"jim_in_sussex" wrote in message
om...
Planning to bring my garage supply (which has a workshop section) up
to date in Christmas week. (last legal throw before part P)

A thread ran a few weeks back on running a supply cable from a house
to a (detached) garage & SWA cable was suggested. To take up that
suggestion advice is needed as it is a long time since I used SWA
cable (& then only once).

1. Rating: It would be buried (as per above thread) about 450mm
(18ins) underground (hard drive/path) - about 4m as the crow flies,
but 7m-12m after deviations round, up & down. Is it correct to use
IEE table 4D1A/ref method 1? (the illustrations for method 1 don't
refer specifically to underground use).

2. Ducting: Instead of burying it in bare soil it looks more sensible
to run it inside a duct, but attempts to source underground ducting
have failed. Does anyone know of a source, or failing that, could
semi-flexible 40mm waste pipe be used? If SWA is ducted, how does it
affect current rating?

3. Termination: The house end is no problem as that connects into a
metal enclosure which I know how to connect, but how do you connect
the garage end into a standard plastic consumer unit? Is there a
special gland for this? Or do you connect into a service block of
some type & then run the last 12 ins or so in tails?

I bought a metal enclosure box, one with knockout holes in it IIRC, and used
it as a cable changing box. If you buy the SWA cable glands you will be able
to bend the steel armouring back over the tapered collet thingy ( need to
trim it just right though ), and screw the gland together tight, compressing
the steel armouring and thus getting what I believe to be a very good
bonding. I think the cable gland kits also come with a terminal washer,
which I assembled onto the gland as I screwed it into the cable-changing box
with the nut that is supplied, and soldered a wire onto the terminal washer
, the other end of the wire going to a stud on the box, sort of belt and
braces really. I used a metal cable-changing box at both ends actually, as I
didn't consider the pvc boxes to be strong enough to take the rather stiff
SWA to, and with metal you get a direct earth bond as well. Use some heavy
duty terminal block inside the CCB to connect the cables together, at least,
that's how I did it. You will need a grommet for the PVC cable as it exits
the ccb.

Andy.

4. Earthing: I'm not completely happy about relying on a non-copper
earth (ie the steel armour). Instead can I use 3 core SWA & use the
3rd core as earth to supplement the armour? Common advice seems to
be to avoid using the house earth, but if possible I'd like to avoid
the work involved in installing an earth rod. The house supply is
100amp PME/TN-C-S.

5. Cable size: nominally 6mmsq cable is adequate for the garage load
(ring + freezer radial + lights), but am wondering about using a
larger cable - eg 16mmsq. There'd be 2 benefits - much lower volt
drop, plus less light flicker when a machine starts. Relative to the
whole project the extra cost is small, but are there any practical
snags? Does anyone know the outside diameter of these cables?

6. Finally looking up the ratings for these cables in the IEE regs &
comparing with the TLC catalog, why the differences? eg TLC show swa
16mmsq 2 core (6942x) as 91amps, IEE table 4D4A shows 89amps. In fact
most cable amp values given by TLC are lower than the IEE tables
give.

Many thanks for all help offered.

Planning to bring my garage supply (which has a workshop section) up
to date in Christmas week. (last legal throw before part P)

A thread ran a few weeks back on running a supply cable from a house
to a (detached) garage & SWA cable was suggested. To take up that
suggestion advice is needed as it is a long time since I used SWA
cable (& then only once).

1. Rating: It would be buried (as per above thread) about 450mm
(18ins) underground (hard drive/path) - about 4m as the crow flies,
but 7m-12m after deviations round, up & down. Is it correct to use
IEE table 4D1A/ref method 1? (the illustrations for method 1 don't
refer specifically to underground use).

2. Ducting: Instead of burying it in bare soil it looks more sensible
to run it inside a duct, but attempts to source underground ducting
have failed. Does anyone know of a source, or failing that, could
semi-flexible 40mm waste pipe be used? If SWA is ducted, how does it
affect current rating?

3. Termination: The house end is no problem as that connects into a
metal enclosure which I know how to connect, but how do you connect
the garage end into a standard plastic consumer unit? Is there a
special gland for this? Or do you connect into a service block of
some type & then run the last 12 ins or so in tails?

