Wrong size cable.

[JohnW2]

Do you consider the 1.5mm² an instruction or merely information?

Well, as far as 'regs' are concerned, it no longer matters that much - since, even if intended as an 'instruction' one only has to "take it into account".

If an instruction, then for what reason?

I've made one suggestion (terminal capacity) - but MK's instructions/information about terminal capacity (e.g. for sockets) tend to be a bit odd!

Would it be heresy to suggest that the strands could be cut to accommodate the conductor?

I don't doubt that many would count it as 'heresy'. The practical worry would be whether people would necessary ensure that they left enough strands to represent an adequate CSA.

Kind Regards, John

 

[Echo the husky]

I have a 10mA RCD here with a socket in it wired in 2.5mm yy flex with an MK plug on the end. The nut type terminals are more than big enough but it looks like I pulled out one of the cable grip things to get the flex in, and it is still a tight fit. I would have thought most plug top terminals would take a 2.5mm conductor if it was put straight in, without the need to cut out strands which is a terrible and shoddy thing to do!

 

[EFLImpudence]

without the need to cut out strands which is a terrible and shoddy thing to do!

In the normal course of events and detrimental to requirements, yes -

but if the wire is twice as big as needed, what harm?

 

[SimonH2]

I would have thought most plug top terminals would take a 2.5mm conductor if it was put straight in, without the need to cut out strands which is a terrible and shoddy thing to do!

I was thinking that - I don't think I can remember wiring a (13A) plug that wouldn't have taken 2.5mm² cable in the terminal holes. The "post with nut" style old plugs might be a different matter, but all the "hole and grub screw" ones have had a hole big enough for the copper. As suggested, managing the physical size of the cable would be a different matter.
Personally, I would not fail something for having "too large" cable - only if the size of the cable meant that there were other problems - such as fitting it into the plug correctly.
PS - I do know that if you try hard, you can get 4mm² flex into a 13A plug. With a mate we bought a "good sized" MIG welder from a friend when he was shutting up shop. Before I got the bits together to do an adapter and leave the 32A blue plug on, my mate had already changed it to a 13A plug. Hmm, that reminds me of a little job I'd forgotten about ...

 

[EFLImpudence]

plug top

 

[Echo the husky]

I thought I'd slip that in there.

 

[Echo the husky]

In the normal course of events and detrimental to requirements, yes -

but if the wire is twice as big as needed, what harm?

I just couldn't do it, would use a reducing pin crimp.

 

[EFLImpudence]

 

[EFLImpudence]

The smiley was for your previous post.

We seem to be short of debating points tonight.

 

[JohnW2]

I just couldn't do it, would use a reducing pin crimp.

Wouldn't you struggle to get that into the space available within a plug, particularly when the conductors were quite large?

Kind Regards, John

 

[Echo the husky]

I wouldn't shove huge cables in a 13A plug! There is rarely need for anything bigger than 1.5mm to go in a plug, though 2.5 is quite often seen on long extension leads, especially around marquees etc.

 

[JohnW2]

I wouldn't shove huge cables in a 13A plug! There is rarely need for anything bigger than 1.5mm to go in a plug, though 2.5 is quite often seen on long extension leads, especially around marquees etc.

CCC-wise, there's probably never going to be a need for bigger than 1.5mm² (probably 1.25mm²) - but, as you imply, there might be such a need in terms of VD on very long cables.

Kind Regards, John

 

[deadshort]

We have a contractor in work carrying out PAT work. He has failed an appliance which, whilst not strictly being portable in that you can carry it around, is connected via a BS1363 plug.
His reason is that the 2.5mm 3 core cable is too large for this plug and the maximum diameter should be 1.5mm

Is this correct and is he right to fail it?

Difficult to tell unless we can see the physical condition of 'this' plug. An appliance can be electrically safe but physically damaged in which case it should be failed.

DS

 

[SimonH2]

Yes but that would make the reason for failure "damaged", not "cable too big".

 

[Risteard]

It is absolutely correct to fail an appliance connected with 2.5mm^2 cable into a BS 1363 plug. It is a prohibited arrangement.