SWA current capacity

[EFLImpudence]

Each core when stripped of its insulation fits snuggly into a Yellow Lugg.

Yellow will take 6mm².

The measure the CSA of each 7 stranded core is approx. 3/16" / 4.5mm Each strand of copper wire is just less than 1mm.

CSA stands for Cross-Sectional Area.
Your figures do not match.

 

[JohnW2]

Your figures do not match. ....

That table of mine you've pasted in relates to T+E, and may not necessarily be the same for cores of SWA (although I can't see why not!). However, if the OP's 4.5mm core diameter included the insulation, his figures would be pretty close to 6mm² in that table.

However, as has been said, the questions the OP is asking strongly suggest that he really ought to involve an electrician in getting this supply (seemingly a 'new circuit', hence notifiable) to his cabin installed - for all sorts of reasons that I don't need to explain to you.

Kind Regards, John

 

[EFLImpudence]

That table of mine you've pasted in relates to T+E, and may not necessarily be the same for cores of SWA (although I can't see why not!).

Of course it's the same. Xmm² = Xmm² and Xmm²/7 = Xmm²/7

However, if the OP's 4.5mm core diameter included the insulation, his figures would be pretty close to 6mm² in that table.

Except for the <1mm² strand.

Each strand of copper wire is just less than 1mm.

However, as has been said, the questions the OP is asking strongly suggest that he really ought to involve an electrician in getting this supply (seemingly a 'new circuit', hence notifiable) to his cabin installed - for all sorts of reasons that I don't need to explain to you.

Of course, even Bas would agree with that.

 

[wiseingup]

yes i forgot to mention that the 4,5mm diam included the insulation! I do know what glands and how to terminate to terminate with. It is not a NEW installation but I am replacing an older cable with this much bigger and amoured cable,and updating the safety arrangements ie fixing an RCD etc. Earthing will be carried out at the main fuse box with the appropriate size earthing cable. If needed I can also fit an earthing rod into the ground at the cabin end. And NO the cable did not have any other marking on it, 2C 4.00mm or anything similar on it. 6mm is about right , i agree, so it will be ample for the current required.

 

[Iggifer]

what is the appropriate sized earthing cable?

 

[wiseingup]

thank you, but that is not the question i asked originally. Dont think this forum is an exam paper??

 

[Taylortwocities]

What size RCD should be installed to cover this.

Well, the RCD would be 30mA, I would expect. But did you mean RCD?

 

[JohnW2]

That table of mine you've pasted in relates to T+E, and may not necessarily be the same for cores of SWA (although I can't see why not!).

Of course it's the same. Xmm² = Xmm² and Xmm²/7 = Xmm²/7

It was the final of my columns (approx overall diameter) I was thinking/talking about, and that could differ a little between cable types according to how the strands were twisted.

However, if the OP's 4.5mm core diameter included the insulation, his figures would be pretty close to 6mm² in that table.

Except for the <1mm² strand.

I reckon that "less than 1mm" and "1.03mm" are in about the same ballpark, given measurement errors, particularly if what the OP measured was 'a bit squashed'!

Of course, even Bas would agree with that.

I'm sure he would - even though he doesn't agree with me all that often!

Kind Regards, John

 

[Iggifer]

thank you, but that is not the question i asked originally. Dont think this forum is an exam paper??

Clearly it's not an exam paper, but I was just expanding on your statement that you would use the 'appropriate sized earthing cable'

Your what size RCD question is also worrying, a perfectly correct answer could be 80A/30mA but as TTC has already pointed out, I don't think this is what you're asking.

Surely if you're replacing an existing cable, there will already be an MCB there, so there is no need to worry about the size of that?

 

[JohnW2]

Surely if you're replacing an existing cable, there will already be an MCB there, so there is no need to worry about the size of that?

... and if he did replace the MCB (with one having a different rating) as well as the cable, I think that would probably be sailing very close to the wind of a "new circuit", wouldn't it?

Kind Regards, John

 

[wiseingup]

Earth cable greater than =>10mm ok ? and no there is not an MCB there only a 30 a fuse at the fuse box. Old cable was laid prob. while you were still at school. No insult intended, but only to show that it is an old installation! And I am fitting a 30mA RCD consumer unit with MCB's for lights and power sockets as required by the new BS7671 2013 regs. Happy now?

 

[wiseingup]

and after its been installed i will get it inspected!

 

[JohnW2]

... Old cable was laid prob. while you were still at school.

I left school and headed off to uni in 1967 - it the cable really that old?

Kind Regards, John

 

[wiseingup]

If some of you Electricians did not charge so much , you would prob get an awful lot more work. Smaller profit = greater turnover? it worked for me for 20 odd years as self employed. Incidentally, in my lifetime I have been trained as a Mechanical technician, Armaments fitter, years ago I did the original ONC Electrical, later trained as an Electronics engineer working from early Valve Calculators to the latest main frame computers and then changed to Process Control instrumentation and Meteorological instrumentation. I only asked my original questions because I am too lazy now to look up the relevant Reg's and being on a fixed pension i can't always afford the rates being charged. I am quite capable of doing the work safely. Just wanted to make sure i got my figures right.

 

[wiseingup]

Cable etc was prob installed around mid 70's i think. LOL