4. Earthing: I'm not completely happy about relying on a non-copper
earth (ie the steel armour). Instead can I use 3 core SWA & use the
3rd core as earth to supplement the armour? Common advice seems to
be to avoid using the house earth, but if possible I'd like to avoid
the work involved in installing an earth rod. The house supply is
100amp PME/TN-C-S.

5. Cable size: nominally 6mmsq cable is adequate for the garage load
(ring + freezer radial + lights), but am wondering about using a
larger cable - eg 16mmsq. There'd be 2 benefits - much lower volt
drop, plus less light flicker when a machine starts. Relative to the
whole project the extra cost is small, but are there any practical
snags? Does anyone know the outside diameter of these cables?

6. Finally looking up the ratings for these cables in the IEE regs &
comparing with the TLC catalog, why the differences? eg TLC show swa
16mmsq 2 core (6942x) as 91amps, IEE table 4D4A shows 89amps. In fact
most cable amp values given by TLC are lower than the IEE tables
give.

Many thanks for all help offered.

On 17 Dec 2004 14:59:49 -0800,
(jim_in_sussex) strung together this:

1. Is it correct to use
IEE table 4D1A/ref method 1? (the illustrations for method 1 don't
refer specifically to underground use).

I don't have any regs to hand, I'm sure someone else will.

2. Ducting: Instead of burying it in bare soil it looks more sensible
to run it inside a duct,

Why? Unless you're likely to be pulling it out then bury it direct.
There's no mechanical advantage to be gained from running SWA in a
duct.
The current rating will be the same.

3. Termination: how do you connect
the garage end into a standard plastic consumer unit?

Two ways, first is to terminate directly into the PVC enclosure and
the second is to terminate into an external PVC or metallic enclosure
then run from this to the CU with T&E or something similar.

4. Earthing: I'm not completely happy about relying on a non-copper
earth (ie the steel armour).

I always use 3 core SWA and use the 3rd core as an earth. Common
practice really.
Earthing, I'm not going to get into this one.

5. Cable size: nominally 6mmsq cable is adequate for the garage load
(ring + freezer radial + lights), but am wondering about using a
larger cable - eg 16mmsq. There'd be 2 benefits - much lower volt
drop, plus less light flicker when a machine starts. Relative to the
whole project the extra cost is small, but are there any practical
snags? Does anyone know the outside diameter of these cables?

6mm about 20mm OD, 16mm about 30mm OD. You can use either, I'd go for
anything from 6mm upwards for a 32A supply over the distance you've
got.

6. Finally looking up the ratings for these cables in the IEE regs &
comparing with the TLC catalog, why the differences?

Email TLC and ask, could be a number of reasons.
--

SJW
Please reply to group or use 'usenet' in email subject

6. Finally looking up the ratings for these cables in the IEE regs &
comparing with the TLC catalog, why the differences?

Email TLC and ask, could be a number of reasons.

XLPE probably (modern higher temp rating).
Think it was XLE that deteriorated over time for HV links & went boom.

2. Ducting: Instead of burying it in bare soil it looks more sensible
to run it inside a duct,

No need, but do lay a "cable buried below".
o Ducting is good at filling with water
o Ducting =/= run net/phone cable next to power cable
o Ducting = run net/phone cable in flex-conduit next to power cable

5. Cable size: nominally 6mmsq cable is adequate for the garage load
(ring + freezer radial + lights), but am wondering about using a
larger cable - eg 16mmsq.

Consider how long your ring-main loop can be serving a typical 50m^2
area (subject to voltage drop & earth disconnect time). Your proposed
run is only a few metres, and XPLE cable rating is higher than PVC FTE,
so 16mm^2 may be somewhat overkill unless you can on a shower :-)

Note the XLPE rating (which is re higher temp insulation IIRC) may be a
factor in your sizing of FTE to feed it from the CU or from it to other CU.

If you are using big enough machinery to really cause the lights to dim:
o Consider a non-maintained emergency light in the garage (£19-22)
---- whole-garage RCD = lights go out & excitement begins
o Consider a garage CU with RCBO for ring, plain MCB for lights/freezer
---- new MK/Hager/MG 1-module 32A RCBO is £19-26 are regular on Ebay
--
Dorothy Bradbury

"Lurch" wrote in message
...
On Fri, 17 Dec 2004 14:46:23 -0000, "andrewpreece"
strung together this:

snip

Your clocks wrong, thrash your self with 2.5mm T&E now.
--
Only 12 hours out, picky, picky, picky... :0)

Andy.

jim_in_sussex wrote:

1. Rating: It would be buried (as per above thread) about 450mm
(18ins) underground (hard drive/path) - about 4m as the crow flies,
but 7m-12m after deviations round, up & down. Is it correct to use
IEE table 4D1A/ref method 1? (the illustrations for method 1 don't
refer specifically to underground use).

