Replacing old JBs under floorboards

[jhs14]

Moved house. Upon lifting floorboards I'm finding junction boxes on the ring final circuit all over the place - most of the wall sockets are on one ring and a lot of the downstairs sockets seem to be spurred off from the ring from old black JBs under upstairs floorboards.

I'm keen to sort these out as I see them rather than leave them alone, but I'm confused about the ideal way to join cables under floorboards (ie, inaccessible), I keep reading different things.

My thinking is to use wago connectors (222-413, the ones with the orange lever) and put them in choc boxes. But I've just got my hands on some choc boxes for the first time - they look a bit flimsy to me, maybe better suited to lighting circuits?

So is it better to use a standard empty enclosure (eg IP65) and clip the cables to the joist as strain relief? It just seems a bit cobbled together to me, compared to the trusty old junction box..

 

[diyer56]

Maintenance free junction boxes are available:
http://www.tlc-direct.co.uk/Products/ASJ803.html

 

[AndyPRK]

Or you could just leave them alone. They have probably been there for decades.

 

[diyer56]

Or you could just leave them alone. They have probably been there for decades.

This is what I did

 

[jhs14]

Or you could just leave them alone. They have probably been there for decades.

Indeed, they look as if they have! I'm well aware that, especially if I just check the screws are nice and tight, they'll last another twenty years. I just want to get it all done properly up to current regs. Though I have to say, having never used wagos before I don't feel any more confident about them than about screw terminals, being somewhat of an unknown quantity for myself. I realise electricians seem to like them though.

Whilst I remember, I have another, perhaps more troubling, query. Under my floorboards there are bare earth wires that are laid on their own (no sheath/insulation, just stranded wire) all across the room. I'm assuming that this formed part of the earthing system several rewires ago?

Fine, but they are still connected to the present wiring - for example, one of the JBs takes a spur off the ring. But as well as the three T&E coming out of the box, there's this bare earth wire that also comes out and disappears under the floor somewhere. My initial reaction is to recoil in horror and go around disconnecting these random earths, is this a bad idea? (The house is properly earthed, we have RCDs that work, all sockets and lights are earthed with properly identified cpcs)

 

[ericmark]

Theory is vibration can cause screws to become loose hence the maintenance free boxes but I have not found it with wooden floors. With metal structures yes but not with wood. I am sure some one will correct me!

But one asks why would you find so many junction boxes? My mothers house built 1954 had a grand total of 5 sockets when built and my dad added and added but in theroy 5 sockets can only extend to 11 sockets one from each existing and one from consumer unit and there are far more than 11 and I don't think my dad extended the ring he just fitted spurs.

So job one is to find what you have as it may be a case of altering wiring rather than simply replacing boxes and when you alter you may not need the junction boxes.

 

[jhs14]

I looked at the ashley ones - is there anywhere you can get them in real life rather than over the internet?

 

[jhs14]

Theory is vibration can cause screws to become loose hence the maintenance free boxes but I have not found it with wooden floors. With metal structures yes but not with wood. I am sure some one will correct me!

But one asks why would you find so many junction boxes? My mothers house built 1954 had a grand total of 5 sockets when built and my dad added and added but in theroy 5 sockets can only extend to 11 sockets one from each existing and one from consumer unit and there are far more than 11 and I don't think my dad extended the ring he just fitted spurs.

So job one is to find what you have as it may be a case of altering wiring rather than simply replacing boxes and when you alter you may not need the junction boxes.

Yes, where possible I've been getting rid of the JBs by incorporating the wiring into sockets. But there are some that are nowhere near any other accessories and the wire is too short to make any drastic changes - short of crimping an extension to the cable.

I'm probably exaggerating, I think I've found four JBs on the ring so far. There are more on the lighting circuit but that's more to be expected.

 

[plugwash]

Your options for a compliant inaccessible joint are basically soldering, crimping and use of approved "maintinance free" junction boxes.

Wagos placed in a generic box are not considered "maintinance free", they have to be placed in a special enclosure specifically designed so when used with them it meets the requirements for a maintinance free junction box.

Soldering is a good soloution if you are good at it but making solid reliable joints takes skill.

Crimping is widely used but it's reliability with solid conductors is somewhat questionable and it's not a good soloution where more than two conductors need to be joined (as is the case when spurring).

Probablly the best soloution is to use the ashley maintinance free junction boxes that diyer56 linked.

 

[plugwash]

I looked at the ashley ones - is there anywhere you can get them in real life rather than over the internet?

I expect most electrical wholesalers would be able to get them and may well have stock.

 

[bernardgreen]

When using "maintainance free" connectors on old cable be sure to clean the copper and remove all tarnish or corrosion before pushing into the connector.

Screw connectors where the screw rotates onto the wire will cut through the corrosion and make a good connection. Spring pressure contacts may not to displace enough of the the corrosion to make a connection able to carry the rated current.

Best option it to replace the cable and remove all the in-accessible junction boxes.