... hhd; is that really 'your' graph ... ? I seem to remember that it was posted in response to a thread that you started; possibly by a 'dearly beloved' and 'departed' friend! You may correct me if I am wrong. Funnily enough, if the conditions of installation and design of the cable were sufficiently 'similar' to a particular 'case' recorded in a table in BS 7671 then that is the approach that I would take ... so long as the organisation that you work for has plenty of professional indemnity insurance and you or your boss has a big pair of 'cahunas' then I imagine that there shouldn't be too much of a problem. Unless the proverbial hits the fan and someone from that infamously litigious society across 'the pond' takes you to court!