Permitted methods of joining t&e

[smp50]

Hello. I can't seem to find a clear answer to this. I've discovered a few things that are and are not allowed, but not a clear list of options.

How may one join two lengths of t&e end to end? I gather that it depends if the joint will be accessible or not.

In my particular case the cable and joints will all be under floorboards. I don't have a crimping tool, can I just use this sort of thing?

http://www.screwfix.com/p/30a-3-ter...tracking url&gclid=CM_Eosyf_LQCFebLtAodNgYAmw

Or do they need to be left accessible?

Thanks,

 

[Iggifer]

that kind of JB needs to be accessible.

You can use:

http://www.tlc-direct.co.uk/Products/ASJ803.html

 

[smp50]

that kind of JB needs to be accessible.

You can use:

http://www.tlc-direct.co.uk/Products/ASJ803.html[/QUOTE]

Thanks, ok.

So is it either a case of crimping or using a specific mainentance-free type of junction box? I guess those are the only two broad options, anyway.

Is this kind of enclosure acceptable?
http://www.wickes.co.uk/invt/199778/?source=123_75

How does one determine whether a particular junction box or similar device is OK to leave inaccessible?

I'd be uncertain of my crimping if I tried it, and wouldn't know if I had wrapped the joint properly afterwards. At least with screw-down stuff it should be no worse than me wiring a socket or switch.

 

[Iggifer]

The ashley JB's have no screws, that's the point, they're sprung clips.

So you strip the wire, and push it in, job done.

If you're jointing an already stripped cable, i'd cut back a few mm and re strip, just so you've got a nice clean, straight piece of conductor to put in, not one that's been mangled by a screw terminal

 

[smp50]

The ashley JB's have no screws, that's the point, they're sprung clips.

So you strip the wire, and push it in, job done.

If you're jointing an already stripped cable, i'd cut back a few mm and re strip, just so you've got a nice clean, straight piece of conductor to put in, not one that's been mangled by a screw terminal

Will do, thanks for the tip.

Are sprung connectors the important feature of maintenance-free junction boxes?

 

[JohnW2]

I'd be uncertain of my crimping if I tried it, and wouldn't know if I had wrapped the joint properly afterwards. At least with screw-down stuff it should be no worse than me wiring a socket or switch.

Easier, in fact - those maintenance-free JBs have 'push-in' terminals - so there's not even any terminal screws to tighten (hence no doubts as to whether you may have undertighted or overtightened the screws).

Kind Regards, John
Edit: I must learn to type faster!

 

[JohnW2]

Are sprung connectors the important feature of maintenance-free junction boxes?

One of the most important features, yes. Cable clamps are another.

Kind Regards, John

 

[smp50]

Ok, thanks. So basically if I get something with sprung connectors and cable clamps, that obviously closes up fully as well, then it should be OK to leave under the floorboards?

It does seem to me that a spring arrangement is more likely to degrade and fail over time than screws. Don't you think?

 

[JohnW2]

Ok, thanks. So basically if I get something with sprung connectors and cable clamps, that obviously closes up fully as well, then it should be OK to leave under the floorboards?

No, you can't just get 'something' which has those features. It has to be designed and tested to be maintenance-free and bear the 'MF' marking. As far as I am aware, the only currently available are the Ashley ones (per link above) and Wago connectors in a Wagobox.

It does seem to me that a spring arrangement is more likely to degrade and fail over time than screws. Don't you think?

Apparently not. The copper of the wires can gradually 'squash' (compress) over time, leading to screw terminal connections becoming loose. Spring terminals, however, automatically compensate for such changes and therefore maintain the required pressure on the conductor.

Kind Regards, John

 

[smp50]

Makes sense, thanks.

I'll see what further access I can get to existing sockets and cables and if I can devise a viable way to do this wiring with no joints out of the sockets, I will.

 

[AdamCH]

If you use a maitenance free box on a lighting circuit to contain the switching etc and then hide it away. How will someone inspecting the wiring later know that the JB is maintenance free?

 

[Scoby_Beasley]

If you use a maitenance free box on a lighting circuit to contain the switching etc and then hide it away. How will someone inspecting the wiring later know that the JB is maintenance free?

It should be on the schematic drawing that should be left next to your cu, or a reference next to the cu as to where the previous owner/occupier stashed it away for safe keeping (never to be seen again!!)

 

[Johnmelad]

No, you can't just get 'something' which has those features. It has to be designed and tested to be maintenance-free and bear the 'MF' marking. As far as I am aware, the only currently available are the Ashley ones (per link above) and Wago connectors in a Wagobox.

For the OP - not all wago boxes are Maintenance free. The box must have the MF marking

 

[AdamCH]

If you've hidden it away and can't see it you could just say it is - on the schematic ... that 's been lost

Isn't the problem with Wago boxes that you can open them without a tool?

 

[JohnW2]

If you use a maitenance free box on a lighting circuit to contain the switching etc and then hide it away. How will someone inspecting the wiring later know that the JB is maintenance free?

They won't, unless they are told (e.g. by being given a wiring diagram) - any more that they would know that there was a non-MF JB in an inaccessible place (unless they took the house apart). That's why I'm personally no fan of any sort of inaccessible joints - but the regs now allow MF JBs (and always have allowed crimped/soldered etc. joints).

Kind Regards, John