UK Local RCBO protecting ring final alteration.

[154988]

Hi
I completed a job recently where a hotel reception had a new desk fitted. The old desk dado was supplied via an RCD spur from the existing ring. This ring is fed from one of the very old Merlin single phase boards which I’ve been told you cannot retrofit Schneider ic60n RCBO’s in. I had to remove a couple of sockets including the existing Rcd spur from a wall backing on to a riser as the new desk needed to be flush to this wall. The existing ring was fed in pvc tube down the riser and rear entry to the sockets. Instead of using an Rcd spur to protect my alteration at this point (x4 sockets 2.5 radial in dado) is there a regs issue with instead fitting a single module plastic enclosure with a B16 RCBO - no main switch just the ring terminated straight into the RCBO? - circuit is supplied via C32 MCB. (Enclosure mounted in the riser with 2.5 LSF glanded out the bottom and penetrating the wall through to the desk dado.

Interested to hear thoughts on this.
Thanks

 

[Pretty Mouth]

I personally don't see an issue with this. A 16A breaker offers very similar overload protection to a 13A fused spur.

 

[Simon47]

I wouldn't see any problem either, but ...
If you look in the book it says you can use BS1363 devices on an RFC - it's one of the conditions for having an RFC where the CCC of tbe cable is lower than the rating of the circuit protection.
We then get into semantic arguments. If the regs say you use BS1363 devices, does this implicitly prohibit other devices ?

 

[Pretty Mouth]

I wouldn't see any problem either, but ...
If you look in the book it says you can use BS1363 devices on an RFC - it's one of the conditions for having an RFC where the CCC of tbe cable is lower than the rating of the circuit protection.
We then get into semantic arguments. If the regs say you use BS1363 devices, does this implicitly prohibit other devices ?

Who knows? There's this, in the OSG app H:

"Permanently connected equipment should be locally protected by a fuse complying with BS 1362 of rating not exceeding 13 A or by a circuit-breaker of rating not exceeding 16 A and should be controlled by a switch, where needed (see Appendix J)."

Based on that, I suppose the IET aren't completely against the idea of using MCBs on ring finals.