Peter, now I am confused: I imagined a chap called Hugh who is thin on top. (By contrast, like Esau, I am a hairy man.)

I think a pull test and a resistance test, i.e. ring continuity are about the best that you can do. I can recall doing a ring test (by then you have screwed the sockets on to the wall) which was open circuit. The posh (and expensive) wooden sockets had poor quality innards and one of the 2.5 mm² (or was it the smaller CPC?) had not been gripped properly. Perhaps this is why some folk double up their terminations?

At the other end of the scale, BS 1363's requirement is for the terminal to accept 8 mm², which is fine for a ring and a spur, but not adequate for a radial and a branch in 4 mm². Happily, the better manufacturers such as Hager and MK make terminals which will accept 12 mm².

Chris

I particularly dislike the square type terminal that comes on most sockets and spurs nowadays. If you try to put your wires in the middle, once tightened they invariably slip to one side with one being gripped more than the other. The round ones were the best where the wires were forced together in the centre and gripped equally. I find that trying to place each wire in opposite corners of the ‘square’ then the screw pushes between them and forces them into the corner rather than having the wire directly under the screw. I also think that manufacturers should state the minimum cable sizes as they are just as important as the maximum.

Baldyhugh said:

Probably more the minimum size actually.

How do you determine that?

Baldyhugh said:

Take a standard socket outlet or spur

BS 1363-2 states the following:

Terminals in rewirable portable socket‑outlets shall be of screw‑type and permit the connection, without special preparation, of flexible cables having nominal conductor cross‑sectional areas of 1 mm² and 1.5 mm² as given in BS EN 50525‑2‑11:2011 and BS EN 50525‑2‑12:2011.

If the the product can't achieve that, then it does not conform to BS 1363 (and hence the Plugs and Sockets (Safety) Regulations)

Hi Graham

That’s the point. The larger cables are less of a concern as the installer knows that they will be well secured in the terminal. The smaller however may be too small to be gripped securely by the screw hence either the manufacturer tells you or you use some technical judgement and do a pull test. Wago’s for example give a minimum and maximum size of cable that can be used.

Baldyhugh said:

Wago’s for example give a minimum and maximum size of cable that can be used.

So does BS 1363 series. For example, in addition to the example for portable socket-outlets posted yesterday, BS 1363-2 does not guarantee that fixed socket-outlets can accept anything less than 2.5 sq mm for line conductors, and 1.5 sq mm for cpc's !

Which implies that to terminate 1.5 sq mm line conductors into a BS 1363-2 fixed socket-outlet with screw terminals, "doubling back" is perhaps required, unless the manufacturer says that the terminals will take 1.5 sq mm ?

Do the socket-outlets made by MK with Wago-type lever terminals fail to comply with BS 1363? After all the terminals are not of screw-type. (Unfortunately I don't have a copy of BS 1363 to check.)

RB1981 said:

Do the socket-outlets made by MK with Wago-type lever terminals fail to comply with BS 1363? After all the terminals are not of screw-type. (Unfortunately I don't have a copy of BS 1363 to check.)

BS 1363-2 covers screwless terminals as well. In this case, the same Clause applies to screwless terminals. There are (understandably) certain provsions in the standard that are unique to screwless terminals and some unique to screw terminals (for example, tightening torque requirements for screw terminals make no sense for screwless terminals).

I couldn't make the same statement about "doubling up" with screwless terminals, though !

The MK rapid fix sockets states that it accepts 2.5mm2 and 4mm2. I presume that they are talking about t&e, again they are not specific enough. Just says ‘accepts 2.5mm2 and 4mm2’. If not then 2.5mm2 t&e won’t comply due to 1.5mm2 cpc.

Baldyhugh said:

If not then 2.5mm2 t&e won’t comply due to 1.5mm2 cpc

I think the cpc would have to comply with the requirements for cpc terminals, and the manufacturer is talking about csa in terms the live conductors of a UK  2.5 sq mm installation cable (6242Y) which has a reduced cpc (because we usually call this 2.5 T&E in the industry).

I would ask the manufacturer.