Interconnected ring final circuits.

[Risteard]

If its 2 interconnected 32A rings, why was it necessary to down rate to 20A or have I missed something?

If there is an interconnection then one or more legs may potentially be overloaded as it is no longer truly a ring designed not to have excessive load near either end. I wouldn't be happy leaving it on a 32A device in those circumstanes even though it is unlikely to present a problem.

 

[davesparks]

If its 2 interconnected 32A rings, why was it necessary to down rate to 20A or have I missed something?

That would be one hell of a mathematical headache to try and prove that it was safe to put on a 32A supply.
It is a deviation from the standard circuits of bs7671 whatever you do with it so you need to be able to prove that it is safe.

If interconnected rings (within a single circuit, so a figure of 8) were safe on a 32A supply then we wouldn't need to carry out tests to ensure that they don't exist.

 

[polo1]

Risteard & Dave have both set out my reasoning for down-rating the ocpd. Not particularly happy to have all the sockets on a 20A, but it was that or a Code 2:sad_smile:

 

[davesparks]

Risteard & Dave have both set out my reasoning for down-rating the ocpd. Not particularly happy to have all the sockets on a 20A, but it was that or a Code 2:sad_smile:

So what code have you given it now?

 

[polo1]

Code 3 and the interconnection (and the need for 20A ocpd) recorded in the comments section. Did think about no Code, but felt it could (ideally) be improved.
No arguments please - I'm the inspector and coding is at my discretion :boxing_smiley:

 

[davesparks]

Code 3 and the interconnection (and the need for 20A ocpd) recorded in the comments section. Did think about no Code, but felt it could (ideally) be improved.
No arguments please - I'm the inspector and coding is at my discretion :boxing_smiley:

You are the inspector, and your coding is strictly according to the clear guidance of bs7671 I hope.

Why record it in t comments section when that is just a duplicate of the certificate you issued for the alteration to the circuit?

 

[polo1]

Good point Dave. Just belt & braces really. Because it's relatively unusual, I'm keen to make sure those coming after me have a chance of being aware of the issue ( if they bother to read the paperwork); and I think it's relevant to both the EICR & EIC.