what box to terminate SWA cable

[NeoCool]

Hi I have a question that im pondering on for a few days now.
I have run 6mm SWA 3 core from my house to my new workshop. Single Phase
It comes from underground 600mm laid in sand 150mm then soft ground then hard.

It comes from under my workshop and up into the workshop floor up from the corner.

I have my garage consumer unit and my questins are about the regulation requirement.
Im guessing i cant install my consumer unit right in the corner with the SWA coming up from underneath it.

So thinking of putting my consumer unit 300mm in from the corner, but to avoid a big bend in the SWA before it goes to the consumer unit, im thinking about keeping it straight up and terminating into a box.
Before it then goes by a bit of conduit accross into the consumer unit enterning if from the right.

Quesitons can I use a plastic box, or do i need to use a metal box to terminate the SWA Gland?
what do i do with the 3rd earth core if im using the swa as the termination in the box?
And what do you think of my above senario is it under regulation or not.

Any feed back greatfully recieved.

 

[Marvo]

SWA cable can be bent around any angle as long as the radius of the bend isn't too tight. You can terminate the SWA cable in either a plastic of metal box using an SWA gland and earth ring (banjo) and the third wire should also be earthed.

 

[NeoCool]

Thanks Marvo
So i can use plastic or metal cool, If plastic will it have a termination point inside to attach my crimped made up small earth wire to the banjo and to the box?
Im glad to hear I could keep the bend but it just looks awful. so the 3rd emendmant regualtion for metal boxes is only concerning Consumer Units then is that correct.?

 

[telectrix]

or use a metal CU to comply with latest regs. and gland the SWA into the CU direct.

 

[telectrix]

and who is going to test/certify it and notify building control?

 

[Marvo]

.......so the 3rd emendmant regualtion for metal boxes is only concerning Consumer Units then is that correct.?

As far as I know it is but wait for one of you fellow UK guys to confirm. As Tel suggests glanding direct into a steel CU would be the most elegant solution.

 

[NeoCool]

Thanks Telectrix. would do just my 6mm SWA comes up into the corner, and my consumer unit looks rubbish snug up to the corner of the wall, and I don't even know if thats allowed?
And the cable would have a big curve from the corner --- it crossed into the CU.? So thinking on a putting the SWA into a box, Then using the same size twin and earth 6mm in a bit of plastic conduit with plastic grommits glans int the CU.
does that all sound ok and within regualtion guys.?

 

[Marvo]

.....does that all sound ok and within regualtion guys.?

I'm guessing from Tel's last comment that this work would legally require notifying.

Depending on the earthing arrangement in the main house there's also possible issues that might require a separate earth spike / bonding for the outbuilding so I'd strongly suggest you get a sparky in to survey the job and arrange with him for you do the donkey work of installing the cabling under his guidance and he make the final connections and do the tests and paperwork.

 

[NeoCool]

Thanks guys will do. thanks for your feedback

 

[Octopus]

Thanks guys will do. thanks for your feedback

Well done for deliberately ignoring legal requirements. Best you don't come back!

 

[NeoCool]

Murdoch, thanks for feedback, its all being undertaken, building control notified, im using it and my in house consumer unit as my first to jobs under joining a part p scheme provider. So will do the installation and test and inspect myself.
but just getting overall feedback from the experiance of this great forum..

 

[HandySparks]

...just my 6mm SWA comes up into the corner, and my consumer unit looks rubbish snug up to the corner of the wall, and I don't even know if thats allowed?

Why wouldn't it be, unless it seriously restricted access to the CU?

And the cable would have a big curve from the corner --- it crossed into the CU.?

So?

So thinking on a putting the SWA into a box, Then using the same size twin and earth 6mm in a bit of plastic conduit with plastic grommits glans int the CU.

I'd rather see a curved cable than an unnecessary enclosure with an unnecessary additional cable joint, especially as you'll be reducing the cpc to 2.5mm².

 

[ipf]

If your insistent on jointing in a separate box, why not do it in galv conduit and box....much neater. As regards this t+e carp in conduit.....just strip the swa back a couple of metres and avoid jointing.
Still better direct to CU, though.

 

[davesparks]

Thanks Telectrix. would do just my 6mm SWA comes up into the corner, and my consumer unit looks rubbish snug up to the corner of the wall, and I don't even know if thats allowed?
And the cable would have a big curve from the corner --- it crossed into the CU.? So thinking on a putting the SWA into a box, Then using the same size twin and earth 6mm in a bit of plastic conduit with plastic grommits glans int the CU.
does that all sound ok and within regualtion guys.?

6mm SWA and 6mm T&E are not equivalent cable sizes and types, to get a T&E which is equal to 6mm SWA in all respects you would probably need 16mm T&E.

Making off SWA in to a plastic enclosure is a poor substitute for a metal enclosure, assuming there is no requirement for a high IP rating (and even then there are some good metal enclosure options available)

Also introducing unnecessary joints in to a cable is just bad practice.

If you are going to be a qualified supervisor for a professional registration then you really should have a greater than average level of knowledge and experience.

 

[bigspark17]

I'm guessing from Tel's last comment that this work would legally require notifying.

Depending on the earthing arrangement in the main house there's also possible issues that might require a separate earth spike / bonding for the outbuilding so I'd strongly suggest you get a sparky in to survey the job and arrange with him for you do the donkey work of installing the cabling under his guidance and he make the final connections and do the tests and paperwork.

agreed. What is the earthing srrangement in the house? what is the fabric is the building made of.? Are there any extraneous conductive parts in the shed.?

 

[Octopus]

Murdoch, thanks for feedback, its all being undertaken, building control notified, im using it and my in house consumer unit as my first to jobs under joining a part p scheme provider. So will do the installation and test and inspect myself.
but just getting overall feedback from the experiance of this great forum..

OK.

So best you apply to join the trainee section and get your "diy member" changed.

Back to the OP - gland SWA into lower edge of AMD3 CU and run cores to appropriate connections in the unit.

As others have said adding unnecessary connections is not good practice.

What is at the house "end" of the SWA?

 

[Swcfisher]

You could use a whiska box with gland plate if you really want a plastic junction box

 

[Octopus]

I'm guessing i cant install my consumer unit right in the corner with the SWA coming up from underneath it.

Why not?

 

[tomspark93]

Sales as the others I'd either gland directly in to a metal consumer unit or if I had to (but I don't see the need here as its more work for no gain) gland to a metal box and run the inner cores through conduit to the cu, avoiding joints.