Practical question on crimping spur off 4mm T&E

[lonw2x]

Might be an obvious one but I want to confirm the right way ... how to crimp a spur off a 4mm T&E? With 3x4mm cables, yellow insulated for the earths, and 10mm uninsulated for L+N? Is it best to feed all three in one end, or two in one end, and third in the other?

 

[Spark123]

Use an accessable accessory to feed the spur from, don't use crimps.

 

[lonw2x]

Is buried under plaster and will be inaccessible ... this is best of the options, nothing wrong with crimps if done properly as far as I know

 

[Spark123]

Crimps are not made to have more than one wire in each terminal.

 

[lonw2x]

So have to solder then?

 

[Spark123]

Soldering is one option however as far a DIYing it is concerned I'd still recommend running the cable to an accessible accessory.

 

[lonw2x]

Thought about that but stuck because running to an accessory still means breaking and extending with crimps and adds 5m to circuit length (radial) which can push over volt drop on last socket.

 

[ericmark]

There is a brass crimp that can be used but they require a hydrolic crimping tool and is not DIY. Seem to remember something like 10 tons of pressure.

I have used them on petro-chemical sites where a 16mm earth cable was laid on the tray and a 6mm tail crimped on at every joint to earth tray.

Never ever seen one used in a domestic wiring.

 

[lonw2x]

Decided I am going to solder it - soldered a lot of electronics over the years, but not 4mm T&E ... will do a couple of practice runs first.

 

[RF Lighting]

Sounds like a lash up to me.

Never in all my years in the trade have I needed to do what you propose.

 

[lonw2x]

What would you do?

 

[RF Lighting]

Make the joint in an accesory.

What happens if your joint ever fails?

 

[lonw2x]

If really needed, can dig through plaster to access the box. Not trying to be smart or nothing, but regs allow crimps and solder for inaccessible joints if done proper and tested. Cable runs along top of wall and putting a socket in on other side of wall and no close accessory I can take off from.

 

[RF Lighting]

The easiest way isn't always the best way.

I bet I could find a better way of wiring your socket that doesn't require an inaccesible joint.

 

[Taylortwocities]

Thought about that but stuck because running to an accessory still means breaking and extending with crimps and adds 5m to circuit length (radial) which can push over volt drop on last socket.

I'm going to challenge you on that. You must have quite a load to push yourself over the vd threshold on a 4mm² conductor by just adding 5 metres of cable!