New Iberdrola supply – what is the ‘expedient’ builder no.? Favourite This topic contains 0 replies, has 1 voice, and was last updated by Anonymous 7 years, 5 months ago. Author PostsMay 13, 2009 at 8:39 am #54985 AnonymousParticipantI have recently contacted Iberdrola to arrange the initial electricity connection for my new house and they have requested the following:In order to make the new contract we need you to provide us with the “expedient” builder number. You can get this number from the electrician or the builder.Can anyone please explain what this number is and where I could obtain it from i.e. is it on any official paperwork , as I am having difficulty getting a response from the builder.Thanks.Author Posts You must be logged in to reply to this topic.