Not exactly a split board but the designer of this distribution arrangement in a church and adjoining hall seems to be stretching semantics. His idea of “minimise” doesn’t square with mine. Every socket circuit in the complex is on the top board which has a 63A 30mA type AC RCD overall. The connectors evident in the top board re-direct the supply to the septic tank which was originally on the socket board but was found to be the cause of multiple tripping events, often interrupting church services and social gatherings. 
Maybe the contractor could counter that he was only being frugal!

It does make one question the value of requirements within a standard that contain verbal forms such as:

• 'shall take into account'
• 'shall be designed to minimize'
• 'shall be provided the maximum practicable extent'

etc.

It's not so much that the intent or sentiment is not understood, but the fact that, for verification purposes, it's not easy to provide an interpretation as to whether the requirement has been satisfied or not by a particular design.

Pedantically, when looking at whether a standard such as BS 7671 has been satisfied, the first thing that ought to happen is each and every clause of the standard ought to be validated, i.e. the question answered "Does it apply to this particular design, and, if so, to what extent?"

Consider a simple example. Regulation 411.3.3 - if there are no socket-outlets rated at 32 A or less in the installation, and no outdoor equipment, the requirement is not applicable to that installation.

However, more complicated is Part 3, because Part 3 sets out fundamental requirements, which are addressed by applying Parts 4, 5, 7 and 8, which are in turn verified by a statement of conformity by the Designer after assessing the fundamental principles (131 and 311 to 313, see 641.2). In the case of the topic of this thread, this is not discussed in sufficient detail in Parts 4, 5, 7 and 8, for us to have a better clue from the remainder of BS 7671 as to whether a split-load board is considered adequate ... and of course that is because in one installation, it might be, and in another, it might not.

As to who carries out this requirements validation process (inspector or designer)? I would say designer, but what if the inspector and/or Client don't agree with the designer? It's easier in a large commercial contract in which the Client will have one or more persons agreeing designs and requirements validation exercises. In larger projects, design is done in stages, and not always by the same legal entity at each stage.

In reality, the enormity if the task at hand (validating 300+ pages of requirements) means it never happens, and I would think that most topics like the one being discussed in this thread are only ever simply something for guidance, rather than considering each installation on is merits - and leaving the reality that such questions are only ever properly answered if they become part of a legal case (criminal prosecution, or civil proceeding that might yield a large enough payout for one side to make it worth going to court and being discussed there).

That looks terribly domestic!

That looks terribly domestic!

For a church it looks terribly good ;-)  Maybe I'm unlucky but there are usually 'Old Bill' switchger with hot wire fuses and TT mains with no RCD in the ones I seem to spot on ringing outings. The trick I find is to feign ignorance so long as the lights stay on for the duration of the visit.

Mike

PS Still that one seems to be due an inspection in 2008 - so the right century at least.