Overloaded fused spur, opinion please

gkenyon:

perspicacious:
This is the same question re Wago's ? Provided the terminals are sized for either 2x2.5 sq mm or 2x4 sq mm, surely there's not an issue here?


Until that is answered, there's no point in adding further asides unless a career in politics is looming?


Again, simply, are the INPUT/loop in terminals of a 20 A DP switch suitable for connection to a 32 A RFC irrespective of whatever is on the OUT terminals?


Regards


BOD

 

Provided the manufacturer's information shows that the conductor sizes for the terminals are suitable for 2 x 2.5 or 2x 4 sq mm, I don't believe there's a problem. Many of them are suitable for the same conductor configurations as BS 1363 accessories.


Is there any reason to conclude otherwise?


So, I checked - BS EN 60669-1 is being used for switches now, not the general standard BS 5733.


20 A switches are tested for temperature rise with a current of 25 A, which is broadly in line with the tests for BS 1363 accessories.

BS EN 60669-1 and BS 5733 are similar. For accessories > 16 <= 25 A, the terminals must accommodate 1.5 to 4 mm² (5733) or 2.5 - 6 mm² (60669-1) solid conductors. Whilst the terminals may accommodate more conductor, clearly it must still be possible to clamp the smallest one adequately. If a 60669-1 terminal can accommodate a 6 mm² conductor, it seems pretty obvious that it will accommodate 2 x 2.5 mm². Regarding looping in and out, or being placed in a ring, the rating is that of the switch. I see no reason why any terminal which will accommodate 2 x 2.5 mm² should not also safely carry the load (up to 27 A, RM C).


As Graham says, manufacturer's instructions are what count. Some 20 A switches may be inserted in a ring, some may not.


My preference is to spur off the nearest socket in 2.5 mm² and put the switch into the spur.


I would have no reservations about using Wagos of the appropriate rating in an appropriate enclosure. A back box would not be adequate for a fully loaded cable.

perspicacious:

Wago 773-104

Max 2,5 cable

Terminal current rating 24 A


However, Table 4D5 Method C for 2.5 cable gives 27 A


27 A > 24 A

You could use the bigger Wagos which accept 2.5 - 6 mm² and are rated at 41 A. However, inside a Wagobox, IIRC, the rating is reduced to 32 A. IMHO, perfectly suitable for branching a radial circuit.

perspicacious:

I didn't want to spoil the terminal rating topic on a RFC by reminding readers of content of 433.1.204 regarding CCC of 20 A being satisfactory.....


So, with this in mind, would a 20 A JB attract any coding on an EICR if found on a 32 A RFC?


Regards


BAD

Interesting ... 433.1.204 relates only to the current carrying capacity of the cable and not accessories (except being "permissive" for BS 1363 accessories as we discussed previously) ... which brings an interesting dimension to the tale, but I think that's now getting very picky ... it will be interesting to see what others think about the 20 A JB question.

davezawadi (David Stone):

I think that we are getting ridiculous here. Wagos or Ideal similar, to what BS are they made?Personally, I like the USA twist connectors but no BS although they are very good and robust, far more so than Wagos. The terminals in a 20A junction box actually carry practically no current, all they do is clamp the conductors together. Whilst I do use Wago types sometimes, I am not really very keen because the wires are not prevented from rotating, Springs of any kind are not my favourite way of holding things, they potentially do not make gas-tight connections. I, therefore, have a problem with an EICR, in that non-BS parts are used in an installation I have to take 133.5 into account and am probably contrary to 133.1.1 and 133.1.2 unless I explain to the customer.

 

Nonsense. Wagos are certified, for example the 773 series we've been talking about have certification to EN 60998 series - all you need to do is look on the manufacturer's web-site.


And EN 60998 series are BS's too ... https://shop.bsigroup.com/SearchResults/?q=60998

davezawadi (David Stone):

Now to BODs switch, the same consideration as the junction box clearly applies, the terminal carries little or no current, the wires are clamped together, and in some cases twisted too. The terminals do not have a current rating except where they leave the clamp mechanism and become connections to the accessory mechanism. How many wires will fit the terminal has nothing to do with this, in fact the fuller the terminal the higher the current rating will be because of all the touching areas of the conductors.


Perhaps BOD is being BAD BAD again!

Agreed, except I don't think BOD is being BAD, just making some points that appear to have gone round the "industry rumour mill" ...