I take it you found TLCs voltage drop calculator?

http://www.tlc-direct.co.uk/Technica...ltageDrop.html

Quite handy for SWA I find.


--
Cheers,

John.

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

On Fri, 17 Dec 2004 14:46:23 -0000, "andrewpreece"
strung together this:

snip

Your clocks wrong, thrash your self with 2.5mm T&E now.
--

SJW
Please reply to group or use 'usenet' in email subject

On Sat, 18 Dec 2004 00:34:35 GMT, "Dorothy Bradbury"
strung together this:

Don't reply to me, I didn't ask the question. Bloody OE users....

2. Ducting: Instead of burying it in bare soil it looks more sensible
to run it inside a duct,

No need, but do lay a "cable buried below".
o Ducting is good at filling with water
o Ducting =/= run net/phone cable next to power cable

No, you use seperate ducts for power and low voltage services.
--

SJW
Please reply to group or use 'usenet' in email subject

On 17 Dec 2004 14:59:49 -0800, (jim_in_sussex) wrote:

Planning to bring my garage supply (which has a workshop section) up
to date in Christmas week. (last legal throw before part P)

A thread ran a few weeks back on running a supply cable from a house
to a (detached) garage & SWA cable was suggested. To take up that
suggestion advice is needed as it is a long time since I used SWA
cable (& then only once).

1. Rating: It would be buried (as per above thread) about 450mm
(18ins) underground (hard drive/path) - about 4m as the crow flies,
but 7m-12m after deviations round, up & down. Is it correct to use
IEE table 4D1A/ref method 1? (the illustrations for method 1 don't
refer specifically to underground use).

2. Ducting: Instead of burying it in bare soil it looks more sensible
to run it inside a duct, but attempts to source underground ducting
have failed. Does anyone know of a source, or failing that, could
semi-flexible 40mm waste pipe be used? If SWA is ducted, how does it
affect current rating?

SWA is designed to be buried - save the ducting for phone, network, doorbell, whatever. Remember to
run some string through for future pulls.

3. Termination: The house end is no problem as that connects into a
metal enclosure which I know how to connect, but how do you connect
the garage end into a standard plastic consumer unit? Is there a
special gland for this? Or do you connect into a service block of
some type & then run the last 12 ins or so in tails?

You can get metal glands with tags for terminating to the armour.

4. Earthing: I'm not completely happy about relying on a non-copper
earth (ie the steel armour). Instead can I use 3 core SWA & use the
3rd core as earth to supplement the armour? Common advice seems to
be to avoid using the house earth, but if possible I'd like to avoid
the work involved in installing an earth rod. The house supply is
100amp PME/TN-C-S.
That's what I did - use the 3rd as earth, but also earth the SWA, in case it ever gets a
spade/digger through it..!

5. Cable size: nominally 6mmsq cable is adequate for the garage load
(ring + freezer radial + lights), but am wondering about using a
larger cable - eg 16mmsq. There'd be 2 benefits - much lower volt
drop, plus less light flicker when a machine starts. Relative to the
whole project the extra cost is small, but are there any practical
snags? Does anyone know the outside diameter of these cables?

I think 16 would be a nightmare to handle - the bend radius is probably of the order of a foot or
two. Maybe split the difference and use 10.

On Sat, 18 Dec 2004 11:03:10 GMT, Mike Harrison
strung together this:

Sorry Mike but is there any chance you could adjust your line
length\character width to 70 characters or thereabouts? It makes posts
rather difficult to read.
Thankyou.
--

SJW
Please reply to group or use 'usenet' in email subject

"jim_in_sussex" wrote
| 3. Termination: The house end is no problem as that connects
| into a metal enclosure which I know how to connect, but how
| do you connect the garage end into a standard plastic consumer
| unit? ... Common advice seems to be to avoid using the house
| earth, but if possible I'd like to avoid the work involved
| in installing an earth rod. The house supply is 100amp PME/TN-C-S.

