Joining solid core to twisted cable

[PingCrosby]

Hello,

I have 6 wires all twisted cable and i need to join these wires to 2 x twin & earth solid cable.. Not able to find a 6 core cable

Because the wires to be joined are different thicknesses I do not believe a safe connection can be made directly with a 15amp chock box. I am looking for a small junction box as the space this has to fit into is extremely small.

Does anybody suppy a junction box that can take these wires

Thanks

 

[rebuke]

I assume 2 of your 6 wires are earths then, as you really shouldn't use the unsheathed CPC in T&E for anything else...

You don't mention what current the cables will be carrying, which affects the type/size of junction box required, I assume less than 15A since you mention it, but how much less?

Important thing with joining stranded and solid conductors (which it seems you've already realised), is do NOT do it in the same terminal, i.e. try and use one screw to hold both the solid and stranded conductor. There are various things available - looking here (http://www.tlc-direct.co.uk/Main_Index/Wiring_Accessories_Menu_Index/Junction_Boxes/index.html) - I can see a number of options, theres an MK junction box with multiple terminals on each, or maintenance free ones etc. Your other option of course is assuming the conductors in the stranded and T&E are the same CSA (cross sectional area), to just join them with crimps inside a box of some sort...

 

[PingCrosby]

Thanks for the reply - to clarify

It is an 240v appliance ~5amps . I am fitting a control unit to the appliance by "extending" the internal wiring and the only extension cabling i have is T&E 1.5mm solid core.

As there are 6 wires and the extension control unit has no earth anyway I am using all cables (eg 2 runs of T&E to connect to the original 6 wires).

Looking at ://www.tlc-direct.co.uk/Main_Index/Wiring_Accessories_Menu_Index/Junction_Boxes/index.html i cannot find anything that suits my needs

Ideally i want a small screw for the thin cable and large screw for the thicker cable and some kind of bridge/bar to make the connection. Also i would prefer it was a 6 way connector. (sorry for my odd description)

The wires sadly do not have the same cross sectional area so I feel crimping would not be an option unless i can a small "crimps" that can connect to larger amp'age crimps - hmmm does that make sense

 

[PingCrosby]

Doh

I am an idiot..did not scroll down the page link you sent me .. Think i found the one i need

"Ashley J804 Maintenance Free Junction Box 20A 4 Terminal" This will take the 6 wires and i can mix the cable thicknesses

Thanks

 

[rebuke]

If you get the right T&E (if it's 5A then 1mm would be fine), you should be able to just get a strip of 5A connector block, and use that - the screws *should* be able to secure a stranded cable one side, and a solid the other.

Note thought that as I've said, using the CPC (earth) conductor of T&E for anything other than earth/CPC, is a very bad idea. Anybody working on the cabling in future would assume it to be earth, not a live conductor, it's not double insulated (as in it only has the overall sheath protecting it, unlike the other conductors which have their own insulation as well), and it's normally of a smaller diameter than the other cores (which is fine as a CPC, but not for a live conductor).

You could do two runs of three core & earth, at which point it would be fine, but don't use the earth conductor in normal T&E...

 

[aptsys]

http://www.tlc-direct.co.uk/Main_Index/Cable_Index/Flex_7_Core_Grey/index.html

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

 

[PingCrosby]

Point noted - about the T&E and my misuse of the earth.

The controller basically receives L+N and returns 2 switched connections back to the appliance. So yes i use the earth as a live conductor..

I figured that since the T&E is alot thicker (even the earth) than the original cabling it would not be an issue (even the earth sheathing is thicker). However I am extending the wiring by about 2.5 metres so I guess this is when it comes into play.

Happy to change the wiring if you think this would be an issue.

One further note, i have marked the cabling with coloured tape to match original wire colour coding. So hopefully no can assume its an earth.

Thanks for your help

 

[aptsys]

You must not use the earth as a live conductor.

If you must use twin and earth rather than the flex I suggested then run three lengths and only use the double insulated wires as line conductors.

 

[rebuke]

Unless your cables are running inside conduit / trunking, then the wiring regs say that any live conductor should be insulated and sheathed (dont have copy of the regs on me to look up the exact reg), the earth is only sheathed, so therefore your cabling doesn't comply, so you really should change it...

 

[PingCrosby]

Gaddam it guys - you post to fast for me

Going to replace the wiring with 0.75mm 7 Core Pvc Flex Grey, this should be ample to carry a 3metre extension of the internal wiring to my control unit and it has the added advantage that i can wire this directly into the existing mains block on the appliance.

I wanted this type of cabling originally - the T&E (fix) was a best fit at the time.

I cannot find this anywhere at B&Q does anybody know anywhere else other than TLC i can this cabling from ?

 

[PingCrosby]

All

Would the cable 0.75mm 7 Core Pvc Flex Grey be ok to use for a central heating timer ?

Does it need to be heat shielded ?

Am thinking of using this cable to extend my boiler controller?

 

[RF Lighting]

www.competentperson.co.uk/search.asp