Maintenance-free JBs

[JohnW2]

OK,the BGB seems to have clarified the situation:

1... 526.3(v) has now been re-worded, such as to confirm the view I previously expressed that it was referring to joints made by a manufacturer within items of equipment - and therefore clearly does not relate to joints in JBs made by electricians (or whoever).

2... 526(vi) has been added, allowing the use of maintenance-free JBs in inaccessible locations, provided that they are compliant with BS5733 and bear the symbol "MF" within a circle.

I think it's probably fair to say that, on that basis, the Ashley J803 and J804 JBs, in their present form, do not comply with 526.3(vi). Whether or not they comply with BS5733, there are no claims or markings to indicate such compliance, and they obviously do not bear the 'MF' symbol.

One assumes that Ashley will be addressing these issues and therefore will fairly soon (if not already) be selling products which do comply with 526(vi) (I'm expecting a small delivery today, just to make sure that they have not been changed already) - but I'm not sure that makes use of the current products in inaccessible locations compliant, does it?

Kind Regards, John.
Edit: typo corrected.

 

[Paul_C]

No doubt that the manufacturers will be quick to seize upon the revision and get the "MF" mark added to all their qualifying joint boxes.

Personally, and as discussed in the crimp thread recently, I still wouldn't install them in inaccessible locations. Whether screw-terminal, crimps, or these so-called "maintenance free" connections, I want them reasonably accessible.

 

[JohnW2]

No doubt that the manufacturers will be quick to seize upon the revision and get the "MF" mark added to all their qualifying joint boxes.

Indeed. They might even have done so already. However, goodness knows how much 'old stock' will be around.

Personally, and as discussed in the crimp thread recently, I still wouldn't install them in inaccessible locations. Whether screw-terminal, crimps, or these so-called "maintenance free" connections, I want them reasonably accessible.

As you know, I totally agree. In an ideal world, I wouldn't want any inaccessible joints in my house - and if I have to have some, would only be totally happy if they were soldered or brazed (and protected from mechanical stresses). Primarily because of the high degree of 'installer-dependence', I will remain out on my limb in saying that crimped joints are at the bottom of the list of those I'd want to be inaccessible! I suppose that means, in practice, that if I had to have inaccessible joints other than soldered ones, I'd probably now favour these 'maintenance-free' jobbies.

Kind Regards, John.

 

[holmslaw]

..

 

[JohnW2]

Some bizarre logic going on here, a soldered or brazed joint is totally dependent on the installers skill, and there is no practical way of proving the mechanical and electrical properties of the joint. Alternatively, a crimped joint comprises a correctly sized crimp, matched to the cable and crimped by using a correctly sized crimping tool that only releases once the crimp has been correctly compressed.

I can understand some people feeling that my logic is inconsistent, but that's how it is. In honesty, I'd probably only be totally comfortable with a soldered/brazed joint if I'd made it myself, which is also probably illogical. However, I feel that that anyone with some experience of soldering/brazing would probably know, by inspection, whether or not the joint they had just made was OK or not. For better or worse, I remain uncomfortable about the whole idea of crimping solid conductors, no matter who makes the joint and with what tool.

Kind Regards, John.

 

[Chapster]

I know where you're coming from. What I did to make myself feel better since it was in my own home several months ago, is crimp the solid conductors using uninsulated crimps, then flow solder into the barrels of the crimps. Then a few layers of heatshrink over each barrel as well as spacing them slightly apart and heatshrinking the whole lot. Decided mechanical pressure and solder retention to increase mechanical strength and decrease joint resistance couldn't be a bad thing.

At work, we just use the crimps and proper crimping tools. Although I must say, that because I didn't trust crimps overly, I decided to do a test. I crimped some solid core t+e cores with loop-type crimps, screwed through the loops into the bench to hold them steady and then grabbed the wire and leant back. Throwing caution to the wind, I put my full body weight on the wire by the end, and the crimp held. Must say I was impressed and surprised. Dunno what the story would've been if I got the 18-stone meathead to do the same test on it, but still proved just how much strain it could take without releasing.

 

[JohnW2]

I know where you're coming from. What I did to make myself feel better since it was in my own home several months ago, is crimp the solid conductors using uninsulated crimps, then flow solder into the barrels of the crimps. ..... Decided mechanical pressure and solder retention to increase mechanical strength and decrease joint resistance couldn't be a bad thing.

Obviously a man after my own heart, no matter how illogical or paranoid I (and maybe you ) may be. I must say that I have contemplated doing precisely what you describe, although I never have actually done it.

