 only defines types B C and D, replacing the earlier 1 2 and 3 types.

Are you sure about that? The page of the Siemens document to which EFLI linked was headed "Tripping characteristics acc. to EN 60 898", and includes Type A (which, as I said, was a new one on me) as well as Types B, C & D. Have Siemens 'invented' the data for the Type A?

Kind Regards, John

 

[DetlefSchmitz]

...but it is a fact that EN 60898 only defines types B C and D, replacing the earlier 1 2 and 3 types.

Are you sure about that? The page of the Siemens document to which EFLI linked was headed "Tripping characteristics acc. to EN 60 898", and includes Type A (which, as I said, was a new one on me) as well as Types B, C & D. Have Siemens 'invented' the data for the Type A?

Kind Regards, John

I just checked the BS EN 60898-2-2006 addition to be sure - still no mention of type A. So unless there is a later version - I guess they did.

 

[JohnW2]

Are you sure about that? The page of the Siemens document to which EFLI linked was headed "Tripping characteristics acc. to EN 60 898", and includes Type A (which, as I said, was a new one on me) as well as Types B, C & D. Have Siemens 'invented' the data for the Type A?

I just checked the BS EN 60898-2-2006 addition to be sure - still no mention of type A. So unless there is a later version - I guess they did.

Very odd. One might even suspect from the fact that Type A is included in the Seimens document that they actually make them!

Kind Regards, John

 

[EFLImpudence]

Very odd. One might even suspect from the fact that Type A is included in the Seimens document that they actually make them!

It would seem Google has not heard of type A either.

Have they, for whatever reason, been changed to type Z?
Go to 5 - https://en.wikipedia.org/wiki/Circuit_breaker

 

[JohnW2]

Very odd. One might even suspect from the fact that Type A is included in the Seimens document that they actually make them!

It would seem Google has not heard of type A either.

I get 2370 hits for "Type A MCB". Most of the hits which relate to actual products seem to relate to Siemens products (in many cases 'clearance' or 'discontinued'), so it does seem that it may have been an invention of theirs. As an illustration, here is one example

Kind Regards, John

 

[EFLImpudence]

I get 2370 hits for "Type A MCB".

That's strange. I get 6,790,000 hits, none of which relates to Type A MCBs - well, not the first page.