Cable that looks like SWA but maybe isn't
 

I am trying to identify the cable that feeds our house consumer unit.
It was buried many years ago, before 1998 at least and quite likely
some years before that.

It's not a 'company' cable, the company fuse is outside, it used to
feed from an outdoor meter/company fuse, it now feeds (after a
re-route under the drive) from meter and company fuse in the garage.

It might be pre-metric SWA, the outside diameter is just over 23mm and
looks somewhat like black SWA. It's a three core cable with Red, Blue
and Yellow insulated cores.

I'd basically like to know what size it is if possible.

I'm not *absolutely* sure that it's armoured cable, was 'non armoured'
cable ever used?

--
Chris Green
·

Cable that looks like SWA but maybe isn't
 

On 28/07/2019 22:04, Chris Green wrote:
I am trying to identify the cable that feeds our house consumer unit.
It was buried many years ago, before 1998 at least and quite likely
some years before that.

It's not a 'company' cable, the company fuse is outside, it used to
feed from an outdoor meter/company fuse, it now feeds (after a
re-route under the drive) from meter and company fuse in the garage.

It might be pre-metric SWA, the outside diameter is just over 23mm and
looks somewhat like black SWA. It's a three core cable with Red, Blue
and Yellow insulated cores.

I'd basically like to know what size it is if possible.

I'm not *absolutely* sure that it's armoured cable, was 'non armoured'
cable ever used?

A magnet will tell you if it is armoured.

Cable that looks like SWA but maybe isn't
 

Chris Green formulated the question :
I'm not *absolutely* sure that it's armoured cable, was 'non armoured'
cable ever used?

It could be lead/paper, which should be plumbed at the end and sealed
in a compound box. It could be a tough PVC armoured cable without the
steel armouring.

Why not post a photo somewhere, to help identify it?

Cable that looks like SWA but maybe isn't
 

On Sunday, 28 July 2019 22:16:05 UTC+1, Chris Green wrote:
I am trying to identify the cable that feeds our house consumer unit.
It was buried many years ago, before 1998 at least and quite likely
some years before that.

It's not a 'company' cable, the company fuse is outside, it used to
feed from an outdoor meter/company fuse, it now feeds (after a
re-route under the drive) from meter and company fuse in the garage.

It might be pre-metric SWA, the outside diameter is just over 23mm and
looks somewhat like black SWA. It's a three core cable with Red, Blue
and Yellow insulated cores.

I'd basically like to know what size it is if possible.

I'm not *absolutely* sure that it's armoured cable, was 'non armoured'
cable ever used?

--
Chris Green
·

At one time "concentric" stranded cable was popular.
Centre core is live.
Outer ring is half earth and half neutral strands
Neutral strands individually insulated.

Looks just like SWA externally.
https://www2.theiet.org/forums/forum...threadid=62807

Cable that looks like SWA but maybe isn't
 

Harry Bloomfield, Esq. wrote:
Chris Green formulated the question :
I'm not *absolutely* sure that it's armoured cable, was 'non armoured'
cable ever used?

It could be lead/paper, which should be plumbed at the end and sealed
in a compound box. It could be a tough PVC armoured cable without the
steel armouring.

It's not lead/paper, the individual leads that enter the CU are fairly
normal looking PVC (I assume) insulated, Red, Blue, Yellow.

It certainly *could* be PVC only, that's sort of what I'd like to find
out. I'll try the magnet idea that someone else suggested.


Why not post a photo somewhere, to help identify it?

I'm not sure that that will help much, all you can see of the bit I
have exposed (in a dry lined wall which is about to be removed) is a
black plastic tube. I had originally thought it was a water pipe
because, wierdly, it has plastic foam insulation wrapped around it!
However all the plumbing is copper so I've decided the black plastic
thing must be the incomer.


--
Chris Green
·

Cable that looks like SWA but maybe isn't
 

newshound wrote:
On 28/07/2019 22:04, Chris Green wrote:
I am trying to identify the cable that feeds our house consumer unit.
It was buried many years ago, before 1998 at least and quite likely
some years before that.

It's not a 'company' cable, the company fuse is outside, it used to
feed from an outdoor meter/company fuse, it now feeds (after a
re-route under the drive) from meter and company fuse in the garage.

It might be pre-metric SWA, the outside diameter is just over 23mm and
looks somewhat like black SWA. It's a three core cable with Red, Blue
and Yellow insulated cores.

I'd basically like to know what size it is if possible.

I'm not *absolutely* sure that it's armoured cable, was 'non armoured'
cable ever used?

A magnet will tell you if it is armoured.

Absolutely right! Yes, it's SWA (well, a magnet sticks to it).