AIUI PME earths should not be exported from the house. It would be normal to
use 2-core SWA, use an earthing gland at the house end so that the armour is
earthed, use an insulating gland at the garage end so that the armour is
insulated. The CU is then earthed to an earth rod (TT) and all circuits
should be RCD protected. If you use power tools in your workshop you should
consider discrimination between lighting and power circuits, so that in the
event of an RCD trip you are not left in the darkness with power tools
spinning down. An alternative might be a couple of self-contained emergency
lighting units.

Owain

"Lurch" wrote...
Don't reply to me, I didn't ask the question. Bloody OE users....

Sorry Lurch.
o Yes I similarly loathe Outlook (in this case)
o One reason I'm migrating to Linux - that and multiple O/S fees

No, you use seperate ducts for power and low voltage services.

Even if the LV is conduited?
I guess I'm thinking of the MK etc skirting trunking.
That allows LV & Mains in the same trunking due to separated design,
ie, it's little more than several trunking c/sections extruded as one piece.

Thanks for the correction.
--
DB.

On Sat, 18 Dec 2004 17:49:59 GMT, "Dorothy Bradbury"
strung together this:

Sorry Lurch.

Apology accepted! ;-)

o Yes I similarly loathe Outlook (in this case)
o One reason I'm migrating to Linux - that and multiple O/S fees

Well done. I started doing that a while ago.

Even if the LV is conduited?
I guess I'm thinking of the MK etc skirting trunking.
That allows LV & Mains in the same trunking due to separated design,
ie, it's little more than several trunking c/sections extruded as one piece.

Theoretically, you're correct, but if there is a duct with an SWA in
it then it is a mains duct, them's the rules!
If you were to place a duct within a duct then you could do it but you
don't need to, you would just bury the SWA direct and use the duct for
LV.
--

SJW
Please reply to group or use 'usenet' in email subject

"andrewpreece" wrote in message
...

"Lurch" wrote in message
...
On Fri, 17 Dec 2004 14:46:23 -0000, "andrewpreece"
strung together this:

snip

Your clocks wrong, thrash your self with 2.5mm T&E now.

Only 12 hours out, picky, picky, picky... :0)

Andy.


But that means the post you sent today didn't arrive until yesterday. So
you've already missed all the good parts. :-)

jim_in_sussex wrote:

Is it correct to use IEE table 4D1A/ref method 1? (the illustrations
for method 1 don't refer specifically to underground use).

No, for XLPE insulated SWA (to BS 5467) use Table 4E4A. Current rating
is rarely an issue for SWA uses such as this; voltage drop is usually
the limiting factor.

2. Ducting: Instead of burying it in bare soil it looks more sensible
to run it inside a duct, but attempts to source underground ducting
have failed. Does anyone know of a source, or failing that, could
semi-flexible 40mm waste pipe be used? If SWA is ducted, how does it
affect current rating?

SWA is _intended_ for direct burial, as others have said. If you want
to use duct you can get 6m lengths of push-fit service ducting from your
local builder's merchant.

5. Cable size: nominally 6mmsq cable is adequate for the garage load
(ring + freezer radial + lights), but am wondering about using a
larger cable - eg 16mmsq. There'd be 2 benefits - much lower volt
drop, plus less light flicker when a machine starts. Relative to the
whole project the extra cost is small, but are there any practical
snags? Does anyone know the outside diameter of these cables?

For 3-core the o/d for 6mm^2 is 17.0mm and for 16mm^2 it's 22.4mm (and
19.9mm for 10mm^2). [figures from Pirelli data sheet]

6. Finally looking up the ratings for these cables in the IEE regs &
comparing with the TLC catalog, why the differences? eg TLC show swa
16mmsq 2 core (6942x) as 91amps, IEE table 4D4A shows 89amps. In fact
most cable amp values given by TLC are lower than the IEE tables
give.

The TLC figures might be out-of-date info for the older BS 6346 PVC
insulated SWA cables. Table 4E4A gives 110 A (method 1) for 16mm^2. I
advise ignoring any cable current ratings given in re-sellers'
literature as they're frequently wrong. The Pirelli data sheet gives
ratings of 141 A for direct-in-ground, and 115 A in duct, the latter
agrees with 4E4A method 12.

--
Andy