Wiki entry on Junction Boxes

[JohnW2]

Forgive my ignorance, but where does BS 7671 require that screw-terminal JBs must be accessible? 526.3 demands that all connections be accessible, except [etc, etc]. It does not exempt screwless JBs.

Sure, it does not specifically require screw-terminal JBs to be accessible. rather, it requires all connections to be accesible unless they fall into one of the five exempt categories given in 526.3. ....

It does exempt "A joint forming part of the equipment complying with the appropriate product standard, which if we accept that a JB is 'electrical equipment' could be screw, screwless, friction or something else, as long as there is a product standard for it and the MIs don't preclude it.

... and that is, indeed, the fifth of those exemptions. Someone else brought this up earlier in the thread, and it's the very reason we've been showing this interest in what the British Standards actually have to say. We have, as far as I can see, so far identified no "appropriate product standard" that would apply to screwless connections.

Furthermore, and I think probably more importantly, some people seem to be interpreting 526.3(v) very differently from me. To me, a "joint forming part of the equipment" refers to a joint which is a manufactured part of a piece of (relevant Standard-compliant) equipment (e.g. joints within an MCB or RCD), rather than a joint made by an electrician using 'a piece of equipment' (such as a JB). However, I'm sure there is scope for debate here!

Kind Regards, John.

 

[stillp]

[quote="JohnW2";p="2036126We have, as far as I can see, so far identified no "appropriate product standard" that would apply to screwless connections.
[/quote]
On the contrary, we have identified several, but they apply equally to screwless and screwed (and other) connecting units.

Yor second point is interesting. You could be right, but I suspect the relevant IEC Working Group couldn't agree on that and so committed the cardinal sin of leaving the wording ambiguous. Does a joint made by a JB constitute "part of the equipment"? I would say yes...

 

[JohnW2]

We have, as far as I can see, so far identified no "appropriate product standard" that would apply to screwless connections.

On the contrary, we have identified several, but they apply equally to screwless and screwed (and other) connecting units.

OK, although I thought my meaning would be clear, to be absolutely precise I guess I should have written '....so far identified no specific "appropriate product standard" for screwless connections...'. As you've said, the Standards so far examined have not really distinguished between different types of connections - so if they were being taken to exempt the Ashley/Hager type of connections from the need to be accessible, per 526.3(v), then the same argument could apply to any type of junction box (including those with screwed connections) - and I really don't think that anyone seriously believes that the IET intended to be allowing use of, say, (BS EN 60670-22-compliant) screw-connection JBs in inaccessible locations,do you?

Yor second point is interesting. You could be right, but I suspect the relevant IEC Working Group couldn't agree on that and so committed the cardinal sin of leaving the wording ambiguous. Does a joint made by a JB constitute "part of the equipment"? I would say yes...

Well, maybe this is also a cardinal sin (in relation to the product of a committee!). but my reason for being more inclined to my view (i.e. a 'No' answer) is that the alternative would make little sense to me. Just as above, per the view you're taking, it would seem that any sort of connection in any sort of JB would be allowed in an accessible place, provided only that the connection was made using 'a piece of equipment' (e.g. a screw-terminal JB) which was compliant with "an appropriate product standard". Again, I find it seriously hard to believe that such was the IET's intent - because it would, in practice, effectively almost anihilate the restriction on inaccessible connections in above-ground wiring. Am I wrong?

Kind Regards, John.

 

[stillp]

I really don't think that anyone seriously believes that the IET intended to be allowing use of, say, (BS EN 60670-22-compliant) screw-connection JBs in inaccessible locations,do you?

I have no idea what they (actually JPEL/64, rather than the IET) intended.
However my earlier question about the possible meanings of "maintenance free" was intended to explore whether they allowed the use of say crimps in inaccessible locations because they don't need maintenance, or because they can't be maintained anyway so there's no point in them being accessible.

 

[JohnW2]

However my earlier question about the possible meanings of "maintenance free" was intended to explore whether they allowed the use of say crimps in inaccessible locations because they don't need maintenance, or because they can't be maintained anyway so there's no point in them being accessible.

I understood that but, as I said in my response, if there is any sanity in the situation (which some people may say is not inevitable in relation to the work of a committee), they would surely not allow something to be inaccessible (whether or not it was something that could be maintained) if they didn't believe that it would remain OK/safe without maintenance, would they? In other words, to allow it to be inaccessible, one would hope that they would have satisfied themselves that, say, a crimped joint not only couldn't be maintained but did not need to be 'maintained', either.

Kind Regards, John.

 

[JohnW2]

I really don't think that anyone seriously believes that the IET intended to be allowing use of, say, (BS EN 60670-22-compliant) screw-connection JBs in inaccessible locations,do you?

