Correct way to joint 3 x 30 Amp cables, 30A JB not big enough

[fourtytwo]

Good evening everybody. I have a cooker feed from the CU that is then split under the floor above the kitchen to separate outlets for the hob & Oven. The problem is a standard 30A JB does not have big enough terminals to accommodate the wires. The person who installed this has cut some of the strands and one of the terminals appears cross threaded in the attempt. I am just about to close the floor permanently with wretched laminate and am not happy to leave this as is under the floor, any suggestions how to improve it ?

 

[westward10]

That joint will need to be 'maintenance free' and that joint box is not suitable. What you are trying to do is a disaster in waiting.

 

[fourtytwo]

That joint will need to be 'maintenance free' and that joint box is not suitable. What you are trying to do is a disaster in waiting.

Umm not what I am trying to do, I am trying to do the job correctly after discovering this under the floor!
Exactly what MF connectors are you suggesting are suitable ?

 

[Aaron b]

Those junction box terminals sometimes splay open as you torque them. As Westwood says a maintenance free box should be used if it's not going to be accessable.

I'm in Norfolk too btw.

 

[timhoward]

Umm not what I am trying to do, I am trying to do the job correctly after discovering this under the floor!
Exactly what MF connectors are you suggesting are suitable ?

Are they 6 sq mm conductors?
If so I'd be looking at Wago 221-613 3-way connectors, with each cable being clamped at point of entry to an adaptable box (Wiska or similar)

 

[DPG]

As above, you can't leave that junction box under the floor. Regardless of how well it is fitted.

 

[fourtytwo]

Are they 6 sq mm conductors?
If so I'd be looking at Wago 221-613 3-way connectors, with each cable being clamped at point of entry to an adaptable box (Wiska or similar)

Hi Tim, yup I guess there 6mm sq although they predate such measures being black & red insulation. Thanks for giving me the wago part# unfortunately the likes of screwfix only sell them in packs of 50 so now I just have to hunt down a source of a few and a box. We have a local electrical wholesalers but they will probably laugh at me but worth a try....

 

[loz2754]

Are they 6 sq mm conductors?
If so I'd be looking at Wago 221-613 3-way connectors, with each cable being clamped at point of entry to an adaptable box (Wiska or similar)

This method would not necessarily satisfy the requirements for MF connections.

 

[Aaron b]

You need to double check the part numbers as the do ones that only accept upto 4mm. Screwfix sell the right ones in packs of 30.

The wago XL box is only rated for 4mm cables but it's probably the best option.

 

[7029 dave]

Rewire it back to the CU in one continuous length, and use a duel plate to connect up your hob and oven.

 

[pc1966]

Hi Tim, yup I guess there 6mm sq although they predate such measures being black & red insulation.

The UK went metric in conductor size in the early 70s but did not harmonise colours to the current form for fixed wiring until around 2003 (I think)

Thanks for giving me the wago part# unfortunately the likes of screwfix only sell them in packs of 50 so now I just have to hunt down a source of a few and a box. We have a local electrical wholesalers but they will probably laugh at me but worth a try....

Be careful with "maintenance free" parts as often the box is only certified as MF with specific terminals and often with the addition of a cable tie to keep the lid in place no matter what.

Basically read the instructions carefully before you decide and act.

 

[fourtytwo]

Rewire it back to the CU in one continuous length, and use a duel plate to connect up your hob and oven.

Unfortunately domestic considerations get in the way of such an ideal solution.

 

[westward10]

Anything above 4.0 it starts getting difficult. I would solder butt the conductors and encapsulate the enclosure.

 

[pc1966]

These might be of help:

Quickfix JB3 Junction Box for Wago Connectors | Quickfix (JB3)

Wago 221 Compact Lever Splicing Connector 6.00mm - 3 Pole | Wago_Connectors (221-613)

Edit: Oddly TLC say 1-1.5mm cable but the data sheet says nothing - needs more investigation.

 

[fourtytwo]

Anything above 4.0 it starts getting difficult. I would solder butt the conductors and encapsulate the enclosure.

I must confess I have not actually measured it to know what cross section it actually is, whatever it is 3 lots of it simply dont fit properly in a 30A JB.

 

[westward10]

The lower left cable is no bigger than 6.0 but the other cable has tinned copper conductors and is likely to be imperial, above 6.0 but less than 10.0 judging by its apparent size.

 

[pc1966]

This one says 6mm and has MF instructions:

WAGOBOX XLA

Multipurpose electrical junction box with adjustable cable clamps

www.cef.co.uk

But only with this connector for 32A use:

3 Way 6mm Push Wire Connector Red (Pack of 50)

Push wire connector for junction boxes

www.cef.co.uk

A search around might find other cheaper suppliers, but in the grand scheme of things it is not too much to spend.

 

[pc1966]

The lower left cable is no bigger than 6.0 but the other cable has tinned copper conductors and is likely to be imperial, above 6.0 but less than 10.0 judging by its apparent size.

Well spotted sir!

Also the (presumably) plain green sleeving suggests that is probably per-1977 or there about.

 

[Aaron b]

A Knightsbridge 60amp junction boxes are much better than what you have but are not maintenance free/screwless terminals. I would use them in a loft when extending electric showers.

 

[westward10]

The suggested connectors are not likely to suit that cable, back to #13.