I want to take a spur off a downstairs ring main. By far the easiest way to do this will be to T-off the ring under the flooring, rather than from a socket. (I'm currently redecorating. so I can get to under the floor.)
I understand that I can't use a standard juntion box, as regs requires that screwed fittings need to be accessable. My question is - what sort of fitting should I use?
Thanks
Steve
This is that perennial question, what is 'accessable' in this context?
I think most would agree that under the floorboards it's usually OK to use a standard JCB, whereas (say) it wouldn't be OK to do it where the JCB is plastered into a wall.
David
You can get 'maintenance free' JB for this. Although, probably taking it from an existing socket would be better.
Thanks David. I have large sheets of flooring under the (future) carpet. I've managed to raise a sheet by removing a skirting board. I don't think in all honesty this could be called accesible. I know crimps would be used for joining cables in plaster, but I can't crimp a T-junction (or are special T-crimps available?!).. There must be an acceptable fitting for this sort of common situation, surely?
Steve
Thanks Slider. I did a search on "maintenance free junction box". This came up the Ashley J803 Maintenance Free Junction Box 32A 3 Terminal
Steve
An ordinary junction box, with a small access hatch above.
If you then put laminate over the floorboards, that's up to you.
Owain
Under floorboards is generally considered to be accessible. Even although it might be difficult to get to later - moving furniture, lifting carpets etc.
I favour not actually cutting the conductors of the ring when doing this - with care you can remove only as much insulation as needed to allow connection to the terminals. Of course this only works with the sort of JB that has slotted terminals. I'll leave it to others to guess how to insulate the earth conductor. ;-)
Think you need a new watch as well!! ;-)
Looks interesting - and just what I need when I remove a powerpoint but need to re-join the ring under the floorboards.
The blurb on the TLC site says that the contacts are 'screwless'. Anyone know how the electrical contacts are actually made?
It appears to allow 4 x 3 conductor cables to be joined - so I assume that each of the 3 conductors has 4 terminals which are permanently connected together? If this is the case, it presumably couldn't be used for lighting circuits where you want to break the live via a switch wire - 'cos that needs *four* independent terminals?
Ah - I see that they also do a 20A 4-conductor model, which sort of answers my question.
It still doesn't say how the cable ends are clamped though - anyone know?
I wasn't sold on this until I read (under 'Benefits') "Fits nicely in the hand" That convinced me!!
The terminals are push fit. A springy sharp edge clamps down on the wire. The same as wago connectors. See
Picture here:
they claim that: [[ The Maintenance Free junction box from Ashley is a junction box that has been manufactured to accommodate the increasing need to fit junction boxes in so called 'inaccessible' areas.]] and [[No other junction box provides as many features that allow Contractors to comply with the latest wiring regulations.]]
So they are saying that they are classed as crimping cables, not those screw in junction boxes which can get loose,
But have Building Inspectors officially passed them as such or could they demand to inspect them?
[g]
box".
called
If they are like the push in connections on some light fittings I'd avoid them like the plague, and certainly wouldn't want them under any floor of mine, accessable or not.
AWEM
In article , Roger Mills writes
It looks like they are spring clipped, it's a long established technique for high speed termination with terminal blocks. I remember the name Wago and "Cage Clamp" but their site is so awful that I lost the will to find a decent picture, you might get on better searching with those keywords.
Thought that myself when I saw the pic...
They can't be much better than the "screw caps" the yanks used to use!
In fairness, those screw caps were used here in the UK back in the '50's and early '60's. I remember them on the old conduit wires that were red cloth sheathing with a black tary layer below. Still don't like the idea of those push in connectors though. The first bit of slight overheating will take the temper from the springs that they rely on, then the arcing starts, followed by the blue flashing lights, sirens, men with hoses, and lots of insurance paperwork .
AWEM
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