inaccessible Junction Boxes

[JohnW2]

The question is can a manufacturer self-certify, or does it have to be done by an authorised testing house?

Indeed so - although I probably should ask "authorised by whom", given that Standards are Standards, not regulations. ... and, needless to say, I don't know the answer to the question.

Even if samples of a product were initially 'type tested' by some third party, ongoing testing during manufacturing to confirm ongoing conformity with the relevant Standard(s) would presumably still be undertaken by the manufacturer.

Kind Regards, John

 

[JohnW2]

Another point. You mentioned it was similar to grouping of cables causing a derating of their ccc. Another way to overcome this is to increase the csa of the cable. 804s do not afford this option and merely state a 20A limit - even if the 20A were on 4mm² conductors.

Indeed.

We are doing an awful lot of speculating. As I've just written, I find it hard to believe that the heat generated by a few very short lengths of conductor is really the issue, so this line of discussion might well be a complete red herring. It really started with the observation that Wago seem to think that down-rating of the connectors (again to 20A, so perhaps not a co-incidence??) and limiting the total )'aggregate' current in all conductors in a Wagobox is necessary for MF use of Wagos

As I've said numerous times, we need to discover what BS 5733 says. Is it, for example, perhaps possible that for some (possibly arbitrary!) reason it restricts 4-terminal (or ≥4-terminal) MF JBs to 20A? - if so, that could explain the down-rating of Wagos to 20A for MF use in a Wagobox

Kind Regards, John

 

[EFLImpudence]

Sure, but that's entirely because the 1.5mm² cable is running at 100% of its CCC (Table 4D5, not 4D2A!), but the 4mm² cable only at about 86% of its CCC. If you could find a cable whose CCC was exactly 32A, it would presumably reach the same temp as the 1.5mm² one (assumed 70 in both cases). However, I'm not sure of your point here.

Yes, I know that otherwise I wouldn't be able to give it as an example.
My point is just that. The 20A limit is not the only factor if temperature is the consideration.

As you say, I previously commented that if the connectors had such high a contact resistance that they got significantly hot (at rated current), then they would probably not be fit for purpose. However, I suppose it's possible that the manufacturers believe that, whilst OK up to 'rated' current, they might get hot if one exceeded the current rating they specify. However, as you have observed, that could not explain the difference in ratings between J803s and J804s, assuming that we are right in assuming that the connectors in both are identical (they certainly look identical).

They are identical - just an extra one.
What would be the point of making a smaller one?

Maybe. I'm having difficulty in focussing my mind on this issue, since I struggle to think of practical situations in which one would want a '4-terminal' JB other than on a lighting or similar circuit, in which all currents would usually be low, much lower than even 20A. I just wonder whether the manufacturer's might have thought similarly, and specified an arbitrary 20A rating since they did not envisage anyone wanting to use it for higher currents than that - about the only advantage to them being that they would then only have to test it to 20A or thereabouts.

Yes, I have only ever used them for lights - probably why I've never thought about it before.
Is the 804 just an MF replacement for the 501?

I must say that I do find it hard to see how the heat generated by an inch or three of each of two, three or four cables is going to make any difference to anything, even if one could contrive for them all to be simultaneously carrying 100% of their CCC. That again makes me wonder whether there actually is any particularly logical reason for the difference in current ratings of the J803 and J804 (assuming the connectors really are identical).

There is, of course, the point that we don't really need a 32A one.
Joint in cooker circuit?

Is it perhaps a concession to The UK?
They made a 20A one for Hagerland (It must have come first as it has room for four) then took out one and judged it good enough for 32A.

Can one use an 804 for 32A if you leave one empty? Whyever not?

 

[JohnW2]

I have had a reply.

... and, as you can imagine, I am surprised by it. However, I think it yet again illustrates the fact that we really need to know a bit about what BS 5733 actually says!

(2)Yes. The MF mark is on the underside of the Lid. BS 5733 requires the MF mark to be visible during installation.

Hmmm. There are umpteen photos on eBay of Wagoboxes with their lids open, and, having tried quite hard, I cannot seen an 'MF' mark on any of them. Has anyone seen such an animal which does have this marking?

.... The MF mark was introduced in BS 5733. For an accessory to have the MF mark the connectors and enclosure together must pass a number of tests specified in BS 5733.

Again, we need to know about these requirements and tests.

As an aside, can I ask you to consider desisting from using numbered lists in your posts. For the second time in the last 24 hours, I have had to jump through all sorts of hoops to quote from such a post of yours! Thanks.

Kind Regards, John

 

[JohnW2]

They are identical - just an extra one.

Are we certain about that? J803s and J804s are exactly the same price from TLC. Given that the cost of the casing is presumably trivial, one might have expected the J804 to be almost 33% more expensive. Are we certain that they don't make a 'cheaper' one for the J804?

What would be the point of making a smaller one?

If they assume that people will only use them for low-current (e.g. lighting) applications, one 'only capable' of 20A would be more than adequate, so if they could make a cheaper 'inferior' one, it would facilitate selling it for the same price as a J803.

Yes, I have only ever used them for lights - probably why I've never thought about it before.

Same here, on both counts.

There is, of course, the point that we don't really need a 32A one. Joint in cooker circuit?

