joining armoured cable underground

[mrcrow]

we have an armoured cable which used to connect to our garage straight from its own circuit breaker in the fuse box.

it seems to be 2.5mm^2

now the garage has gone and further back in the garden is to be our new shed which i want lighting and a couple of sockets for a freezer and using the lawn mower i need to extend the cable by 10M

can i have any advice please on the best way to join the cables to be laid underground under the to be turfed area of the new garden layout

yours
geof
manchester

 

[YorksSparks]

You can use these;

http://www.tlc-direct.co.uk/Main_Index/Cable_Accessories_Index/Cable_Joints_1/index.html

but myself i would always use these;

http://www.tlc-direct.co.uk/Main_Index/Cable_Accessories_Index/Joints_Resin_Filled/index.html

 

[mrcrow]

You can use these;

http://www.tlc-direct.co.uk/Main_Index/Cable_Accessories_Index/Cable_Joints_1/index.html

but myself i would always use these;

http://www.tlc-direct.co.uk/Main_In..._Index/Joints_Resin_Filled/index.html[/QUOTE]

many thanks...i will get on to them straight away...
i think i also favour the epoxy model since there will be no need to re-acces the cable in the future

cheers
geof

 

[ban-all-sheds]

Have you checked that voltage drop won't be a problem with the longer cable?

Or fault loop resistance?

What tests do you plan to carry out on the cable once it's extended?

If you live in England or Wales are you aware of the law applying to this work?

Do you know what the lowest temperature will be in the shed, and whether the freezer will work at that temperature?

 

[YorksSparks]

Voltage drop calc for you here;

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

What's the total length? Suspect 2.5mm will be too small unless you only plan for a small load at the shed.

Ignore ole misery guts, he just loves to preach the "law" to posters.

 

[RF Lighting]

Ensuring the cable remains within voltage drop limits isn't "preaching the law". It's kind of crucial to make sure the stuff connected to the end of it will actually work

Oh and ensuring the fault loop impedence is low enough. Well that's also crucial to ensuring the circuit is actually safe to use.


And pratley boxes? Really? Have you ever actually tried burrying one and seeing how quickly it fills up with water?

 

[Wontdothatagain]

Ignore ole misery guts, he just loves to preach the "law" to posters.

The testing of the cable after a joint has been made is cruical to ensure that everything will function properly at both ends of the circuit as well as ensuring that the joint has been made properly. Some of these kits are not for DIYers and require a bit of skill to get right.

The OP may not be aware that the job requires notification, is it wrong to point this out? i think not.

 

[Alarm]

That "calc" site is worse than the one I just used on another thread. It Errs radically on the safe side, but gives a smaller cable diameter to be used?

 

[YorksSparks]

Oh, come on fellas, I can't be the only one sick of B-A-S's holier than thou preachy attitude - whatever happened to answering the question that was asked?

I did say I wouldn't ever use a Pratley - didn't I?

Thank God the OP didn't want to put downlighters in...........

 

[RF Lighting]

I don't really think that making sure a circuit remains within the permitted VD and EFLI values is being holier than thou.

This information was provided to the OP who probably didn't know they needed to know it.

What's the point of recommending pratleys if they are rubbish and you would never use them your self?

 

[ban-all-sheds]

That "calc" site is worse than the one I just used on another thread. It Errs radically on the safe side, but gives a smaller cable diameter to be used?

I think you'll find it works fine, as long as you remember two crucial, but undocumented, features:

1) If you specify XLPE it will assume you can run the cable at 90°

2) If you specify 3-core it will assume 3-phase.

 

[Alarm]

And that gives 6mm cable with 11.4 drop.

Sorry, with 2 core @ 30 degrees

 

[bernardgreen]

Thank God the OP didn't want to put downlighters in...........

downlighters buried underground Best place for them

 

[mrcrow]

Thank God the OP didn't want to put downlighters in...........

downlighters buried underground Best place for them

we got a set yesterday...they are solar powered...!
so

i have chosen the plastic box resin way and see the entry holes are pretty small
also they...TLC...seem to suggest... i may need crimps or butt connectors
which is more suitable for the 2.5 armoured cable which is braided

all the other electrical information i will pass on to my electrical installer for his benefit..

i buy the stuff...he does it

finally the shed will have a small fluorescent light...around 1200mm
and two sockets...one for the freezer and one for the lawn mower
there is also a fuse box from the old garage installation which i will have fitted ..it has two fuses one for lighting and one for power..

more info greatly accepted

 

[mrcrow]

Voltage drop calc for you here;

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

What's the total length? Suspect 2.5mm will be too small unless you only plan for a small load at the shed...

Ignore ole misery guts, he just loves to preach the "law" to posters.

....very small load...freezer and lawnmower and 1200 flou lighting...fusebox in shed for each circuit...lights and power
ps i worked as a consulting engineer for structural designs
the ones submitted were always 'wrong' in some respect but fit for the job intended..good job we dont get earthquakes in the uk...if so half will fall down



Cable Type
Application
Circuit Type
Ambient Temperature °C
Number of Circuits
Power
Voltage Volts
Length metres
Required Cable Size 1.5 mm
Voltage Drop 11.3 Volts.
Percentage Drop 4.9%
Current Load 13.0 Amps
Max Cable Load* 14.5 Amps