Terminal blocks in sockets

[JohnW2]

I would question the relevance of their environments and their external influences to the environment inside my accessory back boxes and floor/ceiling voids.

Indeed - I have acknowledged that their practices relate to exceptionally high vibration environments.
However, that doesn't alter the fact that, in the fairly distant past, a good few of us were 'brought up' with the idea (wherever it came from) that one should not crimp solid conductors, even in ordinary terrestrial environments.

 

[amfisted]

View attachment 160419

Looking at that lot, I think I need a deeper back box.

 

[ban-all-sheds]

However, that doesn't alter the fact that, in the fairly distant past, a good few of us were 'brought up' with the idea (wherever it came from) that one should not crimp solid conductors, even in ordinary terrestrial environments.

And that requires recognition of the fact that there have been ideas of uncertain origin which people were brought up with which, upon proper investigation, turned out to have been nonsense.

 

[JohnW2]

And that requires recognition of the fact that there have been ideas of uncertain origin which people were brought up with which, upon proper investigation, turned out to have been nonsense.

Very true, but at least some of those ideas did have legitimate origins, even if those origins are now 'uncertain' to us (i.e. 'lost in history'). To dismiss them simply because we don't know where they came from is perhaps a bit hasty.

 

[rsgaz]

Looking at that lot, I think I need a deeper back box.

Those Wago 221 series are really tiny(slimmer than terminal blocks). I'd hazard a guess they were invented for going in back boxes, because the older 222 series are a bit clunky.



Show us a picture of what depth and wire slack you've got to play with?

 

[crystal ball]

Very true, but at least some of those ideas did have legitimate origins, even if those origins are now 'uncertain' to us (i.e. 'lost in history'). To dismiss them simply because we don't know where they came from is perhaps a bit hasty.

I must admit it is lost in a haze of Best Bitter and Newcastle Brown what the spec was but I still do not crimp solids, just one of them things

 

[JohnW2]

I must admit it is lost in a haze of Best Bitter and Newcastle Brown what the spec was but I still do not crimp solids, just one of them things

If one Googles the issue, there is certainly plenty of discussion out there about the acceptability (or not) of crimping solid conductors. Some personal views are very polarised, but I've seen no particularly definitive answer. Most of the detailed information on crimping out there seems to relate to large stranded cables.

It seems that BS 7609 is probably the relevant Standard, so anyone with a spare £126 could tell us what it says!

Kind Regards, John

 

[mattylad]

ISTR that the NASA and MOD standards would actually require the replacement of the entire wire should it be too short to terminate without lengthening it.

Can't have crimps failing when up in space or in the air you know, it's just not on

 

[JohnW2]

ISTR that the NASA and MOD standards would actually require the replacement of the entire wire should it be too short to terminate without lengthening it.

Yes, I can imagine that there might well be a prohibition of 'repairing' (rather than replacing) cables (by any means).

However, as I have shown, NASA have a 100+ page "Workmanship Standard" on crimping etc. - so one can but presume that it is a technique which is utilised (quite possibly only 'ab initio', rather than as a 'repair') in their field.

Kind Regards, John

 

[Edddd]

It seems that BS 7609 is probably the relevant Standard, so anyone with a spare £126 could tell us what it says!

I have checked out this standard via my work library and I can confirm:

• Your £126 will buy you 18 printed pages, 12 of which form the body of the document and one of those contains just one word: 'blank'.
• The word 'solid' does not occur in the document.
• Every diagram in the document appears to depict stranded cable

However:

This British Standard recommends methods and procedures applicable for the installation of uninsulated compression and mechanical connectors for use on copper or aluminium conductors of insulated cables conforming to BS EN 60228:2005 having a cross-sectional area equal to or greater than 10 mm² for copper and equal to or greater than 16 mm² for aluminium

 

[JohnW2]

I have checked out this standard via my work library ....

Many thanks.

... and I can confirm:........ The word 'solid' does not occur in the document. ..... Every diagram in the document appears to depict stranded cable ... However: ....

This British Standard recommends methods and procedures applicable for the installation of uninsulated compression and mechanical connectors for use on copper or aluminium conductors of insulated cables conforming to BS EN 60228:2005 having a cross-sectional area equal to or greater than 10 mm² for copper and equal to or greater than 16 mm² for aluminium

... which seems fairly consistent with my ...

... Most of the detailed information on crimping out there seems to relate to large stranded cables.

... and I doubt that there are (m)any cables ≥10 mm² which are not stranded.

Did that Standard give an intimation, or do you otherwise know, whether is is another relevant Standard for conductors <10 mm² - or is there simply no BS which covers such matters?

Kind Regards, John

 

[aptsys]

... and I doubt that there are (m)any cables ≥10 mm² which are not stranded.

Did that Standard give an intimation, or do you otherwise know, whether is is another relevant Standard for conductors <10 mm² - or is there simply no BS which covers such matters?

Kind Regards, John

Plenty >10mm² used by the DNO along with crimps...

 

[Edddd]

another relevant Standard for conductors <10 mm²

I have little knowledge of the Standards, so I'm just following cross-references.

BS 7609 references BS 4579-1:1970, which is about test specifications for compression joints: resistance, tensile strength etc.
The scope of that Standard has no minimum CSA but it does say:

The conductors for which the connectors may be suitable may be tinned or untinned, stranded or solid...

BS 4579-1:1970 has been superseded by BS EN 61238-1:2003, which explicitly refers to solid core conductors, but covers all mechanical joints and again only conductors 10 mm² or more in copper.

There's also BS 5G 178-1:1993: Crimped joints for aircraft electrical cables and wires. That makes no reference at all to solid core conductors, but it does mention strands of a core. It could be that solid core conductors are prohibited entirely in aircraft, which would seem sensible to me.

Are solid-conductor cables widely used outside of domestic wiring?
Transformers and other wound components? My experience is mostly of small examples and I can't recall seeing a crimped termination of a winding.
Telecoms? Those tend to be insulation-piercing, sprung blade type terminations.

 

[amfisted]

Those Wago 221 series are really tiny(slimmer than terminal blocks). I'd hazard a guess they were invented for going in back boxes, because the older 222 series are a bit clunky.



Show us a picture of what depth and wire slack you've got to play with?

Many thanks once more.

The following may not make sense, but I'll give it a go.
The MK socket that I originally tried to fit had terminal screws which were angled slightly inwards towards the front of the plate, and given the shortness of the cables this made it tricky to find the angle to get sufficient purchase on the screws in order to fix the wires. The neutral in particular simply wouldn't stay fixed in the terminal. The cheaper sockets that I've bought recently to replace other converters have terminal screws which are parallel with the socket plate, and even given the shortness of the wires, they are much easier to access with the screwdrivers that I possess.

If I still can't secure all the wires properly after trying a different socket, I'll look at the terminal block solution that you and others recommend and I'll also post pictures.

 

[JohnW2]

Plenty >10mm² used by the DNO along with crimps...

Do you mean solid conductors?

Kind Regards, John