So, is it pre-metric then as the diameter doesn't seem to correspond
with the sizes given for metric SWA. It measures, as I said, about
23mm. 16sq mm would be about 21.5mm and 25sq mm about 25.5mm.

--
Chris Green
·

Cable that looks like SWA but maybe isn't
 

Chris Green wrote:
newshound wrote:
A magnet will tell you if it is armoured.

Absolutely right! Yes, it's SWA (well, a magnet sticks to it).

So, is it pre-metric then as the diameter doesn't seem to correspond
with the sizes given for metric SWA. It measures, as I said, about
23mm. 16sq mm would be about 21.5mm and 25sq mm about 25.5mm.

By the way, I need to know the size of the cable because I'm moving
the CU and will need to extend the incomer. I'll be crimping the
add-on so need to get the correct sized tube crimps (I have a
hydraulic crimp tool).

--
Chris Green
·

Cable that looks like SWA but maybe isn't
 

Chris Green wrote:

I need to know the size of the cable because I'm moving
the CU and will need to extend the incomer. I'll be crimping the
add-on so need to get the correct sized tube crimps

Sounds like the sort of job where for a few extra pence, you'd do well
to have the next sizes up and down on hand, just in case ...

Cable that looks like SWA but maybe isn't
 

Chris Green submitted this idea :
I'll be crimping the
add-on so need to get the correct sized tube crimps (I have a
hydraulic crimp tool).

What, you are adding an extra piece onto the existing bit?

Why not just get one piece long enough end to end, to avoid joints?

Cable that looks like SWA but maybe isn't
 

On 29/07/2019 08:27, harry wrote:
On Sunday, 28 July 2019 22:16:05 UTC+1, Chris Green wrote:
I am trying to identify the cable that feeds our house consumer unit.
It was buried many years ago, before 1998 at least and quite likely
some years before that.

It's not a 'company' cable, the company fuse is outside, it used to
feed from an outdoor meter/company fuse, it now feeds (after a
re-route under the drive) from meter and company fuse in the garage.

It might be pre-metric SWA, the outside diameter is just over 23mm and
looks somewhat like black SWA. It's a three core cable with Red, Blue
and Yellow insulated cores.

I'd basically like to know what size it is if possible.

I'm not *absolutely* sure that it's armoured cable, was 'non armoured'
cable ever used?

--
Chris Green
·

At one time "concentric" stranded cable was popular.
Centre core is live.
Outer ring is half earth and half neutral strands
Neutral strands individually insulated.

More commonly called "split concentric"


Looks just like SWA externally.
https://www2.theiet.org/forums/forum...threadid=62807



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Cable that looks like SWA but maybe isn't
 

On 28/07/2019 22:04, Chris Green wrote:
I am trying to identify the cable that feeds our house consumer unit.
It was buried many years ago, before 1998 at least and quite likely
some years before that.

It's not a 'company' cable, the company fuse is outside, it used to
feed from an outdoor meter/company fuse, it now feeds (after a
re-route under the drive) from meter and company fuse in the garage.

It might be pre-metric SWA, the outside diameter is just over 23mm and
looks somewhat like black SWA. It's a three core cable with Red, Blue
and Yellow insulated cores.


Depending on how much "just over" is, I would guess you either have:

From BS 6346:1997 "PVC Insulated armoured cables...", Table 9 Three
core 600/1000V cables with stranded conductors:

Nominal cross section 16mm^2, Approx overall diameter 23.1mm

Of from BS5467 1997 "XLPE thermosetting armoured cables", Table 8 Three
core stranded:

25mm^2, Approx overall diameter 23.6mm with an extruded bedding, or
23.2mm with a taped bedding.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Cable that looks like SWA but maybe isn't
 

Andy Burns wrote:
Chris Green wrote:

I need to know the size of the cable because I'm moving
the CU and will need to extend the incomer. I'll be crimping the
add-on so need to get the correct sized tube crimps

Sounds like the sort of job where for a few extra pence, you'd do well
to have the next sizes up and down on hand, just in case ...

:-), yes, that's probably the right approach. I guess it has to be
close enough to either 16sqmm or 25sqmm to make a satisfactory crimp.
The only trouble is that I'll need both 16sqmm and 25sqmm for the
extension cable.

--
Chris Green
·

Cable that looks like SWA but maybe isn't
 

Harry Bloomfield, Esq. wrote:
Chris Green submitted this idea :
I'll be crimping the
add-on so need to get the correct sized tube crimps (I have a
hydraulic crimp tool).

What, you are adding an extra piece onto the existing bit?

Why not just get one piece long enough end to end, to avoid joints?

