Russ Andrews alternative

[JohnW2]

In electrical definitions the correct term is ring final.

At risk of being shot down here, 'ring final' is simply a bit of industry jargon (in fact, a sloppy contraction of the proper jargon 'ring final circuit'). Most dictionaries appear to give the meaning of 'ring main' as being what you call a ring final, whereas few dictionaries appear to include 'ring final' (or 'ring final circuit') at all.

If it a ring main then the Oxford English Dictionary states:
"A ring main is an arrangement of pipes forming a closed loop into which steam, water, or sewage may be fed and whose points of draw-off are supplied by flow from two directions. "

True, but what you didn't mention is that it also says:

"an electrical supply serving a series of consumers and returning to the original source, so that each consumer has an alternative path in the event of a failure."

...which is almost there (and, in passing, a supply arrangement which I doubt exists!), and then more-or-less gets there with:

"another term for ring circuit" (which, in turn, it defines as: 'an electric circuit serving a number of outlets, with one circuit breaker in the supply.')

..and the Oxford Advanced Learners' Dictionary says:

an arrangement of cables that allows electricity to be supplied to a series of places from either of two directions

All trades and professions have their jargon, if not almost 'languages ' of their own, which is fine, and I guess that purveyors of ludicrous electrical supplies probably ought to use it - but, as I'm often saying in relation to posters in this forum, one never can or should assume that the general public are in on such things!

Kind Regards, John

 

[Taylortwocities]

I know, John. As a sparky I defer to the BRB and i cannot find any reference to Ring Main, only Ring Final Circuit.

(As you know) I just throw these things in to see how many pedants come to the surface.
Better than being a bottom-feeder, I suppose

 

[stillp]

I know, John. As a sparky I defer to the BRB and i cannot find any reference to Ring Main, only Ring Final Circuit.

That's because a ring main is not a final circuit, and is a common means of supply to a number of consumers, as per John's second definition from the OED!

 

[JohnW2]

I know, John. As a sparky I defer to the BRB and i cannot find any reference to Ring Main, only Ring Final Circuit.

Indeed - but, if we're being pedantic, I suspect you won't find 'ring final' (without 'circuit') in the BRB, either - and that's the phrase one most often sees being used in this forum!!

As you know) I just throw these things in to see how many pedants come to the surface. Better than being a bottom-feeder, I suppose

I'm hardly in a position to criticise that Indeed, as I hinted, in the context of this particular thread, I have no problem with the criticism of someone not using the jargon - it's when Jo Public comes to this forum and gets a bit of stick for talking about 'ring mains', 'plug sockets' etc. etc. that I usually feel inclined to surface!

Kind Regards, John.

 

[JohnW2]

That's because a ring main is ..... a common means of supply to a number of consumers, as per John's second definition from the OED!

Well,as you will have seen, I suggested that such a supply probably didn't exist - so I obviously need some education! I've certainly never seen a domestic installation which has dual supply cables - so are you perhaps saying that consumers are sometimes supplied by 'spurs' off a ring?

Kind Regards, John.

 

[timbim]

Well,as you will have seen, I suggested that such a supply probably didn't exist - so I obviously need some education! I've certainly never seen a domestic installation which has dual supply cables - so are you perhaps saying that consumers are sometimes supplied by 'spurs' off a ring?

Kind Regards, John.

Apparently 11kV lines around cities are often built as rings, but there is always one switch breaking it into what might be thought of as radials. That way, if a line is damaged, the ring can be reconfigured to get a supply to the points that were downstream of the break.

The system is not set up as a ring normally to avoid losses due to eddy currents or some such, or so I believe.

Tim

 

[stillp]

John, from that nice Mr Google:

"Distribution networks are normally formed by interconnecting a number of ring shaped grids. Distribution transformers are then connected to the system by T-offs. Instead of specifying and selecting individual components required for a T-off, the required components are frequently available in an integrated package known as a ring-main unit (RMU).

Ring-main units normally consist of switches on both sides of the T-off, one to open the ring and another at the connection to the distribution transformer using one of the following:

- Switch and a fuse separately
- Switch-fuse combination"

 

[JohnW2]

John, from that nice Mr Google:
"Distribution networks are normally formed by interconnecting a number of ring shaped grids. Distribution transformers are then connected to the system by T-offs....."

That much I did think I knew, but that's all HV, and very few domestic consumers have their own transformer. I was thinking of the LV distribution, which presumably is not arranged in rings?

Kind Regards, John

 

[stillp]

Ah, now you've sneaked that word "domestic" in!

I believe there are such things as LV RMUs, but could be wrong.
I'm sure one of the DNO contributors to this forum will be along shortly to explain

 

[JohnW2]

Ah, now you've sneaked that word "domestic" in!

Not really, it was there in the last of my messages to which you replied:

I've certainly never seen a domestic installation which has dual supply cables - so are you perhaps saying that consumers are sometimes supplied by 'spurs' off a ring?

I believe there are such things as LV RMUs, but could be wrong. I'm sure one of the DNO contributors to this forum will be along shortly to explain

OK - I wait for the continuation of my education. I do, however, rather doubt that any domestic consumers are supplied via their own 'spur' off an LV 'ring main' - but maybe I'm wrong!

Kind Regards, John.

 

[Stoday]

The nearest approximation to an LV distribution ring is the circuits that link substations. These are often incorporated into distribution systems so that supplies can be maintained during substation maintanance.

Normally the circuit also supplies consumers and has manually disconnectable links so that it can feed various parts from different substations. Two substations are never connected; one link is always open. Except in London where everything is (I'm told) linked up solid.

 

[JohnW2]

The nearest approximation to an LV distribution ring is the circuits that link substations. .....

Thanks for clarification.

Kind Regards, John.

 

[securespark]

But my current favourite is this:
http://www.russandrews.com/product....&customer_id=PAA0405071911383CTCEECOKLIPHFMNV

This is good too. What a price!

http://www.russandrews.com/product....&customer_id=PAA0405071911383CTCEECOKLIPHFMNV

It's not 4mm2, btw, it's 2.5...

 

[Stoday]

You can't say that Russ Andrews is expensive when the 2.5mm² G/Y single core is more expensive at B&Q.

 

[Paul_C]

It's not 4mm2, btw, it's 2.5...

And according to the blurb, it's 2.5 sq. mm "cross sectional diameter."