So, I have somewhat changed my plan for feeding power to the new shed
(well, it's a summer house really). As per previous questions I was
going to run the power suspended from a catenary wire but that
produces appearance/cosmetic issues at the destination so I've decided
to bury it.

However the first several metres will run along the back of the (3
car) garage which results in a few questions:-

How low can it be? I want it to be as low as possible really.
There's little risk of collision damage as there isn't even a path
there for people, let alone any sort of vehicle.

How should one fix it? Is there any requirement for fixings to be
fireproof?


Then on to terminations:-

Is it correct/normal to just put the (correct sized) glands in a
hole in the side of the CU or is an intermediate junction box of
some sort the normal way?


Finally as regards the buried bit:-

How does one start/finish? It can't stay 500mm deep all the way! :-)
At one end it runs into a slope, can it just go horizonatlly until
the required depth is reached? (OK, I guess this is down to what
seems right to some extent but any guidance would be welcome)



--
Chris Green
·

Chris Green wrote:

How low can it be?

as low as you like

How should one fix it?

https://screwfix.com/p/cleats/99897

Is there any requirement for fixings to be fireproof?

If it's low down, it's not likely to fall in anyone's way, not sure what
the new regs say though

These look a bit overkill for domestic use

https://www.cmp-products.com/cable-cleats/product-range/metallic-cable-cleats/


Is it correct/normal to just put the (correct sized) glands in a
hole in the side of the CU or is an intermediate junction box of
some sort the normal way?

sometimes it's easier to end the armour on a separate box, and then feed
the inner part into the CU, or even join to a separate T&E

On Sunday, 27 January 2019 17:03:05 UTC, Chris Green wrote:
Finally as regards the buried bit:-

How does one start/finish? It can't stay 500mm deep all the way! :-)
At one end it runs into a slope, can it just go horizonatlly until
the required depth is reached? (OK, I guess this is down to what
seems right to some extent but any guidance would be welcome)

You could thread the part that enters the ground through some flexible
plastic conduit to give a bit of extra protection when somebody decides
to clear the weeds with a strimmer. This is just so that the plastic
sheath of the SWA remains intact, protecting the armour wires from
eventually rusting.
John

On 27/01/2019 17:20, Andy Burns wrote:
Chris Green wrote:

Â*Â*Â*Â* How low can it be?

as low as you like

Â*Â*Â*Â* How should one fix it?

https://screwfix.com/p/cleats/99897

Is there any requirement for fixings to be fireproof?

If it's low down, it's not likely to fall in anyone's way, not sure what
the new regs say though

These look a bit overkill for domestic use

https://www.cmp-products.com/cable-cleats/product-range/metallic-cable-cleats/



Â*Â*Â*Â* Is it correct/normal to just put the (correct sized) glands in a
Â*Â*Â*Â* hole in the side of the CU or is an intermediate junction box of
Â*Â*Â*Â* some sort the normal way?

sometimes it's easier to end the armour on a separate box, and then feed
the inner part into the CU, or even join to a separate T&E

Yes. I ran T&E from the house CU, under the floor, before exiting
through the wall, directly into the back of a junction box. From there
SWA runs to the garage, passing in through the wall, before terminating
in another JB, which is in turn connected to the garage fusebox with T&E
running in conduit.

I'd not want the struggle of terminating SWA directly into the consumer
unit or the large bend radius needed after passing into the garage
before changing direction.

SteveW

On Sunday, 27 January 2019 17:03:05 UTC, Chris Green wrote:

So, I have somewhat changed my plan for feeding power to the new shed
(well, it's a summer house really). As per previous questions I was
going to run the power suspended from a catenary wire but that
produces appearance/cosmetic issues at the destination so I've decided
to bury it.

However the first several metres will run along the back of the (3
car) garage which results in a few questions:-

How low can it be? I want it to be as low as possible really.
There's little risk of collision damage as there isn't even a path
there for people, let alone any sort of vehicle.

How should one fix it? Is there any requirement for fixings to be
fireproof?


Then on to terminations:-

Is it correct/normal to just put the (correct sized) glands in a
hole in the side of the CU or is an intermediate junction box of
some sort the normal way?


Finally as regards the buried bit:-

How does one start/finish? It can't stay 500mm deep all the way! :-)
At one end it runs into a slope, can it just go horizonatlly until
the required depth is reached? (OK, I guess this is down to what
seems right to some extent but any guidance would be welcome)

Can SWA be laid on the ground where there is no possibility of vehicles or walking, in a situation where neither burial nor suspension is satisfactory? I assume not.

You can get plastic coated metal P clips.


NT

On Monday, 28 January 2019 00:13:14 UTC, wrote:
Can SWA be laid on the ground where there is no possibility of vehicles
or walking, in a situation where neither burial nor suspension is
satisfactory? I assume not.

It can be, but is there a risk that it would get covered with debris and then cut into with a spade accidentally?

Owain

On Monday, 28 January 2019 08:24:06 UTC, wrote:
On Monday, 28 January 2019 00:13:14 UTC, tabby wrote:

Can SWA be laid on the ground where there is no possibility of vehicles
or walking, in a situation where neither burial nor suspension is
satisfactory? I assume not.

It can be, but is there a risk that it would get covered with debris and then cut into with a spade accidentally?

Owain

No. Do the regs permit it after a risk assessment?


NT