wiring question

[123hotchef]

Ok we have just dropped my mates kitchen and dinning room ceiling and now raised the height by 2"

I now need re route all of the cables coming from the CU and will need to add a section of wire to each to lengthen them.

Plan is to cut them and use the insulated crimp butt connectors can anyone see a problem with this of come up with a better way of doing it.

I don't want to use chock blocks or terminal boxes as they are too big I also thought of using the wago lever type connectors but they will take up more space and not be as neat.

There are masses of wires to extend 2 CU worth for a big 4 bedroom house and these cables will be hidden above the new ceiling.

I hope I didn't miss anything

Lee

 

[brightspark]

get a decent size plastic enclosure drill 20mm holes along it in and out. feed the cables in and crimp the joints. u haven't said what's above the ceiling is it attic space or a room above that is accessible

 

[WorkshopChris]

How far from board? is there any chance you can run new form board back to a point rather than drop a short length in. That's half the crimps. they will always be the weakest link. Use the best quality crip you can afford ideally with a quality plating and serrations, then heat shrink each one the over the whole cable. (a few cheap crimps are not made with self extinguishing plastic) Providing you have space cut each core a few inches longer that the next to stagger the crimps then you have a slim cable rather than a lump in one spot.

 

[123hotchef]

above the ceiling is a block and beam concrete floor for the bedrooms above so no chance of access from above once the new ceiling is in place

its too far and too much hastle to go back to the consumer units tbh becase that would mean dropping another ceiling in the utility room to find and unclip all the wires.

I would need more than 1 plastic enclosure I think to get all of these wires in as it is the main cable run for the house must be about 20 circuits

What would be deamed a good quality crimp @WorkshopChris I know the ones I use from beal ect for automotive circuits are not they are just steel tubes with plastic insulation one the top. Although I have seen them used in plenty of houses over the years.

 

[500e]

3M
They do them with heat shrink insulator

 

[Wendelspanswick]

I bought some heat shrink solder crimp terminals recently, I haven't tried one yet but it seems to have a low temperature solder that is melted by the heat used to shrink the insulation.

 

[123hotchef]

yes I have used the solder heat shrink ones in the past they are better suited to multi strand cables IMO

 

[Wendelspanswick]

 

[123hotchef]

yep same as the ones I have in varying diameters and colours for different thickness wire

 

[Robotstar5]

You can get butt crimp connectors with heat shrink built in - link

 

[123hotchef]

You can get butt crimp connectors with heat shrink built in - link

yes i know i use beal for all my leccie bits

https://www.beal.org.uk/electrical-products/heatshrink-terminals.html

 

[brightspark]

I use swa make connectors . no need for shrink fit as there in an enclosure and internal. use decent set of ratchet crimps . screwfix ect sell crimp barrel conectors and there crap so don't buy anything that's unbranded http://www.electricbase.co.uk/butt-connectors-1461-0000use 2 plastic enclosures if theres a lot of wires no need to bunch them up easier to work on and keep the wires in line and neat .make a note of where the boxes are above the ceiling in case u ever need to cut open for acess

 

[Robotstar5]

+1 for using decent ratchet crimpers, I find facom crimpers easy to use. I hate coming across crimps done with a pair of sidecutters

 

[dobbslc]

I'm not a fan of the normal blue red yellow crimps myself, I just don't trust them. I reckon the Wago type boxes are the way to go. Any kind of screw terminal will need to be "accessible for inspection" so no good for you in this case.
If you use those solder joints you'll still need to cover them with an enclosure to protect the cable inner cores as you will have stripped back the outer sheathing.

 

[dobbslc]

I recently found a 300mm main earthing cable "crimped" with what looked like a hammer and bolster! It was on a 800 amp supply and yes it did wobbble a bit....

 

[WorkshopChris]

What would be deamed a good quality crimp @WorkshopChris I know the ones I use from beal ect for automotive circuits are not they are just steel tubes with plastic insulation one the top. Although I have seen them used in plenty of houses over the years.

Its down to personal preference, but i personally consider this a high risk situation i would be looking for something with a UL approval and specifications There are to many unknowns out there.
This type of thing would be at the top of the list http://uk.rs-online.com/web/p/crimp-butt-splice-terminals/5289264/
then you have this

You can get butt crimp connectors with heat shrink built in - link

Even the own brand RS Pro have approvals.
In the event of a future problem the last thing you need is mr fire officer telling the insurance company i looks like a fire started in a loose or corroded crimp joint in the roof space, and they use that as a get out of paying the claim.

Dont get me wrong i have used generic crimps from all sorts of companies, but this just isn't the place you want even a minor problem.

 

[123hotchef]

I may need 4 boxes 2 each end

are the boxes a must?

If I didnt use boxes I could stager the joints and they would just be about the ceiling

I dont want to use the wago style ones because they wont be as neat on this job more cuber-sum than anything I think

 

[brightspark]

use chock boxes and crimp the cables and spread them about if not in a couple of enclosures

 

[123hotchef]

I do like the enclosure idea it would make it easier to find them later in the event of a problem

 

[Seadog]

Uninsulated straight crimp connectore, then solder and heat shrink. If you can find them that is.