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.

OlympusMons:

Dan, do you need to have RCD protection for the whole of each circuit? Or just near the ends? It might be better to get a quote to install three 3-phase RCCBs near the ends of your circuits.

The 48A Circuit will be feeding a Control Panel which in turn will be switching 4x individual 3-phase Immersion Elements.  So that would require 4x RCCB Sockets/Plugs.  Quite a pricey option.


The 40A Circuit will be feeding a 3-phase Instant Hot Water Heater.


The 13A Circuit will be feeding a 3-phase Pump.


Cheers.

Chris Pearson:

Is this a re-hash of previous threads?


On the face of it, you simple use an RCBO for each circuit, but as JP says, this is a job for a skilled person.

Hi Chris, I don't think it's a re-hash???...


The previous thread was to understand if RCCBs were required?


This thread is to try and understand how 4 Pole RCCBs and 4 or 3 Pole MCBs are wired up on the DIN Rail? 


Is it even possible?  Or do you have to go the pricey RCBO option?


Cheers.

Nano Brewery:

Chris Pearson:

Is this a re-hash of previous threads?


On the face of it, you simple use an RCBO for each circuit, but as JP says, this is a job for a skilled person.

Hi Chris, I don't think it's a re-hash???...


The previous thread was to understand if RCCBs were required?


This thread is to try and understand how 4 Pole RCCBs and 4 or 3 Pole MCBs are wired up on the DIN Rail? 


Is it even possible?  Or do you have to go the pricey RCBO option?

IIRC, the option of having an RCD incomer was discussed.


It isn't a matter of working out how to connect a confection of different devices.


I dare say that there are plenty of folk out there who will design you an appropriate installation. You may have more difficulty in finding somebody who will do it's initial verification.


So if I brought you some half-brewed beer and asked you to finish it off and bottle it, what response would I get?

AJJewsbury:

That diagram is no good at all for 3-phase final circuits (and actually looks a bit non-conventional for the UK in several areas).


Unfortunately building a (BS 7671 compliant) distribution board these days isn't as simple as picking up the modular devices you require, clipping them onto a DIN rail and wiring them together - the thing as a whole will need type approval to comply with BS EN 61439 (see BS 7671 reg 536.4.203) - which either means that you can only use components specified by the DB manufacturer in the manner the DB manufacturer stipulates, or you take on the rather onerous responsibility of becoming an assembly manufacturer yourself. Some of that requirement might be just bit of manufacturer's blather, but there will be some details (e.g. reaction to overvoltages or breaking large fault currents) that require co-ordination between the individual components, their spacing/positioning and the physical capabilities of the enclosure to contain the products of arcing etc) which could easily catch out the unwary.


So, it would be a lot simpler (and probably safer) to go for an off-the-shelf solution - perhaps an ordinary type B (3-phase) distribution board, with either 3-phase RCBOs or 3-phase MCBs feeding 3-phase RCCBs downstream in their own enclosure.


   - Andy.

Hi Andy,


Apologies for any confusion.  I do intend to use brand new components from the same manufacturer.  Probable Wylex in this situation. 


Was just trying to understand if it is possible to connect/wire up a 4P RCCB and a 4P MCB in the same manner as a 1P RCCB and numerous MCBs?  i.e. By connecting the L1 L2 L3 of the 4P RCCB to the L1 L2 L3 of the 4P MCB via a Busbar or Individual wiring of L1 L2 L3?


Cheers.