When is a new circuit not a new circuit?

It may not be a new physical circuit as such but I would think it's prudent to treat it as new and consider things like

Supply DB phase rotation

OCPD characteristics.  Maybe the original was wrong or superseded.  Eg Type AC was the norm back then but now Type A or B maybe be correct

volt drop and cable calcs. EG 13amp FCU in a domestic airing cupboard

Diversity

Once done test as you would a new circuit

Label up both ends of the circuit

Make changes to other DB schedule to show circuit was moved

At the end of the day, you were the last person to work on that circuit thus you are now responsible for that entire circuit.

Sergio Fernandez said:

you were the last person to work on that circuit thus you are now responsible for that entire circuit.

I thought the principle was you were responsible for your own work (and the consequences of the changes you make) - which isn't quite the same assuming responsibility for every inch of a circuit that for the most part you haven't touched and probably couldn't even access.

   - Andy.

Sergio Fernandez said:

you were the last person to work on that circuit thus you are now responsible for that entire circuit.

I thought the principle was you were responsible for your own work (and the consequences of the changes you make) - which isn't quite the same assuming responsibility for every inch of a circuit that for the most part you haven't touched and probably couldn't even access.

   - Andy.

I think the idea is your new work should not make things worse than they were before. You cannot reasonably know that all hidden existing cables take routes that you would consider suitable if you had installed it.
Actually in an older building pre the zoned routing rules that came in the 1990s, it probably doesn't !  (14th edition had route things to avoid damage in normal use. Which means different things to different people. 15th edition introduced the 150mm from wall edges and ceilings for concealed wiring. Proper zones and drawings as we know them came with 16th edition and later)

You can however, and probably should, check that the submain Zs or  R1+R2 are sensible, and an IR check, so at least you know nothing is broken or  shorted.

Reasonable steps only are required to confirm suitability, not superhuman effort.

Mike 

AJJewsbury said:

you were the last person to work on that circuit thus you are now responsible for that entire circuit.

I thought the principle was you were responsible for your own work (and the consequences of the changes you make) - which isn't quite the same assuming responsibility for every inch of a circuit that for the most part you haven't touched and probably couldn't even access.

mapj1 said:

You cannot reasonably know that all hidden existing cables take routes that you would consider suitable if you had installed it

Gentlemen, thank you for those thoughts - they help me crystallize my own.

There must be some responsibility for ensuring that the circuit is safe to be connected to the supply, just as for a DB change. However, if you did not install it from end-to-end, it can hardly be "new" even if the board supplying it is new (or relatively new).

To be more specific about the situation, the supply to the house has been re-routed. A new DB has been made ready at the end of the new distribution circuit and this has been notified. The remaining work is to move the final circuits a few inches along the wall.