Wow... Ring type lighting circuit!?!?!

[festa]

Hey guys and gals...
Just got back from a call where someones lights were playing up and when tracing the cable (in th`attic) from light to light i found someone (obviously the client denied about doing any DIY), had started from the C.U then wired rose to rose and at the last rose had gone back to the C.U to make the circuit a ring!!!

Has this type of wiring ever been common practice?
Must say i was suprised and double checked it but on driving home it`s really got me thinking

 

[JohnD]

It is not unusual for people in the early stages of learning, once they've understood the ring final, to assume that lighting circuits are done like that too.

If they continue their learning they are generally put right before they start doing installations.

 

[ppuch1]

Just out of curiosity, why is it called a Ring Final and not just a Ring ?

 

[JohnD]

There is also a thing called a Ring Main, which is the supply cable that might run, for example, from a substation up one street, down another, and back to the substation.

 

[ppuch1]

Thanks for the reply,
I understand about the Ring main from the Electricity company - and it does make a clear distinction between these two, but when talking about circuits etc it is normally within the realms of the domestic or commercial environment so I thought calling it a Ring Circuit as you would a Radial Circuit would make better sense.
I was just wondering if it is called such for a definitive reason or if it's just historical.
I had asked many times at college and was never given a good answer.

Thanks again.

 

[JohnD]

I think it's just a way of Electricians being tedious to non-Electricians, like when they say "Bulbs are what you plant in the garden"

 

[jason1958]

If you disconnect one leg of the lighting ring, does the 2-way switching in the hall still work?

One way of doing 2-way switching without 3C+E is to use a second wire for the neutral which returns to the CCU. That was common in the 1950s and the person may have duplicated the layout they found.

It is ok, but should be noted on the CCU.
Nothing in the regs prohibits it, and it is done for very large lighting circuits which this is probably not (EFLI, Vdrop).

 

[RF Lighting]

Just out of curiosity, why is it called a Ring Final and not just a Ring ?

A final circuit is a circuit which leaves the CU to supply a load.

This does not include the likes of distribution circuits.
It is common to have final circuits and non final circuits within an installation.

So really we have ring final circuits, lighting final circuits etc.