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.

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.