SWA For meter tails?

[littlespark]

Someone sending pics of ducks?

 

[Spoon]

Someone sending pics of ducks?

yep, very small ones..

 

[littlespark]

Here's a pic of a huge d*ck

 

[7029 dave]

Meter tails SWA?, are running a sub to the CU.?That makes more sense.

 

[Msitekkie]

Sorry for the slow reply to everyone. Been out for my daughters birthday. To answer some of the questions the DNO is due to come to upgrade my main fuse to 100A (extension project including an induction hob) so the tails to the CU need upgrading 1st. Did diversity calcs and I'm struggling to get it down to 100A actually.
I did have a DP isolator switch fitted by my provider in anticipation, so no seals being broken, but I'm not sure that it's fused...
I'm hoping it's less than 3m, but it's fairly close, so need to measure again when I know how I'm routing the cable.

 

[Msitekkie]

I wonder how the cable conductors will be enclosed or the cable glanded for that matter.

Yes I was wondering about cable enclosure if I don't use SWA. Seemingly 25mm Conduit can be used, according to the cable factors.
16mm factor = 145
25mm Cable factor = 217 2x217 = 434
Total = 589
But I can't quite see how two 25mm cables fit in a 25mm pipe? Maybe something about the size of the cable I'm missing as I don't actually have any 25mm tails.

 

[Ian1981]

Sorry for the slow reply to everyone. Been out for my daughters birthday. To answer some of the questions the DNO is due to come to upgrade my main fuse to 100A (extension project including an induction hob) so the tails to the CU need upgrading 1st. Did diversity calcs and I'm struggling to get it down to 100A actually.
I did have a DP isolator switch fitted by my provider in anticipation, so no seals being broken, but I'm not sure that it's fused...
I'm hoping it's less than 3m, but it's fairly close, so need to measure again when I know how I'm routing the cable.

The DNO May allow 5 meters
My local DNO really don’t care when you ask them about max length of tails they will allow , protected by their fuse.
Very helpful!

 

[Ian1981]

Yes I was wondering about cable enclosure if I don't use SWA. Seemingly 25mm Conduit can be used, according to the cable factors.
16mm factor = 145
25mm Cable factor = 217 2x217 = 434
Total = 589
But I can't quite see how two 25mm cables fit in a 25mm pipe? Maybe something about the size of the cable I'm missing as I don't actually have any 25mm tails.

Don’t forget the earthing conductor

 

[Msitekkie]

Why do the tails need rewiring? What is the Earthing system?

My main fuse is due to be upgraded to 100A due to an extension project that involves an induction hob. Actually with my diversity calcs, I'm struggling to get it down to 100...

 

[Msitekkie]

What is the Earthing system?

TN-CS

 

[Msitekkie]

So he WILL break the seals then?

No seals being broken. I had an isolator fitted by my provider in anticipation, I'm not aware of it being fused however.

 

[Msitekkie]

Surely that is a job for the DNO?

DNO replace the fuse, but they won't do the tails to the CU.

 

[Msitekkie]

25mm SWA is common stuff for example
25.0mm² 6943X 3 core SWA Steel Armoured Cable

You will have some challenges with bend radius. I assume that you will (have already) a switch/fuse at the cut out end? Due to the length of the tails?

PS Why do you feel that an upgrade to 25mm is needed?

Thanks for the link. That's the cable I looked at first, but doesn't OD stand for outside diameter? How can that be 25mm if the individual cores are 25mm?

 

[Pete999]

Don’t forget the earthing conductor

Yes I was wondering about cable enclosure if I don't use SWA. Seemingly 25mm Conduit can be used, according to the cable factors.
16mm factor = 145
25mm Cable factor = 217 2x217 = 434
Total = 589
But I can't quite see how two 25mm cables fit in a 25mm pipe? Maybe something about the size of the cable I'm missing as I don't actually have any 25mm tails.

The cable are reffering to 25mm2 csa, not diameter

 

[Jim_e_Jib]

Thanks for the link. That's the cable I looked at first, but doesn't OD stand for outside diameter? How can that be 25mm if the individual cores are 25mm?

It does but as Pete999 says, the reference is to 25mm2 CSA SWA. It looks to be a happy coincidence of maths, manufacturing and electrical requirements that this 25mm2 SWA has a nominal OD of 25.1mm

 

[Pete999]

Don’t forget the earthing conductor

Yes I was wondering about cable enclosure if I don't use SWA. Seemingly 25mm Conduit can be used, according to the cable factors.
16mm factor = 145
25mm Cable factor = 217 2x217 = 434
Total = 589
But I can't quite see how two 25mm cables fit in a 25mm pipe? Maybe something about the size of the cable I'm missing as I don't actually have any 25mm tails.

The cable are reffering to 25mm2 csa, not diameter

 

[telectrix]

if he's got to fit switch fuse, he might be better off dropping to 80A SW/F and then using 16.0mm SWA. easier to install.

 

[Msitekkie]

It does but as Pete999 says, the reference is to 25mm2 CSA SWA. It looks to be a happy coincidence of maths, manufacturing and electrical requirements that this 25mm2 SWA has a nominal OD of 25.1mm

Some lights going on... That's really helpful thanks.
Led me to this CSA to diameter calculator page which may help someone else:
Cross-sectional area to diameter conversion circle intersection cross section diameter electric cable conductor formula wire diameter and wiring and calculation cross section AGW American Wire Gauge thick area of a solid wire formula conductivity resistivity stranded wire litz length current - sengpielaudio Sengpiel Berlin - http://www.sengpielaudio.com/calculator-cross-section.htm

 

[Msitekkie]

if he's got to fit switch fuse, he might be better off dropping to 80A SW/F and then using 16.0mm SWA. easier to install.

Not an option given I'm struggling to get diversity calcs down to 100A and I already have 16mm tails anyway.

 

[davesparks]

Not an option given I'm struggling to get diversity calcs down to 100A and I already have 16mm tails anyway.

You’re probably getting the calculations wrong then, the average house doesn’t need much more than about 20A.

Out of interest how did you arrive at a figure over 100A for a house?


Not knowing that conductors sizes are measured in CSA or that SWA is made in 25sqmm (and much bigger) and suggesting that 25mm tails could be installed in 25mm conduit show that you aren’t an electrician so why not employ one to do the job correctly and safely?