At work, we just use the crimps and proper crimping tools. Although I must say, that because I didn't trust crimps overly, I decided to do a test. I crimped some solid core t+e cores with loop-type crimps, screwed through the loops into the bench to hold them steady and then grabbed the wire and leant back. Throwing caution to the wind, I put my full body weight on the wire by the end, and the crimp held. Must say I was impressed and surprised. Dunno what the story would've been if I got the 18-stone meathead to do the same test on it, but still proved just how much strain it could take without releasing.

I wonder what you mean by 'proper crimping tools' - do you mean a concentric (e.g. hex) crimper, rather than the 'single-plane squasher', as I usually call it, which most electricians seem to use? Using such a tool, my experiences (all in 'bench testing') have been a little different from yours. I've done many test crimps such as you describe, and most of the time, the result was exactly as you report. However, occasionally (maybe in around 5% of cases), when I pulled the conductor came flying out with relatively little force applied - thereby doing nothing to reassure me!

Kind Regards, John.

 

[scousespark]

I know where you're coming from. What I did to make myself feel better since it was in my own home several months ago, is crimp the solid conductors using uninsulated crimps, then flow solder into the barrels of the crimps. ..... Decided mechanical pressure and solder retention to increase mechanical strength and decrease joint resistance couldn't be a bad thing.

Obviously a man after my own heart, no matter how illogical or paranoid I (and maybe you ) may be. I must say that I have contemplated doing precisely what you describe, although I never have actually done it.

At work, we just use the crimps and proper crimping tools. Although I must say, that because I didn't trust crimps overly, I decided to do a test. I crimped some solid core t+e cores with loop-type crimps, screwed through the loops into the bench to hold them steady and then grabbed the wire and leant back. Throwing caution to the wind, I put my full body weight on the wire by the end, and the crimp held. Must say I was impressed and surprised. Dunno what the story would've been if I got the 18-stone meathead to do the same test on it, but still proved just how much strain it could take without releasing.

I wonder what you mean by 'proper crimping tools' - do you mean a concentric (e.g. hex) crimper, rather than the 'single-plane squasher', as I usually call it, which most electricians seem to use? Using such a tool, my experiences (all in 'bench testing') have been a little different from yours. I've done many test crimps such as you describe, and most of the time, the result was exactly as you report. However, occasionally (maybe in around 5% of cases), when I pulled the conductor came flying out with relatively little force applied - thereby doing nothing to reassure me!

Kind Regards, John.

wow 7 pages because somebody used the term plug top and 3 separate topics about ashleys. FWIW I am an electrician.

If I'm installing new, I don't have to worry about JBS.

If I'm extending and it's accessible I'm happy with a standard JB, although I do like the simplicity of ashleys. I've even been known to use wagos or connector strips. Reading this, it seems like most sparks, I use whatever is available. That's why it all exists.

I have never rewired on a bench, nor asked a couple of 20 stone blokes to try and pull a joint apart.

 

[Chapster]

Obviously a man after my own heart, no matter how illogical or paranoid I (and maybe you ) may be. I must say that I have contemplated doing precisely what you describe, although I never have actually done it.

I've had crimps fail and have come across crimps made by others that have failed. As it was in my own home, I didn't like the idea of an inaccessible joint (it was to become) relying solely on crimps, just in case my crimps turned out to be unreliable because sometimes it's the person doing the crimping's fault, and sometimes it just seems random when one doesn't do the job adequately. I'd rather solder them at work but time and a boss who wants everything done 5 minutes ago means I'm not permitted such excesses when regulations do allow crimping in such circumstances.

I wonder what you mean by 'proper crimping tools' - do you mean a concentric (e.g. hex) crimper, rather than the 'single-plane squasher', as I usually call it, which most electricians seem to use?

I suppose 'proper' when used with most things is a little subjective at best... I too was thinking of the single-plane squasher type, and used 'proper' to refer to the other type you mention, which is the tool we use. Despite successful testing at work that single time, I have come across crimps that have just pulled off despite looking as though they'd been crimped properly. The contractors who installed hundreds of outlet boxes all over the grounds used bootlace ferrules on the bunched-together split-concentric neutrals. We've had a few where the neutrals pull out easily. Others that have slowly worked their way out, which we find when turning up to discover the cause of flickering power, often finding the subsequent arcing has melted and blackened the connection blocks in the box. Altogether, it's caused me to question their efficacy because that 5% of cases where they fail may bite you on the backside.

 

[Chapster]

I have never rewired on a bench, nor asked a couple of 20 stone blokes to try and pull a joint apart.

Do I smell sarcasm or it is just my nose playing up?

