Would adding 2x OCPD (for example 16A MCBs) at this junction point, be seen as a “new circuit”

I'd day definitely a new circuit (or rather two new circuits) - BS 7671 defines a circuit by overcurrent protective devices - as the conductors downstream of the16A MCB would have different overcurrent protection to those before, they'd be new circuits.The assembly containing the MCBs might also be considered a DB or CU - which maybe ticks another box on the notification list.

13A FCUs don't always seem to be treated the same way though, despite BS 7671's definitions...

   - Andy.

vantech said:

I am no longer Part P registered to self notify, and albeit I want to do this myself, I also want to do it properly so if I need to outsource any of this I can (but would much rather not!). 

There is nothing to stop you notifying the Local Authority - before you start the work and paying the fee - and then completing the necessary paperwork.

Thanks for your input. 

What about the new OCPD in the main CU and upgrading this from a 25A to a 40A? New circuit or “modification”?

The 13A FCU debate. To me, an FCU is no different than an MCB, why should one be notified and not the other? Does this mean anyone adding an FCU to a ring final circuit, must notify it? Doubtful this ever happens. 

Why would an MCB be any different, if it’s going in-line with an existing (notified) circuit? 

I think the idea is that putting in an FCU generally involves "fusing down", which is kinda safe-ish, as opposed to the "it keeps tripping so my friend told me I should change the B32 for a C32 or a B40 or whatever", which is less likely to be safe when done by someone with little knowledge or test gear.

Appreciate that, but if done properly in line with the regs the outcome is the same.

Thanks.

Yes looks like this might be the best route - councils tend to charge a fair whack though these days for something that in a commercial or industrial setting, has nothing to do with them! 

Just do it - you are competent to do so.

I am at a loss to understand why changing a 25 A MCB for a 40 A one would be any different from replacing it with another 25 A one.

Strictly speaking, putting in a new DB downstream (or anywhere else) would be notifiable.

Why do you need to upgrade and would 32 A do?

As for reasons for not notifying: my local authority's charges are not available right now, but there would be several hundred reasons for not notifying? ;-)

One other option might be to get an old mate who is still registered to sign it off.

Yeah I am of the same opinion to be honest! 

The 6mm SWA will land into a new DB protected by a new 40A MCB.

There are currently 2 socket radials wired in 4mm SWA. The first radial will remain as a socket circuit on a new 16A RCBO. The second radial will change into a supply for a hot tub, on a 32A RCBO (no sockets on this, just the tub). 

Wiring is pre-existing so want to reuse rather than re-pull! 

I have seen a related trick used as a part P notification avoidance tactic. When the new DB is fitted, there are breakers that do nothing other than supply a short stub of cable, in effect nothing at all, rather than  truly blank ways.

Why ?

Because whatever happens next is just an extension/ modification and not new.  Certainly a replacement breaker is not a new circuit. Adding a new board downstream sort of is, but honestly I'd really not lose a lot of sleep over it - who is it for? - unless it is the sort of situation where someone is likely to report it, I think there is very little to worry about.

A proper job done well but not notified is a lot less concern than a job done badly, or some weird non-notifiable bodge, notified or not.

Mike

The current 2013 gov guidance for part P in England says only the following are notifiable:

• the installation of a new circuit;
• the replacement of a consumer unit; or
• any addition or alteration to existing circuits in a special location.

where "special location" has been cut down to just effectively the zones of 701, plus 702 and 703.

So technically the upgrade to 40A isn't notifiable, the addition of a 25A RCBO should be. But you could argue that you're just messing around inserting extra protection along an existing circuit, so therefore not notifiable.