Help with crimping

[JohnW2]

erm, are we writing and posting simultaneously?

Looks like it!

ermThis could get a tad complex, good job its very nearly beer o'clock

Agreed, except is nearly wine o'clock for me

Kind Regards, John

 

[mikhailfaradayski]

No, you communicate clearly, but if i were to be critical, you could try to be a little more concise

I'm certainly not known for my brevity. However, that's not because I can't be concise - it's because if I am concise, then some annoying person invariably picks me up on some detail or caveat and I could have included, but omitted in the interests of brevity!!

Yea, fair point. Sometimes dictum sapiente sat est isn't enough. Its just sometimes, dare i say it, maybe you lose the interest of the reader slightly if they haven't got all day to sit at the computer.

I agree that just asking people here will not give un-deniable proof either way, but they are permitted by the regs and presumably have undergone some testing by a collection of white coated bods in some way connected to the IET. The regs even go a little further by conditioning the crimp types that can and cannot be used on different cable types. I think it says something like 'can be used on all cable types unless marked with.......(from memory as my book is on the job at the mo, maybe someone can fill in the blanks here)

What regs are you talking about?

Our beautiful book, obviously

The real problem underlying this whole issue is that BS7671 says virtually nothing - simply a few words in one place about a joint made with a "suitable (or is it 'appropriate') compression tool". If it was a bit more specific about what was acceptable, then maybe a lot of this discussion would be unnecessary.

look further!! Seek and ye shall find.

In terms of 13 not being warm, then zero is positively chilly. Have you seen anything like air crash investigators on some Natgeo? There are teams specifically tasked with looking at reasons for catastrophic failure. So ill revise my total guess to 297.

Yes, I've seen many of those programmes, and I actually know a couple of air crash investigators, but I don't get your point.

when i (tongue in cheek) said 13. You said i wasn't warm and the answer would probably be zero. I believe this to be incorrect.

Crashes and crash investigators only come into the picture when the risk-assessment and risk-prevention measures have failed. Maybe you misunderstood or misread the question I asked

Maybe I did, or maybe your question wasn't well posed.

(to which you have given answers of 13 and 297 ) For a start, it was essentially a rhetorical question,

Ah, i missed that bit. I actually thought you were just trying to be a bit condescending (you do know what that means, don't you?)

but what it was asking (or trying to ask) is how many people have seen most of the theoretically possible failures which are considered and addressed by design and/or regulations as part of the risk-minimising design/regulation processes. The vast majority of those 'theoretical possible failures' are things which have never happened in the past (hence answer=zero) and will hopefully never happen in the future - but in many cases that is precisely because the possibility was considered and steps taken to minimise the risk of their occurring. I'm sure you really understand all this - it's at the basis of risk assessment, risk management and risk minimisation, in very many fields.
Kind Regards, John.

You've just gone off on one now haven't you

I think you have totally missed the point of my very simple question and are in danger of making crimping some bits of cable together seem like a mine field of danger and death.

8403?

 

[mikhailfaradayski]

thats it for me today, I have a date with a little Belgian beauty.

Happy hypothesizing!

 

[JohnW2]

Yea, fair point. Sometimes dictum sapiente sat est isn't enough. Its just sometimes, dare i say it, maybe you lose the interest of the reader slightly if they haven't got all day to sit at the computer.

It's a no-win situation, particularly in a forum like this. I'm sure you're right that some people are tired by long posts, but when I try to be concise, there often follows a plethora of attacks and discussion relating to the deatisl, exceptions, assumptions, qualifications etc. etc. that I decided didn't really need to be mentioned - so readers probably have to choose between being tired by lengthy posts or tired by lengthy silly point-scoring exchanges!

The real problem underlying this whole issue is that BS7671 says virtually nothing - simply a few words in one place about a joint made with a "suitable (or is it 'appropriate') compression tool". If it was a bit more specific about what was acceptable, then maybe a lot of this discussion would be unnecessary.

look further!! Seek and ye shall find.

OK, I'll do some seeking. However, I think the point is still going to remain that 526.3(iv) appears to allow a joint "made by an appropriate compression tool" to be in an inaccessible location without any qualification about details of that joint.

when i (tongue in cheek) said 13. You said i wasn't warm and the answer would probably be zero. I believe this to be incorrect.

Yes, the position of your tongue was clear enough, but what I said is that it would probably be zero 'in many cases', and I've subsequently explained that. Many of the theoretically possible failures that are considered during the design process are failures which have never previously occurred, so the number of people who have seen them will inevitably be zero in such cases.

Enjoy the beer!

Kind Regards,John

 

[JohnW2]

The regs even go a little further by conditioning the crimp types that can and cannot be used on different cable types. I think it says something like 'can be used on all cable types unless marked with ....

What regs are you talking about?

Our beautiful book, obviously

The real problem underlying this whole issue is that BS7671 says virtually nothing - simply a few words in one place about a joint made with a "suitable (or is it 'appropriate') compression tool". If it was a bit more specific about what was acceptable, then maybe a lot of this discussion would be unnecessary.

look further!! Seek and ye shall find.

