Adding smoke alarms to lighting, replacing junction box

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Hi Everyone

I'm a first time poster and completely amateur diy-er.

I am intending to add smoke alarms to my upstairs lighting circuit. There is an old junction box with permanent live under the floorboards, which I am planning to carpet over. Picture here. (I have already replaced the really old cable.)

From reading here and elsewhere I understand that nowadays a junction box like this needs to be accessible, but it would be tricky to move this to a new location. The current box also doesn't have much room for the new cable.

I'm therefore hoping I can replace the box with a maintenance-free junction box. If that's correct, could please someone recommend a box that I could use?

Many thanks for any suggestions or advice.
Alex
 
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Regulations aren’t retrospective. As I understand.

But I wouldn’t want to be you.

I'm not sure I get your point... just that it's a mess? If so, that why I'm here , looking for advice...
 
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Well, it does, but I'm not sure how many you can get in one box.

With MFJBs the cables have to be restrained, i.e. by the cable clamps.

There appear to be only two connections with more than two wires - although there should be three, of course, with the earth wires. I would connect these while you are there even if they are not actually connected to earth at the supply. This can be rectified.
This would, of course, mean that the cables are too short if they are not able to be pulled nearer.


It's a bit of a pain of a job but you should do it properly while they are accessblie.


It's not a question of not requiring soldering. It is a better solution.
 
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Totally agreed I'd rather do it properly while they're accessible. I'm quite happy to solder them, but can just imagine it wouldn't be any neater, especially the joints between 4 or 5 cables... and I'd still need some way of clamping the cables for restraint right?

Earth wires are currently all joined around the back of the box. Unshielded and just twisted together.

I have the same question as you on wagoboxes - was hoping for advice on what size I might need.
 
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The earths all twisted together outside that box underneath? One cable I thought at first was Vulcanised rubber but the internal insulation looks like something else.
 
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Totally agreed I'd rather do it properly while they're accessible. I'm quite happy to solder them, but can just imagine it wouldn't be any neater, especially the joints between 4 or 5 cables...
Neatness is not the main concern.

and I'd still need some way of clamping the cables for restraint right?
You could put a piece of wood underneath and use clips - and have all the unsheathed wires in the existing box.


Earth wires are currently all joined around the back of the box. Unshielded and just twisted together.
Ah, ok. That's good.

I have the same question as you on wagoboxes - was hoping for advice on what size I might need.
I don't have much experience with them but I don't think you'll find one for, what, twelve cables and joints.
 
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Only if you have one switch which operates all the lights.

That doesn't appear to be what you have.
 
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Thank you for your suggestions everyone.

That screwfix box is exactly what I was looking at before I got looking into wagoboxes. But I must admit I don't understand how it works - I think it has a permanent live rail, operated by one switched line? In which case EFLImpudence is correct, it wouldn't quite suit this situation, unless I used several smaller ones.

Will keep looking for an off-the-shelf solution, but will keep the soldering idea as an option.
 
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I apologise - I have linked to the incorrect product above but the one I have previously used has a permanent supply (L&N) in and a permanent supply out (L&N) - hence you can chain multiple boxes together.

https://www.screwfix.com/p/surewire-sw4l-mf-16a-4-way-pre-wired-junction-box-white/2742j

The product above then has 4 switch connections and 4 corresponding light connections. This is the SW4L-MF and the wiring schematic is explained here: https://www.surewire.co.uk/products/light-and-switch-junction-boxes/products-and-benefits/

The one I previously linked to had one switch to operate all lights and I suppose is more suited to multiple downlights in one room.

upload_2019-3-21_14-34-43.png
 
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There is a 6 light one in the picture.

Thanks, I think that's where I went wrong when linking the original Screwfix item. I was looking for someone who supplied the SW6L-MF (1 in , 6 switches, 6 lights) and ended up linking to the SW6S-MF (1 in, 6 lights).

I can't seem to find a stockist of the former.
 
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