Final Circuit to Origin?

[Chr!s]

Your adding a new final circuit, so your inspector will be asking the question does it meet the requirements of BS7671.

How have you proved that it meets the requirements for volt drop etc.

Assessment to some degree of the sub circuits will be required unless you have sufficient information to allow otherwise.

Regards Chris

 

[westmac]

I think I am just going to have to make a detailed note on each certificate that I have visually inspected the sub-main circuits the best I can given the constraints of shut downs and access etc.

With reference to regulation 610.1 "Every installation shall, during erection and on completion before being put into service, be inspected and tested to verify, so far as is reasonably practical, that the requirements of the regulations have been met." Could I argue/explain that I have inspected and tested the circuits as far as is reasonably practical by using professional opinion that the sub-main circuits are suitable to use by the final circuit?

The discussion above drifted a little into the origin of supply being the major hurdle, most of this can normally be assertained as said by enquiry. It is mostly the shut down of sub-main circuits which we struggle with.

 

[malcolmsanford]

The bottom line to this is really your call and experience.

If you had a 70mm sub main from a bus bar chamber/ main switch panel going to a TP+N+E DB and the SWA feeding it looked good and on that board there were only 5 final circuits and the highest phase load was 13 amps, and you were asked to fit a new ring final on to it, there is a very good chance that it is not gonig to affect the existing installation so you do the tests on your EIC for your ring final and the Ze if you wish by enquiry.

On the other hand the 70mm is an old SWA, been in use for years, the TP+N+E Db is crammed solid with all sorts on it, with this lone spare way on it, you just manage becasue it is so crowded to clamp a phase, it is jumping all over the place with loads from 50-100 plus amps and they ask you to fit a new circuit, you might want to do a lot more testing and a lot more investigation.

The end of the day it is you that signs things off.