Ring final & Radial circuits off one mcb ?

[Soulsurfer]

Another straight forward job today has turned out to be a right mess once again so I thought I'd get some thoughts on the following before I start !

So an old MK LN59 board, feed to garage sockets on a single 2.5mm t&e from a 15A mcb and also spurred to feed a boiler on S plan,

Next ring final on a 30A feeding upstairs sockets as usual but on cover removal I found a 4mm t&e spurred from same 30A mcb and feeding opposite side of garage to sockets all on the 4mm then at the end spurred from last socket with 2.5mm t&e to feed new water cylinder via a DP switch !

Obviously I'm not happy with the 4mm being spurred as an extra circuit from a separate circuit pd but surely the immersion being spurred from sockets is rough too ?

Never seen anything like that before !

 

[davesparks]

Whilst it's a bit of a bodge I suspect you'd be hard pressed to find anything that strictly doesn't comply with 7671.

It's not two circuits, it is all one circuit as it is all fed from one ocpd

 

[Soulsurfer]

Fair comment, was just thinking as there is virtually no load on upstairs rfc there could be an option to swap around ocpd's to make the upstairs ring run from a downgraded 20A and use the 3oA for the sockets on one side of garage as he wants to add 2 x more sockets in garden rcd protected. But really I'll need to try persuade him also to get a separate new cable out for the immersion element in its on right.

 

[westward10]

Two final circuits in my opinion.

 

[ChrisElectrical88]

Two outgoing final circuits but classed as one circuit cause they come out of the same PD. Madness but how it is.

 

[Octopus]

Sounds like creative use of the regs to use a single mcb in a sensible way.....

 

[westward10]

Doubt there was creativity about it, ooh where shall I put this new circuit, ah yes whack it on the ring. Dress it as you will.

 

[Risteard]

Two outgoing final circuits

By definition it is definitely only one final circuit.

My only concern would be with the mix of 4mm^2 and 2.5mm^2 conductors that they are all securely clamped at the protective device.

 

[davesparks]

Two final circuits in my opinion.

But not by the definition in bs7671

 

[saspm]

By the sounds of it all the cables are all protected correctly. But like you say, bit of a bodge!

 

[Soulsurfer]

Time to find another old mcb on eBay then, and start seperating up properly.

 

[westward10]

But not by the definition in bs7671

I disagree but that is my interpretation of the Regulations.

 

[davesparks]

I disagree but that is my interpretation of the Regulations.

a circuit is defined in 7671 as 'an assembly of electrical equipment supplied from the same origin and protected against overcurrent by the same protective device(s)'
How do you interpret this as meaning that multiple cables connected to the same protective device are anything other than one circuit?

 

[westward10]

We've been there before on this Dave my view won't change.

 

[David M]

a circuit is defined in 7671 as 'an assembly of electrical equipment supplied from the same origin and protected against overcurrent by the same protective device(s)'
How do you interpret this as meaning that multiple cables connected to the same protective device are anything other than one circuit?

Though the interpretation is such, I think its a bit daft. I've often come across one mcb protecting a number of "different" circuits. Tested them and recorded them as individual which to me makes sense (I could be completely wrong of course), even though I'm well within the regs to just record the highest readings of which ever "circuit" produces them.

 

[Octopus]

We've been there before on this Dave my view won't change.

Not taking sides but I do agree with Dave!

At the end of the day you turn off 1 circuit breaker to isolate both cables... So that makes it 1 circuit.

If this is an EICR then it would be C3 with a recommendation to separate them out, space in the CU allowing

 

[westward10]

Not taking sides but I do agree with Dave!

At the end of the day you turn off 1 circuit breaker to isolate both cables... So that makes it 1 circuit.

If this is an EICR then it would be C3 with a recommendation to separate them out, space in the CU allowing

That is interesting that you C3 it as I do the same. Out of further interest how do you word it on the EICR.

 

[Octopus]

^^ word what?

 

[westward10]

^^ word what?

How you actually word the multiple circuits, or cables at one device on the Report recommendations.

 

[Ian1981]

Perhaps regulation 314.4 which calls for more than one final circuit to be connected to a separate way in a distribution board.
It may be that by definition it's one circuit but it's clear that there where no spare ways in the db so it just got shot in with a ring final circuit.
Admittedly it perhaps doesn't go against regulations