Why can't any SWA be screwed to the fence rather than being in a trench? The last time that I had to prep a log cabin that I had assembled, the electrician wanted a 600(?)mm deep trench from the summer house to the fence and then he ran the rest back to the house at about 200mm above ground on the fence.
Running power to an outside building
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He/she was wrong. Fences blow down. They aren’t solid enough backgrounds.
Fences can be strong, it depends.
It also depends on where on the fence it is and a few few more things too.
600mm gives about 1" for sifted sand, then the SWA then another 1" for sifted sand then at least 6" for a spade depth for your warning tape/bricks then about 16 inches of soil and that should be the minimum depths for a reasonable sort of job. I have known a DNO pt them far less than that and witnessed a pick axe pierce an incoming mains supply, it made an interesting scenario.
PS - That is why my reaction that 1 metre is a good intention for a safe depth if it is achievable - it is a lot more difficult than doing a 600mm depth though) it also puts more pressure on any joints to allow water ingress into any duct and I would factor in that water ingress into any duct is almost always inevitable.
Ref fences etc- I have not run very many supplies outside a building to another location, those I have done underground I have done, bar one, have been 600mm minimum. Another I have done was into a pre-installed drainage pipe at greater depth and alongside existing SWA cable, construction was very good but it still allowed plenty of water in sufficient to be factored in anyway.
I only did install on one fence, it was pretty robust, at a decent height and readily on view therefore avoiding accidental damage risk.
I have been asked to install on a few others on fences but they failed on my opinion of sufficient robustness etc damage risk.
My opinion of ducting is that it primarily might aid replacement or additions if done well.
Second, it might offer a small degree of additional protection in some circumstances if done well.
The reason for the SWA to be surrounded by sifted sand in a trench is to ensure no sharp stones are putting sharp pressure points on the cable. It is difficult to lay a cable on it neatly surrounded in practice as suggested by the theory of it so great care is needed to ensure a half reasonable job. I do not envisage it to do much at all if anything to assist rainwater draining away even if you are convinced it is always above the water table!
It also depends on where on the fence it is and a few few more things too.
600mm gives about 1" for sifted sand, then the SWA then another 1" for sifted sand then at least 6" for a spade depth for your warning tape/bricks then about 16 inches of soil and that should be the minimum depths for a reasonable sort of job. I have known a DNO pt them far less than that and witnessed a pick axe pierce an incoming mains supply, it made an interesting scenario.
PS - That is why my reaction that 1 metre is a good intention for a safe depth if it is achievable - it is a lot more difficult than doing a 600mm depth though) it also puts more pressure on any joints to allow water ingress into any duct and I would factor in that water ingress into any duct is almost always inevitable.
Ref fences etc- I have not run very many supplies outside a building to another location, those I have done underground I have done, bar one, have been 600mm minimum. Another I have done was into a pre-installed drainage pipe at greater depth and alongside existing SWA cable, construction was very good but it still allowed plenty of water in sufficient to be factored in anyway.
I only did install on one fence, it was pretty robust, at a decent height and readily on view therefore avoiding accidental damage risk.
I have been asked to install on a few others on fences but they failed on my opinion of sufficient robustness etc damage risk.
My opinion of ducting is that it primarily might aid replacement or additions if done well.
Second, it might offer a small degree of additional protection in some circumstances if done well.
The reason for the SWA to be surrounded by sifted sand in a trench is to ensure no sharp stones are putting sharp pressure points on the cable. It is difficult to lay a cable on it neatly surrounded in practice as suggested by the theory of it so great care is needed to ensure a half reasonable job. I do not envisage it to do much at all if anything to assist rainwater draining away even if you are convinced it is always above the water table!
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You’d do better to scrap the plastic drain pipe and go for proper ducting if the idea is to allow replacement.
Plastic pipe is more likely to leak at joints or degrade.
Follow installation instructions as some ground movement may happen
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