But it would be non compliant would it not. As the max demand calculated according to official publications would certainly be over 60A, probably over 80A, and possibly over 100A.

For a non-compliance you'd have to contradict something in BS 7671 itself - and BS 7671 doesn't specify any particular method of calculating max demand. Many designers use differing methods - in commercial for example it's common to use a Watts per sq metre of floor space approach and ignore circuit based calculation all together. In general supporting publications are taken as advise or guidance, and the OSG in particular is notorious for making assumptions that'll err on the side of safety under the worst possible conditions. So in general there's no objection, certainly no non-compliance, in adopting other methods provided they give valid results for your particular situation. I think the OSG specifically used to say in the introduction to the section on diversity that figures were only for guidance and special knowledge and experience could increase or decrease them. Also most of those tables have remained unchanged for many decades - long before the introduction of EVSE.

   - Andy.

But it would be non compliant would it not. As the max demand calculated according to official publications would certainly be over 60A, probably over 80A, and possibly over 100A.

For a non-compliance you'd have to contradict something in BS 7671 itself - and BS 7671 doesn't specify any particular method of calculating max demand. Many designers use differing methods - in commercial for example it's common to use a Watts per sq metre of floor space approach and ignore circuit based calculation all together. In general supporting publications are taken as advise or guidance, and the OSG in particular is notorious for making assumptions that'll err on the side of safety under the worst possible conditions. So in general there's no objection, certainly no non-compliance, in adopting other methods provided they give valid results for your particular situation. I think the OSG specifically used to say in the introduction to the section on diversity that figures were only for guidance and special knowledge and experience could increase or decrease them. Also most of those tables have remained unchanged for many decades - long before the introduction of EVSE.

   - Andy.