Extending a Ring Circuit

[JohnW2]

The regulation does not state "unless some people argue..." Some people argue the world is flat.

All true - but you're taking my word "argue" in a different sense from what I intended, so lets try again ...

"Some people may hold, and attempt to promote, the view that a reversible plug/socket represents a 'less degree of safety' than does a non-reversible one"

Kind Regards, John

 

[EFLImpudence]

"Some people may hold, and attempt to promote, the view that a reversible plug/socket represents a 'less degree of safety' than does a non-reversible one"

...but where they are installed as they should be, they do not.

 

[ericmark]

The regulation does not state "unless some people argue..."

Some people argue the world is flat.

Terry was a safety officer before he wrote disc world.

However BS 7671 is some times hard to decide if the ambiguity is intentional or not.

It is easy to say I will not load a circuit in that way, but as to anyone in the future, that is something else.

BS 7671 is not law, and unless some one is injured no one is really interested. And the thread is not about using silly German sockets, so that debate should be a diffrent thread.

 

[JohnW2]

...but where they are installed as they should be, they do not.

I'm not taking sides (either way) merely pointing out what view/belief/judgement some people have.

One of the problems with anything to do with sockets, or sockets circuits, is that neither designer nor installer can ever know what might be 'plugged in' in the future - designers need to keep that uncertainty in mind.

Kind Regards, John

 

[plugwash]

One of the problems with anything to do with sockets, or sockets circuits, is that neither designer nor installer can ever know what might be 'plugged in' in the future - designers need to keep that uncertainty in mind.

Absoloutely.

There certainly exist appliances which are less-safe when connected with reverse polarity than connected with correct polarity.

OTOH I've seen way too many Schuko plugs over the years connected to UK mains in an unsafe manner, either manually opening the shutters and forcing the plug in, or using an unsuitable adapter that does not maintain the earth connection (and may or may not be fused, and may or may not be a "direct from china" peice of junk).

So I suspect providing Schuko sockets (with appropriate overcurrent and RCD protection) in addition to the BS1363 sockets in areas that foreigners are likely to plug in equipment is likely to improve safety overall. OTOH I would expect fitting them instead of the BS1363 sockets to reduce safety.

French sockets are pysically non-reversable, but there seems to be no consensus as to the correct way round to wire them, so in practice they may as well be reversible.

 

[JohnW2]

Absoloutely. There certainly exist appliances which are less-safe when connected with reverse polarity than connected with correct polarity.

That is obviously the view of the people I was referring to. However, as you go on to say, there are some swings and roundabouts involved ...

OTOH I've seen way too many Schuko plugs over the years connected to UK mains in an unsafe manner ..... So I suspect providing Schuko sockets (with appropriate overcurrent and RCD protection) in addition to the BS1363 sockets in areas that foreigners are likely to plug in equipment is likely to improve safety overall. OTOH I would expect fitting them instead of the BS1363 sockets to reduce safety.

I don't disagree with any of that, but I think that the pendulum only swings in the pro-Schuko (Schuko and BS1363) direction if the area is such that it really is "likely" that "foreigners will plug in equipment - and I agree that only in very exceptional circumstances would having only Schuko sockets (in the UK) probably not reduce safety (i.e. it probably usually would reduce safety).

French sockets are pysically non-reversable, but there seems to be no consensus as to the correct way round to wire them, so in practice they may as well be reversible.

... well, they are "foreigners"

Kind Regards, John

 

[Jupiter01]

Another thought...
As an alternative, could I also create a new ring using 2.5mm cable and wire this into the exiting 32amp Breaker? This would mean that the existing breaker is then protecting two rings. I assume nuisance tripping will be a consideration but the reality is that we have very few sockets and will not be exceeding 32amps across both Rings. The cables provide the necessary protection in both cases and the breaker is sized appropriately.

This may be an attractive option as the consumer unit is not very far from the location of the new sockets. I suppose a new radial with 4mm T&E is also an option?

Thanks for your support

 

[winston1]

French sockets are pysically non-reversable, but there seems to be no consensus as to the correct way round to wire them, so in practice they may as well be reversible.

