Outside lighting in a garden run in swa

[davesparks]

SWA. in the ground can degrade over time, systems not maintained, just treat it as you would the farm animals, and up the danger levels... An extra rod at the end of the system will give you the extra belt and braces on tripping speeds over long runs for not a lot of cash. Just think of kids playing in a garden with nothing on their feet.

What makes you say that modern SWA cable will degrade over time? What causes this degradation of the non-biodegradable sheath?
This doesn't make any sense to me, if the rod at the far end of the circuit is of a low enough resistance to earth to make any real difference then you will be diverting fault currents from any part of the installation through this lighting circuit.
Kids playing in the garden with nothing on their feet won't be helped by the extra rod, in fact it could just lead to a greater risk by creating an area with a potential gradient on the ground during fault conditions.

 

[davesparks]

Why are you doing this with a mains feed. Given the wide range of LED's available there is no need to use more than 12v for anything in the garden and it greatly reduces the hazard to gardeners digging too enthusiastically. RCBO to mains/12v transformer then distribute.

Have you considered section 715 at all?

Volt drop is a significant factor at 12V and you will have to install ridiculously oversized cables to overcome it. 715.525 effectively places a 5% limit on the volt drop in the ELV installation, so total VD for a 12V supply should not exceed 0.6V

Also why use an rcbo to feed the transformer?

 

[Reynard]

Outdoor lighting? I would suggest solar powered outdoor lighting. Not only are solar lights self-sufficient but they also provide sustainable lighting. Click here to learn more about these eco-friendly lights!

 

[Rocboni]

Method I would go for is definitely Wiska boxes on unistrut, a buried joint using resin would be great but even the best quality light fittings have failures, you don't want to have to cut out the joint to replace a light fitting.