SWA For meter tails?

[Msitekkie]

I need to upgrade my meter tails to 25mm. The existing tails pass along under the pebble dash in plastic conduit (which would be too small), then apparently at an angle through the porch structure (unprotected) then turn sideways into a void & up the void to CU.

I have seen other posts where the use of SWA is suggested but I haven't actually seen SWA with 25mm cores. "25mm SWA" appears to be 25mm "Outside diameter", so I presume that means the cores are smaller.

Any suggestions as to the best approach welcomed. I actually think I will struggle with getting SWA through anyway even if it does exist with suitable cores, because of the bends involved.

NB The meter box is under the window of the house rather than on the side of the porch, but the void inside the porch is set back behind the run of the outside wall so it's not possible to drill directly through the outside porch wall into it.

 

[MJPD29]

You can get 3x25mm swa ordered at the majority of wholealers

 

[Taylortwocities]

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?

 

[Spoon]

You can get 25mm SWA cable, and bigger.
Remember that if the tails are longer than 3 meters then you need to fit a fused isolator.

 

[Pete999]

I need to upgrade my meter tails to 25mm. The existing tails pass along under the pebble dash in plastic conduit (which would be too small), then apparently at an angle through the porch structure (unprotected) then turn sideways into a void & up the void to CU.

I have seen other posts where the use of SWA is suggested but I haven't actually seen SWA with 25mm cores. "25mm SWA" appears to be 25mm "Outside diameter", so I presume that means the cores are smaller.

Any suggestions as to the best approach welcomed. I actually think I will struggle with getting SWA through anyway even if it does exist with suitable cores, because of the bends involved.

NB The meter box is under the window of the house rather than on the side of the porch, but the void inside the porch is set back behind the run of the outside wall so it's not possible to drill directly through the outside porch wall into it.

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

 

[The Ghost]

Surely that is a job for the DNO?

 

[Taylortwocities]

Surely that is a job for the DNO?

Isn't he (I hope) talking about the run from the meter to the consumer unit?
@Msitekkie can you clarify all our questions above please?

 

[Midwest]

So many questions, and so few answers

 

[Spoon]

I bet anyone (a cheese cake) that the OP is talking about the cables from the meter to his CU....

 

[The Ghost]

So he WILL break the seals then?

 

[westward10]

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

 

[Pete999]

I bet anyone (a cheese cake) that the OP is talking about the cables from the meter to his CU....

Trouble is Spoon he aint talking much, been quite for a couple of hours.

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

Don't think the OP has factored that in. Offline as we speak.

 

[Rpa07]

We can talk amongst ourselves whilst we are waiting - let’s face it, we normally do!
Agreed it’s meter to CU. The Lord help him when he gets back to all the questions!

 

[Spoon]

We can talk amongst ourselves whilst we are waiting - let’s face it, we normally do!
Agreed it’s meter to CU. The Lord help him when he gets back to all the questions!

No one talks to me, so I have to come on here.... OK, hardly anyone talks to me on here as well....

 

[Taylortwocities]

Has anybody heard anything from Spoon lately?

 

[Rpa07]

‘A voice in the wilderness’
- @Spoon you get PMs from your ‘special’ friend @SWD so don’t go playing that tiny violin anywhere near us!

 

[Spoon]

‘A voice in the wilderness’
- @Spoon you get PMs from your ‘special’ friend @SWD so don’t go playing that tiny violin anywhere near us!

But I have to pay him to talk to me....
and he didn't even send me a PM.....

 

[Rpa07]

It still counts, no one thinks less of you (well, less than they do now anyway!)

But I have to pay him to talk to me....
and he didn't even send me a PM.....

 

[Rpa07]

I think there may have been too many megabytes to send what he intended across the t’internet! Eeewh!

But I have to pay him to talk to me....
and he didn't even send me a PM.....

 

[Spoon]

I think there may have been too many megabytes to send what he intended across the t’internet! Eeewh!

If he's sending d*ck pics then the pics would be very small...

 

[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?

 

[Risteard]

As above the OP seems wholly incompetent to carry out this work. He needs an Electrician.

 

[Pete999]

Agree with the above posts, do yourself a favour and employ an Electrician to sort your problem out.

 

[Msitekkie]

Give a guy a break. If you looked at my profile you would see I'm a qualified electrician but still very new to the trade. I thought this forum was here to help people like me who are still learning, rather than knock us down. If people can't be open and ask questions that might show they are inexperienced then it rather limits the usefulness of such forums. I'm already aware I lack practical experience and have been trying to find someone with more experience I can work with as an Electricians Mate to remedy that. In the meantime I turn to you guys... As it happens I probably am going to involve someone with more experience on this one, as no answers from anyone on the routing question, although I appreciate that's difficult to visualise on a forum such as this.
CSA may be obvious when you have been in the industry for years, but when you see a listing for 25mm SWA that specifies 25mm OD and makes no reference to CSA/core size alongside, it does raise a question mark in one's mind.

 

[Pete999]

Give a guy a break. If you looked at my profile you would see I'm a qualified electrician but still very new to the trade. I thought this forum was here to help people like me who are still learning, rather than knock us down. If people can't be open and ask questions that might show they are inexperienced then it rather limits the usefulness of such forums. I'm already aware I lack practical experience and have been trying to find someone with more experience I can work with as an Electricians Mate to remedy that. In the meantime I turn to you guys... As it happens I probably am going to involve someone with more experience on this one, as no answers from anyone on the routing question, although I appreciate that's difficult to visualise on a forum such as this.
CSA may be obvious when you have been in the industry for years, but when you see a listing for 25mm SWA that specifies 25mm OD and makes no reference to CSA/core size alongside, it does raise a question mark in one's mind.

Not in an Electrician's mind it doesn't, just checked your profile, those qualifications you have, are designed for practising Electricians, designed to update their knowledge. These courses do not make you an Electrician, if you were told that by the Training Schools then you have been duped.

 

[Andy78]

I've looked at your profile. There is nothing in there that indicates you are qualified in any meaningful sense as an electrician.

CSA is obvious to those that have been in the trade for ages, and also those new to the industry who have done proper training.

 

[Spoon]

Don't take offence @Msitekkie . By most of the opinions on here I'm neither an 'electrician' or 'engineer'.... Everyone to their own....

 

[Pete999]

Don't take offence @Msitekkie . By most of the opinions on here I'm neither an 'electrician' or 'engineer'.... Everyone to their own....

Deleted

 

[LeeH]

I was just waiting for somebody to blow up on this thread....and DS was the first.

 

[Msitekkie]

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?

House+garage+workshop:
Starting with 7.4Kw Induction Hob (1st 10A plus 30% of the remainder) 16.6A already...
3Kw Immersion heater - No Diversity allowed another 13A...
3Ring + 3 Radial Circuits (100% of 1st & 40% of rest) 32+49.6 = 81.6A
+ 4 x 6A lighting - haven't worked out all the lights I'm having yet, so lighting diversity still up in the air (although mostly a mix of compact flourescents & LEDs).
I know diversity is a bit of a black art so any constructive comments/suggestions welcomed. As the immersion is only used in emergencies if CH not working. I'm wondering if there are any options there.
P.S I don't have a clamp meter yet.

 

[Andy78]

Don't take offence @Msitekkie . By most of the opinions on here I'm neither an 'electrician' or 'engineer'.... Everyone to their own....

He was the one that brought up qualification defining his status in fairness