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Three Phase RCD & MCB Wiring?

Nano Brewery
Please could somebody advise on the most cost effective procedure of wiring up RCDs & MCBs on a DIN Rail for independent circuit protection.  Tried Googling to no joy.  Plenty of Single Phase advice, images, videos.  If using 4 Pole MCBs & RCDs, would I be correct in assuming that similar to single phase, it's just a case of Busbar-ing the MCB Lives to the RCD Lives and taking the RCD to Neutral Bar?


Have seen diagrams (like below) where the Incoming L1, L2, L3 get split to separate DP MCBs, RCDs and SP MCBs for each phase.  Seems like a bit of a faff and a pricey option (3x DP MCBs + 3x RCDs + 3x SP MCBs) per circuit.


I have 3x Three Phase Circuits (13A, 40A, 48A) that I wish to protect independently with RCDs.


Thanks in advance!  Dan.

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  • 0
    ebee:

    Well if you need RCD protection on single phases independently of the two other phases then then yes 3 x RCD (RCCB)  i.e 1 per phase or better still each MCB to be an RCBO (an RCCB & MCB combined in one unit)  instead. If you have any actual 3 phase loads then you need a 3P+N RCD (RCCB) for that circuit only. Not for any single phase circuits.


    ebee.  I have 3x Three Phase Circuits (13A, 40A, 48A).  I wish to protect EACH Three Phase Circuit independently with RCCBs.  Was hoping to avoid the £444 (MCG Industry) cost of the 13A, 40A, 50/63A 3 Pole RCBOs.  Wylex 4P RCCBs & 3P MCBs come to £180 approx.  Cheers.


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  • 0
    ebee:

    Well if you need RCD protection on single phases independently of the two other phases then then yes 3 x RCD (RCCB)  i.e 1 per phase or better still each MCB to be an RCBO (an RCCB & MCB combined in one unit)  instead. If you have any actual 3 phase loads then you need a 3P+N RCD (RCCB) for that circuit only. Not for any single phase circuits.


    ebee.  I have 3x Three Phase Circuits (13A, 40A, 48A).  I wish to protect EACH Three Phase Circuit independently with RCCBs.  Was hoping to avoid the £444 (MCG Industry) cost of the 13A, 40A, 50/63A 3 Pole RCBOs.  Wylex 4P RCCBs & 3P MCBs come to £180 approx.  Cheers.


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