Advice From A Sparks

[Wendelspanswick]

I am after some advice from a Sparky, I want to add some sockets into the ring circuit in my workshop. The current wiring is in 4mm singles in steel conduit and square containment, fed from a 32amp cartridge fuse. Where I want to add my sockets I am going to have to cut into the existing ring (it is going to be awkward to draw in the new singles back to an existing outlet). The joint will be in the square containment.
My question is can I use yellow crimp connectors with the proper ratchet crimp tool to splice the 4mm together or do I have to use terminal blocks (which I loathe).
Cheers in advance.

 

[Robotstar5]

Yes, butt connectors are a much better mechanical connection than "choccy blocks"

 

[MCKDAVID]

^^ not sure about that, I though crimped connections were only for stranded wire, not solid core?? besides which the yellow is for 6mm² CSA not 4mm²

not sure you'd get a good connection with the solid, but over to the more knowledgable people....

 

[wheresmejumper]

I am after some advice from a Sparky, I want to add some sockets into the ring circuit in my workshop. The current wiring is in 4mm singles in steel conduit and square containment, fed from a 32amp cartridge fuse. Where I want to add my sockets I am going to have to cut into the existing ring (it is going to be awkward to draw in the new singles back to an existing outlet). The joint will be in the square containment.
My question is can I use yellow crimp connectors with the proper ratchet crimp tool to splice the 4mm together or do I have to use terminal blocks (which I loathe).
Cheers in advance.

no matter how awkward or time consuming,it is by far the best method.
if its possible,i wouldnt do it any other way

 

[madkayaker]

yellow crimps are just fine. depending on the make of blue they sometimes fit 4mm but not always.

these are even better thoughhttp://www.screwfix.com/c/electrical-lighting/wago-cable-connectors/cat5260002


might be worth considering the RCD question while your at the job as well.


MCKDAVID "singles" haven't been a single conductor for 30 years + but 7 strand multi conductor

 

[Wendelspanswick]

Thanks for that, yes it's multi-strand conduit cable that I am using.
The existing sockets get there CPC from the steel conduit, if I use plastic conduit can I run a CPC from the socket through the plastic conduit into the steel containment where I can crimp on a ring crimp and bolt to the side of the containment?

 

[madkayaker]

you can but it would be better to take the CPC from the fuse box.

 

[the snooper]

why not just fit a socket at the point you intend to cut the cable and have an extra couple of sockets as the joints

 

[Robotstar5]

Was going to suggest Wago or Line connectors, but they're not as cheap as crimp connectors. All 3 types are classed as maintenance free unlike choccy blocks which are required to be accessible.

Edit: crimp connectors fitted with "proper" crimpers are acceptable on solid core cable.

 

[MCKDAVID]

madkayaker, Singles - I stand corrected then, been away from the uk a long time, certainly 4mm² singles and 3G4mm² etc here are solid core....you only get into dtranded above 6mm, (for domestic wiring anyway) no matter, as for the OP, then obviously crimps are fine.

robotstar, As for crimping solid core, there's arguments for and against, for stranded no debate, but personally with the small crimps, & solid core I don't think you get the same level of compression / contact surface area that you get with stranded, so I would't do it, as I think vibration and corrosion will eventually become an issue, but if you're happy then go ahead..

 

[skotl]

Any connections into the line needs to be easily accessible and maintainable. See http://electrical.theiet.org/wiring-matters/42/junction-boxes.cfm?type=pdf for more information.

If you want to extend a ring then the best bet is to, err, extend the ring. Start at an existing socket and wire in the new loop, and end the new loop back at the next socket.

I can't suggest that this is a safe solution because every installation is different, but it's probably the most likely solution that will satisfy regulations.
Ideally, present the requirement to your electrician and have them design, install and certify the result.

You can get more advice (and abuse) at http://www.diynot.com/forums/viewforum.php?f=8

 

[Wendelspanswick]

The reason I need to cut into the ring rather than extend it from the adjacent socket is that the conduit from the adjacent socket enters the square containment under the roof. The roof has been changed since the installation meaning I cannot lift the lid on this section without major hassles.
This is why I was asking about the suitability of using crimps!
Thanks for the helpful advice. Job done now.