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

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Discuss Correct way to joint 3 x 30 Amp cables, 30A JB not big enough in the UK Electrical Forum area at ElectriciansForums.net

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fourtytwo

fourtytwo

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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 ?
 

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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.
 
westward10 said:
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.
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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 ?
 
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.
 
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fourtytwo said:
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 ?
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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)
 
As above, you can't leave that junction box under the floor. Regardless of how well it is fitted.
 
timhoward said:
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)
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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....
 
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.
 
fourtytwo said:
Hi Tim, yup I guess there 6mm sq although they predate such measures being black & red insulation.
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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)
fourtytwo said:
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....
Click to expand...
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.
 
Anything above 4.0 it starts getting difficult. I would solder butt the conductors and encapsulate the enclosure.
 
westward10 said:
Anything above 4.0 it starts getting difficult. I would solder butt the conductors and encapsulate the enclosure.
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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.
 
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.
 
This one says 6mm and has MF instructions:
www.cef.co.uk

WAGOBOX XLA

Multipurpose electrical junction box with adjustable cable clamps
www.cef.co.uk
But only with this connector for 32A use:
www.cef.co.uk

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.
 
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.
 
I admit this is more complicated that I thought, and this has been a good wake up call!

Now the older cable has been pointed out I do think it might be better to rewire it, as suggested a long time ago.

It might also be possible to just crimp two of them, dispense with the 3rd, and run to a dual plate.
 
Aaron b said:
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.
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Yes, there are a few 60A rated boxes with cable clamps that should take those cables, but as you say they are not MF so would need to be kept in an accessible location.
 
It might be better to look at extending the supply cable using the correct size crimps and heat-shrink, and then putting any junction in an accessible location, or better still having it join at points such as cooker switches, etc.

However that would need proper crimp tools, etc, so really you would be better to get a professional in to do it.
 
So you are adding a third cable.
 
pc1966 said:
It might be better to look at extending the supply cable using the correct size crimps and heat-shrink, and then putting any junction in an accessible location, or better still having it join at points such as cooker switches, etc.

However that would need proper crimp tools, etc, so really you would be better to get a professional in to do it.
Click to expand...
Much as I agree with you I have just had a professional do a part P rewire and this is one of the issues I am left with.
 
Aaron b said:
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.
Click to expand...
It seems your answer wins Aaron as there are no MF products that fit this cable and will certainly be streets ahead of what's there at the moment, thankyou.
 
fourtytwo said:
Much as I agree with you I have just had a professional do a part P rewire and this is one of the issues I am left with.
Click to expand...

You haven't had a 'part P rewire' as there is no such thing.
What work did they actually carry out?

If you believe you have had a full rewire carries out then you need to take this matter up with the person who did it!
 
7029 dave said:
Rewire it back to the CU in one continuous length, and use a duel plate to connect up your hob and oven.
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This has to be the only real option
fourtytwo said:
Unfortunately domestic considerations get in the way of such an ideal solution.
Click to expand...
If you can't rewire it then ditch the laminate and use a floor covering that allows the junction box to be accessable when making considerations safety comes first and nothing should get in it's way
fourtytwo said:
Much as I agree with you I have just had a professional do a part P rewire and this is one of the issues I am left with.
Click to expand...
And how did you assess this person to be a professional. From your past threads the theme seems to be to keep the costs as low as possible and cut corners to suit yourself so was this a cheap rewire and you only got what you wanted to pay for or did you get proper advice from a qualified professional and................ignore it or more likelydid the professional you hired quit the job while he was ahead because of you demands
 
fourtytwo said:
It seems your answer wins Aaron as there are no MF products that fit this cable and will certainly be streets ahead of what's there at the moment, thankyou.
Click to expand...

It's a fire risk, which would defeat the purpose of what you previously set out to achieve.

Not much point ridding the house of rubber cable due to risk of fire, then burying a screw terminal joint under combustible material.
 
pc1966 said:
These might be of help:

Edit: Oddly TLC say 1-1.5mm cable but the data sheet says nothing - needs more investigation.
Click to expand...
I looked into this when I had to extend some cables, and Wago don't seem to do an MF enclosure suitable for the 221-612/3 range, which seems like a gap in the market.

The normal (original) Wagobox is fine for the 773-173 as MF, though 3 cables would be right on the limit of what it can take physically. Also only rated for 32A.

The Quickfix JB3 is a new product by a small company, designed for lighting only - they were at ELEX earlier this year. I've used it a couple of times and it's neat in the right circumstances.
 
Dartlec said:
I looked into this when I had to extend some cables, and Wago don't seem to do an MF enclosure suitable for the 221-612/3 range, which seems like a gap in the market.

The normal (original) Wagobox is fine for the 773-173 as MF, though 3 cables would be right on the limit of what it can take physically. Also only rated for 32A.
Click to expand...

Even the XL box would need the cable grips removing for 6mm and for maintenance free use the wagos are de-rated to 20amps. There's not an ideal solution here beyond rewiring it. Rewiring is the best solution considering the 50 year old cable.
 
I don't know why I bother with this site. It seems to have a fairly large contingent of conceited individuals intent on handing out insults that completely destroy the efforts of the few nice helpful people. Please delete my membership.
 
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fourtytwo said:
I don't know why I bother with this site. It seems to have a fairly large contingent of conceited individuals intent on handing out insults that completely destroy the efforts of the few nice helpful people. Please delete my membership.
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You keep on asking professionals for their opinion and when it is not what you want to hear you post this, REALLY!! grow up and get a life
Your safety and the safety of others seems to rank very low on your list of priorities with your bodge it and scarper, ignorance is bliss attitude I just hope it doesn't catch up with you and those you put at risk with your David Dickinson DIY electrics
 
what insults??? i not seen any since the wife woke up this morning.
 
fourtytwo said:
I don't know why I bother with this site. It seems to have a fairly large contingent of conceited individuals intent on handing out insults that completely destroy the efforts of the few nice helpful people. Please delete my membership.
Click to expand...
It is your property so do as you please. Members on here offer solutions in compliance with current standards, free solutions I add as you seem opposed to actually paying for a trades person. Your property and your life at risk, thread closed.
 
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