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Inline Ring RCD and Spur whats allowed?

Former Community Member
Former Community Member
I am looking at a job where I have been asked to extend the ring circuit, which there is no issue. By modifying the circuit, I need to add rcd protection. The c.u is a old MK Sentry MCB board with the ring on a 5930 MCB. I tried to fit a new MK sentry rcbo, but the busbar terminal height is different.

I am thinking of putting a RCD enclosure just under the C.U. I would need to extend the cables by 32A Wagos. The question is could I take a 4mm from the MCB down to the RCD, then from the RCD another 4mm back to the 3 x 3port wagos connecting it to the ring, Is this acceptable? 

The client client also wants a socket added below the c.u. There is no available mcbs. I planned on taking a 2.5mm spur from the proposed new rcb enclosure to the 1 x 2gang socket. Anyone see any issues, non-regs compliance with this?

Hope this all makes sense.  i20210519_153150.jpg
20210519_094209.jpg
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    I see no obvious issue with what you propose, certainly a spur to a socket at or near the origin is OK, and a ring as a 'lollipop' with a 4mm stalk is also a perfectly safe arrangement. keep an eye on cable routes and grouping factors and how you get the new cable and connectors into the space that may be tight,  you may need another socket box and  a blanking cover just to cover the connectors if they cant be fitted in neatly

    Take care if you need to thread behind that  lower bus-bar and in general watch the hole sizes in that CU. If you manage to split any ageing plastic bits, spares will be impossible.. If it was more to be done  than just this, then at some point a new CU maybe in order. but for now it is presumably not a problem.

    A short length of surface trunking can be used to meet the finger proofing requirement.

    I presume there is a good reason not to put the RCD on the side of the CU that  the ring cables are actually outbound, to save on the wagos ?



    Mike.

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