They are Belgium sockets that France decided to adopt. But, I digress, for a long time there was no consensus which way to wire them (indeed double sockets often had each one different). But now in France and Belgium the live should be clockwise from the earth looking at the socket front. Trouble in Slovakia and the Czech Republic the standard is the opposite. Don't know which way round is standard in Poland.

 

[Taylortwocities]

Another thought...
As an alternative, could I also create a new ring using 2.5mm cable and wire this into the exiting 32amp Breaker? This would mean that the existing breaker is then protecting two rings. I assume nuisance tripping will be a consideration but the reality is that we have very few sockets and will not be exceeding 32amps across both Rings. The cables provide the necessary protection in both cases and the breaker is sized appropriately.

This may be an attractive option as the consumer unit is not very far from the location of the new sockets. I suppose a new radial with 4mm T&E is also an option?

Thanks for your support

NO!.
To start with, how would you fill in the installation certificate. Which Zs would you choose, the old ring final, or the new one. How would you carry out ring continuity. Pick one from 4, then try and find its friend? Ridiculous.

By all means add to the EXISTING ring final at the consumer unit. To do this EXTEND the ring by removing one leg of the ring. (L&N).
Connect up new cable to your new sockets which are connected in series (as a ring). And then bring the return leg back to the MCB. Then you have just two conductors in the MCB, as you should have.

If you only want one cable from the MCB then it would be a spur, you'd then need a 13A FCU before any of your additional 4 sockets.

 

[JohnW2]

NO!.

That was my first intuitive reaction, and probably that of most others.

However, when I thought, I could think of no way in which it would be non-compliant or in any way 'unsafe'. All the circuits/cables are as well protected as they would be with a single ring, and the situation is not really conceptually much different from having two radials (or 'branches of a radial') originating at the CU, or an unfused spur from a ring final originating at the CU.

As you go on to say ...

To start with, how would you fill in the installation certificate. Which Zs would you choose, the old ring final, or the new one. How would you carry out ring continuity. Pick one from 4, then try and find its friend? Ridiculous.

That's all true, but they are all matters of 'convenience', not safety, and all relate only to 'testing'. With a little fiddling, one could ascertain 'which conductor was which', and the Schedule associated with the EIC (or an EICR) could easily be 'adapted'- probably simply by include a second row of results for the OPD in question. Indeed, were it not for BS7671's definition of 'a circuit', one could simply document it as two circuits.

I'm certainly not advocating the practice but thought I should point out that it would probably be 'compliant' (unless someone can correct me) and 'safe'.

Kind Regards, John

 

[Jupiter01]

By all means add to the EXISTING ring final at the consumer unit. To do this EXTEND the ring by removing one leg of the ring. (L&N).
Connect up new cable to your new sockets which are connected in series (as a ring). And then bring the return leg back to the MCB. Then you have just two conductors in the MCB, as you should have.

I assume that it is implied in the above but you would need to connect the new sockets to the existing sockets to ensure that there is continuity between the two legs at the CU: one new and one old.

 

[JohnW2]

I assume that it is implied in the above but you would need to connect the new sockets to the existing sockets to ensure that there is continuity between the two legs at the CU: one new and one old.

That's what TTC said. It's really no different from 'extending the ring' anywhere else - one can 'extend' it by adding additional sockets between two existing sockets, OR by adding additional sockets between CU and the first or last socket on the ring.

Kind Regards, John

 

[Jupiter01]

That's what TTC said. It's really no different from 'extending the ring' anywhere else - one can 'extend' it by adding additional sockets between two existing sockets, OR by adding additional sockets between CU and the first or last socket on the ring.

Kind Regards, John

I thought so but the part on connecting the old and new sockets wasn't clear to me and clearly without that, we wouldn't have a complete ring.

 

[winston1]

Connect up new cable to your new sockets which are connected in series (as a ring).

They would not be in series as in L of one to the N of the next etc. They would be in parallel on a ring.

 

[JohnW2]

Sigh