Andrew Procter

Wed 09 Jul 2014 08:41am

No it is not necessary to have RCBO's instead of RCD's. The advantage of an RCBO is that it only trips out the circuit with the earth fault, whereas an RCD protecting several circuits will cut power to all the circuits it is protecting. You don't want all your circuits on just one RCD, or you will lose all your circuits together if there is an earth fault. Not considered to be good practise. There are split load boards available with two RCD's, and we divide the circuits between them to minimise inconvenience in the event of a fault. RCBO's are more expensive to buy. They give the protection of RCD and MCB in the one unit. Which option is best for your installation will depend on how many circuits you have and what they are etc.. It can sometimes be an advantage to have both in the same consumer unit. Hope this helps explain it, regards Andy

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Chris Brown

Tue 08 Jul 2014 09:24am

Ab rcbo generally protects only one circuit. An rcd usually protects a number of circuits. Just that if you have earth fault on sockets, then you may lose power to others also

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Bogdan Banasiewicz

Tue 08 Jul 2014 07:32am

In general it is not necessary use RCBO if you have RCD in fuse box . RCBO are generally a single pole overload device combined with a single pole earth fault device. The separate option is still a single pole overload with a double pole out of balance device. Faulty RCD is generally an easy on site test. A faulty mcb is a much more difficult test on site apart from go/no go. Bogdan Proton Proton on facebook

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