If our consumer unit is moved by about a metre/3' 3" the upstairs circuit cables would be too short to reach the CU. Would all the upstairs cables have to be replaced or could the cables be extended by jointing cables?
They could be extended, for example by crimping, using a *proper* ratchet crimping tool like this
Not a cheapo tool like this
A very neat example of one method shown here.
I think I have one of the ratchet crimpers or it might be a CAT5/6 tool. I'll check.
Yeah, that's neat. Presumeably if we go down that route, the small box would be at the end of the existing cables and the new cables would come from the small box to the CU?
If they're pre-insulated crimps and you're not Drivel-inept at using them, there's sod-all difference.
In article , Andy Dingley writes
I don't agree. I wouldn't trust a crimped 2.5mm^2 connection rated to carry 20A made with the cheapo tool.
You can join them. Neatest solution is a dedicated enclosure with say DIN rail terminals. However junction boxes are fine if you are not planning on plastering over them. There are also plenty of other enclosures you can use with wago terminals or crimps etc.
As I read the original post we are talking about household ring cables rather than tails or anything else carrying particularly high currents. These are jointed all over the place. Unless they are going to be inaccessible surely junction boxes would suffice. Also gives a means of disconnecting individual circuits if this is ever required.
Having just "done" my first wagobox (2 way light circuit with incoming power and the light at the same end, so four cables into the box), I must say I am very impressed with them. They do a nice mini-pack with four boxes and an assortment of connections which is a handy and reasonably priced "taster". For the case described, you could use a pair of 773-173's to take the two ends of each ring main (2.5 solid) and connect to 6 mm^2 "conduit" wire to go into the CU, making a relatively neat and un-cluttered layout. Easier to to than crimping, if tails are short or space is otherwise tight.
Agreed, the DIN rail is neat and looks very professional: might be the option if you wanted to tidy up an old installation prior to selling, but it's not cheap.
The meter tails are fine. They will reach easily to the new location.
I'm just doing my garage electrics. Standard metal adaptable box:
Din rail:
Assorted WAGO connectors.
3 wires in, 3 out, total cost less than £10 per box. This size of box will take probably 12 WAGO 2.5mm connectors, which cost 45p ish each, so not at all expensive for what would be a nice neat job.Maybe £20 for a similar set-up for a fusebox to consumer unit conversion?
Alan.
I wouldn't be that keen myself. However I wouldn't trust a pre- insulated crimp made with either tool.
The problem is that the insulator around a pre-insulated crimp is relatively soft and thick, which affects the ability of either tool to make an accurate crimp inside it. Crimps rely on an accurately shaped jaw to displace the connector in the right shape. Wrapping this up in something squishy makes for unreliable crimps, no matter which tool you apply to the outsides.
How did you fix the DIN rail to the box?
Either screw straight through the din rail and box into backboard, or pan head screw and nut.
OK
Personally I would not crimp solid conductors. To produce a correct cold weld involves several critical success factors; a crimp tool of the right type (single indent for fine stranded, circumferential impingement for stranded/solid); precise force applied consistently; correct crimp design for the conductor type (solid, stranded, fine stranded); crimp maker matched to tool maker (often forgotten).
Personally I would never solder. Most people can learn to solder with even a little practice (avoid a dry joint), and learn to bind two solid conductors together with fine copper wire so the solder does not take the current & fault current, and learn to adhesive heatshrink (preferably in the appropriate colours). However for extending a CU it is a bit messy.
I would always use DIN rail terminal block in a suitable enclosure. The CU uses such terminals, they are easy to access, inspect, maintain, alter, extend, reduce. Just bundle appropriate cables at entry to the enclosure with P-clips sized to hold the cables tight (so no load can be imposed on terminals), or route cables in trunking, etc.
You can get DIN rail terminals & enclosure from Ebay, CPC, Farnell, RS, Rapid, electrical factors, lots of places online. The box may cost about =A38, the DIN terminals and end-blocks will cost probably =A315-20 depending on number. If in doubt, post the circuits and it only takes someone a few minutes to suggest the part numbers required.
A novice might screw-up crimping or soldering, and right by a CU it is a cascading fire, whereas the probability of copying the photo with screw terminals is both safer and easier - it allows adjustment in future. Soldering & crimping does not (you end up running short of cable with changes, something a DIN terminal will prevent).
Compared to the excellent web stuff on the "loose" connectors used in the Wagobox, they don't make a very good job of explaining the capability of their rail mounted terminals, though. It looks as though the push-fits only take two wires, is that right? Do you have to use a lever clamp if you want to put two or more wires in one entry?
And as you point out, a TLC box and rail is much cheaper than the Wago one (although I think I would be inclined to use a plastic box). I have a CU to replace some time, and I'd like to make it look tidy compared to the rats nest that I inherited.....
I've only used a metal box as I had to terminate some SWA cable. Yes, you can only fit 2 wires in each of the DIN mount terminals, though the normal terminals are available in up to 5 ways iirc, and a DIN rail mount can be bought for these too, though they are not as tidy looking:
HTH Alan.
I'll probably go the DIN rail terminal route. I have a Hager enclosure for 8 modules (?) that I was going to use for a garage unit.
The circuits are:
6 mm^24 mm^2
Ring 2 x 2.5 mm^2
Lighting 2 x 1.5 (?) mm^2
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