Lighting circuit central box

[iep]

Need to update an old lighting circuit where all lights and switches wire back to a central box rather than being arranged in a ring. Essentially we're just adding a couple of extra switches and light fittings to the room.

Only issue is that I can't find a replacement for the existing central box (which is no longer big enough. The old box is a metal unit with grommets in and out and a stack of terminals inside that allow easy configuration of circuits (2 switch etc).

Any idea where I might find a similar product?

iep

 

[Chri5]

How many cables?

Why do you suggest it's normal for lighting circuits to be ring wired? What sort of room is it, meeting room / commercial or house?

Flush or surface box, on show or hidden in a void, riser or loft?

 

[iep]

Only say ring lighting is normal since it is widely used in new builds. Personally, I prefer the approach taken here.

It's for an open plan living dining/area in a house. There will be around 8 light fittings and three triple switches so a fair few wires. Box will be mounted between joists in ceiling and be accessible from the loft above the room. Joists are deep so no issue with 50mm clearance above and below.

Surface box would be fine or a flush one that I could set into the flooring in the loft.

Cheers,

iep

 

[Chri5]

http://www.tlc-direct.co.uk/Products/BX4415.html

Would be fine, rather than grommet and have ingress problems with water or insects why not use



http://www.tlc-direct.co.uk/Main_Index/Cable_Accessories_Index/Gland_Compression_Nylon/index.html


Might be a bit ott to use a din rail, so I'd suggest connectors, or if you want

http://www.tlc-direct.co.uk/Main_Index/Cable_Accessories_Index/Wago/index.html

 

[Taylortwocities]

You could rewire the whole shooting match and eliminate the junction box.
If this is impractical (or too difficult) I would suggest just taking a live, neutral and earth feed to your new switch and loop the live feeds in the switch box.

In the old days a junction box under the floor was the norm. Todays regs say that any junction box must be accessible which yours may not be once carpet and/or laminate flooring has gone on top.

 

[iep]

I actually quite like the junction box approach and fortunately, the box will always be accessible.

Chri5, I like the look of the KO Box and sealed grommets but the WAGOBOX stuff looks fairly OTT to me. In the existing box they just used terminal block. Is there any issue with replicating that approach provided it's all nicely bolted down?

Cheers,

iep

 

[bernardgreen]

Terminal blocks need a bit of care when fixing them to the panel. If the fixing screws are too tight then the nylon / plastic can over time deform leading to a breakdown of the insulation.

Use a screw diameter that is a loose fit in the mounting hole and use a nyloc nut tightening the screw to the point that the screw holds the block but does not deform it.

Klippon terminals on a DIN rail can be linked by a bus bar along the top avoiding the need to have several wires in one terminal. They can also be labelled making future up-grading and fault finding much easier.

 

[scousespark]

Terminal blocks need a bit of care when fixing them to the panel. If the fixing screws are too tight then the nylon / plastic can over time deform leading to a breakdown of the insulation.

Have you ever seen this happen?

 

[bernardgreen]

If the fixing screws are too tight then the nylon / plastic can over time deform leading to a breakdown of the insulation.

Have you ever seen this happen?

Yes, breakdown between live and earth via the head of the screw that had cut into the nylon, and I have done it myself on an ELV control circuit when I didn't have the right size bolts to hand and impatiently forced a 4 mm bolt through a 3 mm hole in the block.

 

[EFLImpudence]

http://export.rsdelivers.com/product/rs/j701/12-way-rectangular-junction-box/2627893.aspx#header

 

[ban-all-sheds]

Only say ring lighting is normal since it is widely used in new builds.

Is it?

Don't think so...

 

[securespark]

Ring lighting is widely sold in sheds....

 

[ban-all-sheds]

 

[RF Lighting]

And it's made in Leeds

 

[scousespark]

If the fixing screws are too tight then the nylon / plastic can over time deform leading to a breakdown of the insulation.

Have you ever seen this happen?

Yes, breakdown between live and earth via the head of the screw that had cut into the nylon, and I have done it myself on an ELV control circuit when I didn't have the right size bolts to hand and impatiently forced a 4 mm bolt through a 3 mm hole in the block.

I have seen plenty of instances where the screw damages fittings, but the damage is instant. I have not seen a terminal block deform over a period of time.