4 core swa feeding ring

sibbits · Feb 27, 2014

just wondering what other people think of wiring leg out to a ring in a single swa 4core 2.5 using the armoring as the earth?
its about 10 mtrs from the board and wouldnt have massive loading on the end.
i know that using 2 seperate pieces is best but i have a piece of 4 core long enough and am thinking bout using it .

uksparks · Feb 27, 2014

Archy Styrigg said:
What would you do with an RFC with metallic containment as the CPC?

You would only be able to get an R2 reading as its not a ring. I am aware of this, its just the person was looking at extending both legs but just using one conductor / armouring for CPC instead of having two that's all.

Knobhead · Feb 27, 2014

4 core SWA amour = 20mm² whereas the minimum requirement is 5.7mm² (single circuit) for steel wire.

Where’s the problem if the SWA is terminated properly?

Knobhead · Feb 27, 2014

uksparks said:
I was just thinking, if you use this, how are you going to get your r2 ring value? as it will be one piece at the SWA...

How would you test a lollipop ring? The proposed set up isn’t out of the ordinary for experienced electricians.

Darkwood · Feb 27, 2014

Tony said:
4 core SWA amour = 20mm² whereas the minimum requirement is 5.7mm² (single circuit) for steel wire.

Where’s the problem if the SWA is terminated properly?

Spoiling my fun Tony

- trying to get him to think like an Electrician if he checked it he'd realise it was well within tolerances with spare.. but being told yes its ok won't get him to realise why its ok... but as he never counted my post with yes it works out fine i assume he didn't bother checking.

Ive stopped giving out straight answers now im getting the OP's to contribute to solving their issues more and understand the calcs behind it as it seems less and less now bother with them as scary as it sounds.

Silly Sausage · Feb 27, 2014

darkwood said:
Ive stopped giving out straight answers now im getting the OP's to contribute to solving their issues more and understand the problem better and hopefully never forget

I stopped dishing it out a long time back, just give hints or another question.
Make the buggers think!

Sintra · Feb 27, 2014

As long as the SWA isn't terminated like this abortion lol

uksparks · Feb 27, 2014

Tony said:
How would you test a lollipop ring? The proposed set up isn’t out of the ordinary for experienced electricians.

I accept what you are saying, but what I'm saying is, if he is to extend the ring in this fashion but the cpc being a lollipop where as the legs are not, going back to the distribution board for the ring that's being extended you get your readings for r1 and rn as it's a "ring" but for r2, it's not a ring... It's two rings with essentially and interconnection is it not?

not only that the r2 reading will not be what you would expect for a 2.5mm being 1.67 times higher roughly speaking.

the only thing that I can think you would need to do is disconnect the armouring, get the r2 of the first ring, then get the r2 of the second ring then measure the resistance of the armouring.

Can someone clearly explain you intend to get the r2 ring value please on what is a lollipop circuit where the cpc is concerned. Sorry if this is glaringly obvious, just not one I have contended with before.

GLENNSPARK · Feb 27, 2014

Archy Styrigg said:
If this is domestic, I wonder how he's going to terminate the ends?

jubilee clips...

netblindpaul · Feb 27, 2014

darkwood said:
Spoiling my fun Tony - trying to get him to think like an Electrician if he checked it he'd realise it was well within tolerances with spare.. but being told yes its ok won't get him to realise why its ok... but as he never counted my post with yes it works out fine i assume he didn't bother checking.

Ive stopped giving out straight answers now im getting the OP's to contribute to solving their issues more and understand the calcs behind it as it seems less and less now bother with them as scary as it sounds.

It seems I get slated for the same methods, mind I am somewhat blunt in my approach!

- - - Updated - - -

Archy Styrigg said:
I stopped dishing it out a long time back, just give hints or another question.
Make the buggers think!

Please see quoted reply to DW above!

micknew · Feb 27, 2014

GLENNSPARK said:
jubilee clips...

Your such a perfectionist Glenn.

Silly Sausage · Feb 27, 2014

GLENNSPARK said:
jubilee clips...

For goodness sake!
I use them for TNS Earth clamps on old cables, non of that 951 nonsense.

sibbits · Feb 28, 2014

ooh .....this ones caused quite stir overnight
it always makes me laugh how the "pub members"always :
A)think the op is a Electrical Trainee
B) think that its a diy-er

[ElectriciansForums.net] 4 core swa feeding ring

ive got the tables that say its 20mm, but it doesnt seem good practice
the sockets at the end would be "through wired" and im pretty sure thats rough
so,as i said ill save the cable for a motor or somthing else.

Engineer54 · Feb 28, 2014

sibbits said:
ooh .....this ones caused quite stir overnight
it always makes me laugh how the "pub members"always :
A)think the op is a Electrical Trainee
B) think that its a diy-er

View attachment 23339 ive got the tables that say its 20mm, but it doesnt seem good practice
the sockets at the end would be "through wired" and im pretty sure thats rough
so,as i said ill save the cable for a motor or somthing else.