OK, I've done some seeking, but have not found, and have therefore given up! It's at times like this that it would be nice if I had an electronic copy of the regs which I could search, since the index of the paper version is necessarily far from exhaustive.

Anyway, the fact is that, per what I wrote before (above), I've failed to find any specific reference to crimped joints in the regs other than the three words in 526.3(iv) relating to accessibility. If such things were in the regs, I'd exepct it to be somewhere in 526, but it's not.

Could someone please help me find the details about crimped joints which mikhailfaradayski mentioned?

Kind Regards, John.

 

[martinxxxxxx]

[ It's at times like this that it would be nice if I had an electronic copy of the regs which I could search, since the index of the paper version is necessarily far from exhaustive.

I hear a rumour that the BGB will be available as an E-Book, Hope so

 

[JohnW2]

[ It's at times like this that it would be nice if I had an electronic copy of the regs which I could search, since the index of the paper version is necessarily far from exhaustive.

I hear a rumour that the BGB will be available as an E-Book, Hope so

Probably. I'm pretty sure that the current BRB is available on CD/DVD but, apart from the ease of searching, that doesn't have the satisfaction of a real book that can get dog-eared - at least, not for me!

Kind Regards, John

 

[martinxxxxxx]

Yes the BRB is and if you buy it no from the EIT you will get free upgrade to BGB, BUT the product is bundles with other books that you may not wnat at a price of £126 (and that is if you are a IET member)

I like the dog-eared version but would like to have electronic version as well...

 

[JohnW2]

I like the dog-eared version but would like to have electronic version as well...

Oh, sure, if I could have both, at no extra cost, I certainly would!

Kind Regards, John.

 

[Paul_C]

It's worth noting that at one time the IEE Wiring Regs. did require crimped joints in general to be accessible for inspection. From the 14th edition:

B.73 Where joints in cable conductors and bare conductors are required, they shall be mechanically and electrically sound and, except in cables buried underground and special cables designed for heating, they shall be accessible for inspection. Joints in non-flexible cables shall be made either by soldering or by means of mechanical clamps or compression-type sockets which shall securely retain all the wires of the conductors. {.....}

 

[JohnW2]

It's worth noting that at one time the IEE Wiring Regs. did require crimped joints in general to be accessible for inspection. From the 14th edition:

B.73 Where joints in cable conductors and bare conductors are required, they shall be mechanically and electrically sound and, except in cables buried underground and special cables designed for heating, they shall be accessible for inspection. Joints in non-flexible cables shall be made either by soldering or by means of mechanical clamps or compression-type sockets which shall securely retain all wires of the conductors. {.....}

Thanks - that's interesting.

Does it really say "...all wires of the conductors..."? !

Kind Regards, John.

 

[martinxxxxxx]

I like the dog-eared version but would like to have electronic version as well...

Oh, sure, if I could have both, at no extra cost, I certainly would!

Kind Regards, John.

They just love money too much to actually treat us that fairly, They want the information out there but are not prepared to say once you have paid for the right to own a copy you can have it in multi formats.

I have text books on MS access that give you a cd rom of the contents.

The money that they want is is an outrage, especially as they bundle the regs with other publication and you cannot buy it as a standalone.

Martin

 

[Paul_C]

Does it really say "...all wires of the conductors..."? !

Yes. Actually it says "all the wires of the conductors," but I accidentally missed that when transcribing. I'll edit it now.....

 

[JohnW2]

Does it really say "...all wires of the conductors..."? !

Yes. Actually it says "all the wires of the conductors," but I accidentally missed that when transcribing. I'll edit it now.....

Hmmm. Any idea exactly what it's trying to say? Does it mean all the strands of a stranded conductor, or what. It's just as well the IET are not a member of this forum - such language would get them a lot of flak, I reckon!

Kind Regards, John.

 

[Paul_C]

Does it mean all the strands of a stranded conductor, or what.

That's what I would take it to mean.

I just cross-checked the same regulation in the revised 14th edition (the 1970 metric revision), and the wording had changed to allow limited inaccessibility under certain conditions:

B.73 Where joints in cable conductors and bare conductors are necessary, they shall be mechanically and electrically sound. Joints in non-flexible cables shall be accessible for inspection; provided that this requirement shall not apply to joints in cables buried underground, or joints buried or enclosed in building materials capable of satisfying the non-combustibility test of B.S.476, Part 4,* so that no danger can arise. For the purpose of this regulation, hardwood and plasterboard are deemed to be combustible, i.e. the Note to the definition of 'Non-combustible' in these Regulations does not apply. Joints in non-flexible cables shall be made by soldering, brazing, welding, or mechanical clamps, or be of the compression type; provided that mechanical clamps shall not be used for inaccessible joints buried or enclosed in the building structure. All mechanical clamps and compression-type sockets shall securely retain all the wires of the conductors. {.....}

* B.S.476 - 'Fire tests on building materials and structures, Part 4 - Non-combustibility test for materials.'