I didn't rewire on a bench. I wanted to test just how effective crimps are, and if you read my message properly, you'll see that. I gather you speed-read and missed the context. Had bootlace ferrules coming off neutrals over the years (qualified contractors' workmanship there) which melted part of a distribution box in a worst case. Failure of component or the person who did the crimp? I wanted to test and see just how well crimps held up in general.

Dunno where you got two 20 stone blokes from. I only know one 18 stone bloke at work, like I said, and it was in jest when I said I didn't know what would have happened if he'd pulled on the wire. Bench probably would have gone with him. Nor did I get him to pull that, or any other, joint apart. Speed-reading isn't working amigo.

 

[JohnW2]

Do I smell sarcasm or it is just my nose playing up?

I think your nose is fine but, on the basis of the rest of what was written, I think you can sleep soundly in the knowledge that most of the sarcasm (apart from the sentence you quoted) was directed at me

Kind Regards, John.

 

[JohnW2]

wow 7 pages because somebody used the term plug top and 3 separate topics about ashleys.

You missed the ones about crimping

If I'm extending and it's accessible I'm happy with a standard JB, although I do like the simplicity of ashleys. I've even been known to use wagos or connector strips. Reading this, it seems like most sparks, I use whatever is available. That's why it all exists.

Indeed, and I agree with all that. Most of the discussions to which you refer relate to inaccessible locations. What would you do in that siuation?

Kind Regards, John.

 

[JohnW2]

I've had crimps fail and have come across crimps made by others that have failed. As it was in my own home, I didn't like the idea of an inaccessible joint (it was to become) relying solely on crimps, just in case my crimps turned out to be unreliable because sometimes it's the person doing the crimping's fault, and sometimes it just seems random when one doesn't do the job adequately.

Indeed. Hence my not being 'comfortable' about inaccessible crimps of solid conductors.

I suppose 'proper' when used with most things is a little subjective at best... I too was thinking of the single-plane squasher type, and used 'proper' to refer to the other type you mention, which is the tool we use.

I'd certainly be much happier if a 'proper' tool weres used, but the impression I get is that they don't (often or at all) get used in domestical electrical installations.

.... I have come across crimps that have just pulled off despite looking as though they'd been crimped properly. The contractors who installed hundreds of outlet boxes all over the grounds used bootlace ferrules on the bunched-together split-concentric neutrals. We've had a few where the neutrals pull out easily. Others that have slowly worked their way out, which we find when turning up to discover the cause of flickering power, often finding the subsequent arcing has melted and blackened the connection blocks in the box. Altogether, it's caused me to question their efficacy because that 5% of cases where they fail may bite you on the backside.

Thank you very much for that insight. It re-inforces my concerns and it's nice to find someone who has actually experienced the problems - I usually get ridiculed for daring to mention the possibility of 'failed crimps' because I mention the possibility without having the experience to have seen any such failures.

Kind Regards, John.

 

[scousespark]

I was being a bit sarcastic, but I think you are worrying over a small problem.

If a joint is made properly, it won't fail. This joint may be made using any of the techniques and equipment avialable to us.

In reality, a joint is a fudge as it is never as reliable as a full length of cable from point to point.

 

[Chapster]

You may well be right, and it is only a small problem, but I didn't say I was worrying over it. A 5 minute test between jobs in the workshop isn't quite the same as me losing sleep over it. In my own home, however, I opted for solder as well. That's my option and preference, and I don't think ridicule or sarcasm is a fair response.

The bootlace ferrules I referred to were crimped as absolutely as the tool permits, if comparison to other, still very secure, crimps was anything to go by. Why it failed is something I don't know. Maybe some cores are harder than others and the copper doesn't compress to leave a dent in which the crimp material can 'sit' in and remain lodged, perhaps there's space to the sides inside the crimp's barrel when the top is compressed and the cores then move to the side slightly afterwards and loosen... I have no definite answer.

I can remark, though, that the split concentric's neutrals in these installations are very hard and difficult to bend (for their given CSA) and didn't show much indentation from the crimping procedure, despite the ferrule itself being deeply dented as expected.

I do agree that in the main they are effective and hold tight. There are roughly 1000 of these supply boxes, and numerous distribution panels feeding them, and I've only come across several with loose crimps. The senior electrician, if doing any routine work inside the boxes, cuts off the bootlace ferrule on the neutrals as a matter of course and inserts the neutrals directly into the connector block for this very reason, as he's come across far more instances than I have (he's worked there many years longer than me). As I said in an earlier post, maybe the person doing the crimping is the trouble - human error. Interestingly, I've come across far more terminal screws that have been missed during tightening in supply boxes, distribution panels, CUs, light switches and sockets so human error is much more of a concern!