Are you suggesting that a 20A would be adequate for a join in (or spur from) a ring final, given that the cable CCC only has to be 20A? I think that suggestion might raise some eyebrows! Anyway, a joint or branch in a 32A radial would presumably need one.

Can one use an 804 for 32A if you leave one empty? Whyever not?

If your speculation about this all being about cable-generated heat were correct then, electrically, I suppose one could - but it would not be in accordance with the MIs!

Kind Regards, John

 

[EFLImpudence]

Are you suggesting that a 20A would be adequate for a join in (or spur from) a ring final, given that the cable CCC only has to be 20A? I think that suggestion might raise some eyebrows!

I thought that was a given.
Although one block would be empty.

Anyway, a joint or branch in a 32A radial would presumably need one.

Oh, of course. Silly me. Can't think of everything at once.

 

[JohnW2]

I thought that was a given.

Hmmm. I'm not sure that would get universal approval. We've even had people worrying about using a 30A JB in a 32A ring final! Although that's silly, I very much suspect that a good few people would have a problem with a 20A one, just as some do with a 20A (and 'not even to BS1363') DP switch!

Kind Regards, John

 

[Iggifer]

 

[SimonH2]

Notice they don't mention 221 connectors in the ratings table.

 

[Iggifer]

221s are fairly new so they may not have updated their information and moulding - or they’re just not suitable (don’t see why they wouldn’t be)

 

[JohnW2]

Thanks for the photo, Iggifer. I must say that, even now I know where to look, I can't see the MF mark on any of the eBay photos I've looked at!

221s are fairly new so they may not have updated their information and moulding ...

Indeed.

- or they’re just not suitable (don’t see why they wouldn’t be)

The shape/size of 773s and 222s is such that they are retained by the internal 'holder'. I don't think it would retain 221s, although I'm not sure why that should be a problem (after all, most of us usually use all Wagos 'loose').

Also, I'm not sure that I would see any advantage of 221s (over 222s) in a Wagobox, since there's no lack of space.

Going back to some of the early discussion in my thread about 221s, maybe this is a reason why 222s may persist, since I imagine that it would not be easy to modify the Wagobox so that the 'holder' could cope with both 221s and 222s/773s.

Kind Regards, John

 

[ban-all-sheds]

... and, as you can imagine, I am surprised by it. However, I think it yet again illustrates the fact that we really need to know a bit about what BS 5733 actually says!

I am likewise surprised and curious.

My surprise is mainly that a BS can work that way. It seems inconceivable that Connexbox would be lying, but wasn't our assumption that they were being, shall we say, a little sly in what they said, based on not finding the situation very satisfactory? i.e. "that can't be right"? That we have it confirmed it to be wholly above board does not, for me at least, change that.

For example, the combination of where the MF mark is, and the use of a cable tie. The say the mark has to be visible during installation, but surely the outside of the lid would be "visible"? I'm assuming the cable tie is because BS 5733 requires a tool to be needed to open it, so once installed anybody wanting to confirm BS 7671 compliance by verifying the presence of an MF mark would have to carry out a destructive operation. WOE not mark the outside of the box? Where are the Ashley J80x marked? WOE not design the Wagobox to be secured with a screw? A hole in the lid and a block for an installer-provided self-tapper would do.

And the whole hoop-jumping thing is a shame. This is a great solution for a loop-in rose replacement:

but not officially MF.

Neither is the use of the 224 connectors purpose designed to join solid-core fixed wiring and flex from lights.


Re the Wagobox XL and XLA general purpose boxes

They say "Use as directed in the BS 5733 MF instructions" - is that a claim of conformance? I see no MF marking inside the lids.

Hmmm. There are umpteen photos on eBay of Wagoboxes with their lids open, and, having tried quite hard, I cannot seen an 'MF' mark on any of them. Has anyone seen such an animal which does have this marking?

Again, we need to know about these requirements and tests.

It might have to be for BS7671 to revise its requirements.

Maybe it is BS 5733 which should be changed

 

[ban-all-sheds]

221s are fairly new so they may not have updated their information and moulding - or they’re just not suitable (don’t see why they wouldn’t be)

I've asked about that too, and the new 2273 push-wires.

I'm about to try their patience by asking about the XL/XLA JBs too...

 

[Iggifer]

Thanks for the photo, Iggifer. I must say that, even now I know where to look, I can't see the MF mark on any of the eBay photos I've looked at!

Maybe older stock doesn’t have them, I’ve only bought those within the last week. It’s also quite hard to photograph as it’s not impressed very deep.

Maybe the Wago retainer is the reason, but they could use some removable rubber inserts like they use for the cable clamp if they wanted to I suppose

 

[JohnW2]

Maybe older stock doesn’t have them, I’ve only bought those within the last week. It’s also quite hard to photograph as it’s not impressed very deep.

Indeed. All the photos I've seen show pretty different markings from what you have shown us.

Maybe the Wago retainer is the reason, but they could use some removable rubber inserts like they use for the cable clamp if they wanted to I suppose

Indeed. However, as I aslso said, I can't really see any particular reason for wanting to use 221s (rather than 222s) in a Wagobox, since there's no lack of space.

Kind Regards, John