dual rcd?

[LoveRocket]

RCDs for any non-protected cable buried less than 50mm, thus meaning pretty much all circuits including lighting? A bridge too far.

If you dont like it, run the lighting cables in metal conduit and SWA or MICC. Its the simple answer to a robust lighting circuit.

More than one way to skin a rabbit.

Of course, there are always methods, but I was thinking more of existing (relatively recent) installations where the lighting is already in T+E and it's just a CU upgrade.

Is split-concentric allowable for non-RCD buried cables?

 

[Steve]

Is split-concentric allowable for non-RCD buried cables?

Yup. Its probably the easiest of the protected cables to use, but the least widely available. I dont think its allowed for switch drops though, due to the presence of a live conductor in the outer sheath.

IMO, the best thing for switch drops is metal conduit, earthed at the switch by the T&E it carries. I believe RF lighting has done a retro-fit installation like this.

 

[Spark123]

I don't think split concentric is on the list of allowable cables for being concealed in a wall or partition <50mm without RCD protection.

 

[RF Lighting]

Yep. I also like to use steel conduit on new jobs to keep certain circuits off RCD such as cookers etc.