I have no idea what they (actually JPEL/64, rather than the IET) intended.

Even if you have no idea, there seems to be an almost universal belief that their intention was to not allow JBs with screwed connections to be installed in inacessible locations. Of course, everyone may be wrong in that belief.

Kind Regards, John.

 

[stillp]

Well, there are many people who would say that a properly designed and installed screw type connection box does not need maintenance. Some might even say that such connections in a domestic installation should be made inaccessible to prevent them being b*****ed about with.
Is there anything in BS 7671 that is more specific than 526.3?

 

[JohnW2]

Well, there are many people who would say that a properly designed and installed screw type connection box does not need maintenance.

For what little my opinion may be worth, I think I probably number myself amongst such people. As I've often said (before rapidly retiring to avoid the flak!), I am far happier to have inaccessible screw-terminal JBs in my house (which I do) than I would be to have any inaccessible crimped joints.

Some might even say that such connections in a domestic installation should be made inaccessible to prevent them being b*****ed about with.

They might, but that would be a little silly. If one is going to allow anything (other than cable) to be inaccessible in an electrical installation, it should be on the basis of it being considered pefectly safe so to do - not because of considerations of possible abuse. Let's face it, one cannot make CUs and accessories inaccesible to potential perpetrators of 'b*****ing about'!

Is there anything in BS 7671 that is more specific than 526.3?

Very little, and that's the problem. Were it not for 526.3(v) (which, as I've said, seems to mean something different to me than it does to some others), I doubt that anyone would be suggesting that 526.3 allowed the Ashely/Hager box to be used in an inaccessible location. However, as recently brought to our attention, in relation to ring and radial final 'socket' circuits the ('informative') Appendix 15 does seem to imply that it may be permissible to have JBs with 'maintenance-free connections' in inaccessible places, but such connections are not defined there, nor (as far as I can see) even mentioned anywhere else in BS7671.

Kind Regards, John.

 

[mikhailfaradayski]

Has anyone commenting on this actually used/closely examined one of the ashley type boxes in question?

If so, what do you think to the quality of the connection?

Have you seen one fail?

Is it beyond the realms of possibility that the 'appropriate compression tool' mentioned in the regs is actually an integral part of said boxes?

Do you think the insurers/solicitors acting for the manufacturer would have asked them what assurances they could give to substantiate their claim before advising them that it was a sound claim to make? Could this involve some account of their testing regime?

 

[mikhailfaradayski]

.......It's almost a daily occurrence that someone on this forum is reminded of the need for JBs to be accessible, and I cannot recall even once having seen it suggested that use of these 'maintainance-free' products would be a possible solution.

Kind Regards, John.

Hi John,

But advice of this nature has been given on this forum in the past.

No connections at all is always preferred (as I'm sure you realize) but we all know that they will continue to appear until such time that installation of a JB becomes an offence punishable by castration

 

[JohnW2]

Has anyone commenting on this actually used/closely examined one of the ashley type boxes in question?

Closely examined, yes, several. Used (in a real installation), no - only for experiments.

If so, what do you think to the quality of the connection?

Seeming very well manufactured, and 'nice'. At least in short-term, quality of connection seems fine (more consistently secure, and more difficult to pull apart, than crimped joints made by my hands). Didn't heat significantly with considerable over-current through them during experiments.

Have you seen one fail?

Not really applicable, in my case. To be fair, I haven't seen a screw-terminal JB 'fail', either - although I imagine that's probably a function of my limited exposure.

Is it beyond the realms of possibility that the 'appropriate compression tool' mentioned in the regs is actually an integral part of said boxes?

Not really possible, since it's not a compression joint - it's a spring one., which isn't really the same thing.

Do you think the insurers/solicitors acting for the manufacturer would have asked them what assurances they could give to substantiate their claim before advising them that it was a sound claim to make? Could this involve some account of their testing regime?

Their promotional material is worded extremely cleverly, and gets within a tiny hair's breath of claiming that their use in inaccessible places is BS7671-compliant without actually saying so - not the least in the title of their 'Junction Box Guide to 17th edition".

I suspect that it's a very good product. It's a reputable company, and I have no doubt that there tests have established that the product is very reliable. However, in the absence of any specific regulations/standards, neither they nor anyone else can really say whether or not the product is sufficiently more relaiable than screw-terminal connections to make it reasonable for it to be used in inaccessible locations. That is an arbitrary line in the sand drawn by BS7671, so really only BS7671 can decide where that line is to be drawn. Hence no third parties can really make any claims about such compliance.

If and when I see an electrician on this forum actually suggest/advise that a poster should use a product of this type in an accessible location, I might start believing that my doubts about it's compliance with BS7671 are not as widespread as I suspect they are. I very much doubt that most electricians will feel comfortable about using these products in inaccessible locations unless/until BS7671 makes it much more clear that they probably are.