Because it's about 30 metres long and buried. These aren't meter
tails. The meter is in the garage, with the company fuse and then
there's a time delayed RCD (we're TT) feeding a henley block which, in
turn feeds a 'garage' consumer unit and a switch fuse which goes into
the underground cable to the house.

--
Chris Green
·

Cable that looks like SWA but maybe isn't
 

John Rumm wrote:
On 28/07/2019 22:04, Chris Green wrote:
I am trying to identify the cable that feeds our house consumer unit.
It was buried many years ago, before 1998 at least and quite likely
some years before that.

It's not a 'company' cable, the company fuse is outside, it used to
feed from an outdoor meter/company fuse, it now feeds (after a
re-route under the drive) from meter and company fuse in the garage.

It might be pre-metric SWA, the outside diameter is just over 23mm and
looks somewhat like black SWA. It's a three core cable with Red, Blue
and Yellow insulated cores.


Depending on how much "just over" is, I would guess you either have:

From BS 6346:1997 "PVC Insulated armoured cables...", Table 9 Three
core 600/1000V cables with stranded conductors:

Nominal cross section 16mm^2, Approx overall diameter 23.1mm

Of from BS5467 1997 "XLPE thermosetting armoured cables", Table 8 Three
core stranded:

25mm^2, Approx overall diameter 23.6mm with an extruded bedding, or
23.2mm with a taped bedding.

Brilliant, thanks John, I think it's nearer the second of those two so
I think I have 25sqmm. I'd better get some 16sqmm tube crimps as well
though, just in case, not much money. I need to check what cable I
have, if any, though.

--
Chris Green
·

Cable that looks like SWA but maybe isn't
 

Harry wrote:

Chris Green submitted this idea :
I'll be crimping the
add-on so need to get the correct sized tube crimps (I have a
hydraulic crimp tool).

What, you are adding an extra piece onto the existing bit?

Why not just get one piece long enough end to end, to avoid joints?

Personally, if that involved digging up concrete I might compromise and
join it. Were actual copper sizes ever Imperial, or have they been
metric ever since SWA was invented? If the wire is not metric then it
would be difficult to crimp it to a metric one.

--

Roger Hayter

Cable that looks like SWA but maybe isn't
 

Roger Hayter wrote:
Harry wrote:

Chris Green submitted this idea :
I'll be crimping the
add-on so need to get the correct sized tube crimps (I have a
hydraulic crimp tool).

What, you are adding an extra piece onto the existing bit?

Why not just get one piece long enough end to end, to avoid joints?

Personally, if that involved digging up concrete I might compromise and
join it. Were actual copper sizes ever Imperial, or have they been
metric ever since SWA was invented? If the wire is not metric then it
would be difficult to crimp it to a metric one.

It's not under concrete but it is pretty deep under a large gravel
drive and I'm not even sure of the exact route it takes. I know it's
quite deep because 15 years or so ago when the supply company put the
incoming supply underground they left a hole for me to join the feed
to the house (which used to go to the 'meter on a pole' we had before)
to a new cable run from the new meter and company fuse in the garage.
If my memory serves me right it was a good meter underground. I did
that join with a proper underground splicing kit but my memory doesn't
extend to what size the cable was! :-)

I *might* use a henley block to do the join initially and then, having
got full access to the cable I will know the size and can get the
right size crimp tube and extra cable.

--
Chris Green
·

Cable that looks like SWA but maybe isn't
 

On 29/07/2019 11:44, Chris Green wrote:
John Rumm wrote:
On 28/07/2019 22:04, Chris Green wrote:
I am trying to identify the cable that feeds our house consumer unit.
It was buried many years ago, before 1998 at least and quite likely
some years before that.

It's not a 'company' cable, the company fuse is outside, it used to
feed from an outdoor meter/company fuse, it now feeds (after a
re-route under the drive) from meter and company fuse in the garage.

It might be pre-metric SWA, the outside diameter is just over 23mm and
looks somewhat like black SWA. It's a three core cable with Red, Blue
and Yellow insulated cores.


Depending on how much "just over" is, I would guess you either have:

From BS 6346:1997 "PVC Insulated armoured cables...", Table 9 Three
core 600/1000V cables with stranded conductors:

Nominal cross section 16mm^2, Approx overall diameter 23.1mm

Of from BS5467 1997 "XLPE thermosetting armoured cables", Table 8 Three
core stranded:

25mm^2, Approx overall diameter 23.6mm with an extruded bedding, or
23.2mm with a taped bedding.

Brilliant, thanks John, I think it's nearer the second of those two so
I think I have 25sqmm. I'd better get some 16sqmm tube crimps as well
though, just in case, not much money. I need to check what cable I
have, if any, though.


Where are you based Chris? I could call in and offer site advice
depending where you are. I do travel the country quite a bit for work.

--
Adam