Kind Regards, John

 

[JohnW2]

.......It's almost a daily occurrence that someone on this forum is reminded of the need for JBs to be accessible, and I cannot recall even once having seen it suggested that use of these 'maintainance-free' products would be a possible solution.

But advice of this nature has been given on this forum in the past.

I have to take your word for that (it would be interesting if you could cite some examples). All I can say is that I have not seen such advice being given in the 6 months or whatever that I've been around here (nor in other forums I've monitored). Posters very often get reminded that traditional JBs in inaccessible locations are not allowed. Occasionally crimping is suggested as an alternative which can be used in an inaccessible location, but I've yet to see a poster being advised to use a 'maintenance-free JB' of the type we're discussing.

Kind Regards, John.

 

[mikhailfaradayski]

.......It's almost a daily occurrence that someone on this forum is reminded of the need for JBs to be accessible, and I cannot recall even once having seen it suggested that use of these 'maintainance-free' products would be a possible solution.

But advice of this nature has been given on this forum in the past.

I have to take your word for that (it would be interesting if you could cite some examples)

sorry, that would involve searching for likely text strings, which i'm sure you are perfectly capable of, should you desire to do so.

. All I can say is that I have not seen such advice being given in the 6 months or whatever that I've been around here (nor in other forums I've monitored)

I do recall discussion about them in the 2 or 3 years i have been lurking around

Posters very often get reminded that traditional JBs in inaccessible locations are not allowed.

as they should

Occasionally crimping is suggested as an alternative which can be used in an inaccessible location, but I've yet to see a poster being advised to use a 'maintenance-free JB' of the type we're discussing.

ref above

Kind Regards, John.

 

[JohnW2]

. All I can say is that I have not seen such advice being given in the 6 months or whatever that I've been around here (nor in other forums I've monitored)

I do recall discussion about them in the 2 or 3 years i have been lurking around

Oh, even in the few months I've been around, I've seen previous discussions about them. What I haven't seen (and frankly doubt has ever happened - so I'm not terribly motivated to look back before 'my time'!) is a poster being given advice (or even suggestion) that they should use one of these things in an inaccessible place.

Kind Regards, John.

 

[mikhailfaradayski]

Has anyone commenting on this actually used/closely examined one of the ashley type boxes in question?

Closely examined, yes, several. Used (in a real installation), no - only for experiments.

If so, what do you think to the quality of the connection?

Seeming very well manufactured, and 'nice'. At least in short-term, quality of connection seems fine (more consistently secure, and more difficult to pull apart, than crimped joints made by my hands). Didn't heat significantly with considerable over-current through them during experiments.

I agree, they seem very secure and give a sound connection.

When you tried to pull the termination apart, did you have the strain relief correctly fitted? When fully fitted, i imagine the joint is near impossible to pull apart by hand

Have you seen one fail?

Not really applicable, in my case. To be fair, I haven't seen a screw-terminal JB 'fail', either - although I imagine that's probably a function of my limited exposure.

fair enough. Somewhat similar to your position on exposure to crimping

Is it beyond the realms of possibility that the 'appropriate compression tool' mentioned in the regs is actually an integral part of said boxes?

Not really possible, since it's not a compression joint - it's a spring one., which isn't really the same thing.

Are you suggesting that these terminals are not exerting some kind of compressive force upon the conductor and that that force is not appropriate for the task? It looks like they are.

Do you think the insurers/solicitors acting for the manufacturer would have asked them what assurances they could give to substantiate their claim before advising them that it was a sound claim to make? Could this involve some account of their testing regime?

Their promotional material is worded extremely cleverly, and gets within a tiny hair's breath of claiming that their use in inaccessible places is BS7671-compliant without actually saying so - not the least in the title of their 'Junction Box Guide to 17th edition".

I dont really wish to go down this well-trodden, never ending path on who complies with who. Its far too tedious to bother with, sorry.

I suspect that it's a very good product. It's a reputable company, and I have no doubt that there tests have established that the product is very reliable. However, in the absence of any specific regulations/standards, neither they nor anyone else can really say whether or not the product is sufficiently more relaiable than screw-terminal connections to make it reasonable for it to be used in inaccessible locations. That is an arbitrary line in the sand drawn by BS7671, so really only BS7671 can decide where that line is to be drawn. Hence no third parties can really make any claims about such compliance.

see last comment.

If and when I see an electrician on this forum actually suggest/advise that a poster should use a product of this type in an accessible location, I might start believing that my doubts about it's compliance with BS7671 are not as widespread as I suspect they are. I very much doubt that most electricians will feel comfortable about using these products in inaccessible locations unless/until BS7671 makes it much more clear that they probably are.

Kind Regards, John