Ring final circuit vs Radial final circuit

[Pete999]

Hello mandinga,

the point of a ring final circuit is to use a particular size cable to carry more current than it would if it was a radial circuit. This idea apparentley came about after the 2nd world war. To save on copper wires.

Now the maximum amount of current a 2.5mm T&E is 24 amps. If we are using 2 cables to go to each point of that circuit, then in theory, you can pull twice as much current. Its actually a little less, thats why we use a 32a mcb for a 2.5mm ring circuit not a 40a or 45a. Remember we must always protect the cable from exceeding its current carying capacity.

So 20a mcb for a 2.5mm radial and 32a mcb for a 2.5mm mcb.

Also because the circuit is a ring, the resistance of that circuit is half that of a radial (in theory) and therefore providing a lower r1 + r2.

Hope that helps mate. Sorry, not too great at wording things I want to say.

R1+R2 not r1+r2

 

[Pete999]

I have done some research into this, and from distant memory, the english love of ring mains being able to supply 32A, is to enable us to use "two bar electric fires", just as our Gran had!

I am a strong beliver that the only area that needs 32A ring main is the kitchen / utility. I prefer to fit circuits for bedrooms etc as 16A radials. May need one or two more MCbs.

From memory, we are one of the only countries that still exist on using Ring mains.

Ring Final Circuit, not ring main

 

[driverman]

Ring Final Circuit, not ring main

I'm always guilty of that......old habits die hard.............ring main, ring circuit. been out of the game far too long. I suppose to be 100% correct all circuits are final circuits in a domestic situation.

 

[Pete999]

I'm always guilty of that......old habits die hard.............ring main, ring circuit. been out of the game far too long. I suppose to be 100% correct all circuits are final circuits in a domestic situation.

I'm just a pedantic old git

 

[driverman]

I'm just a pedantic old git

I would of never guessed that!

 

[Risteard]

I suppose to be 100% correct all circuits are final circuits in a domestic situation.

Except if they're not, i.e. distribution circuits.

 

[GMES]

I'm just a pedantic old git

We didn't need it confirming Pete :rofl:

 

[Pete999]

We didn't need it confirming Pete :rofl:

B----r me I 'm on the hit list today am I?:33:

 

[GMES]

B----r me I 'm on the hit list today am I?:33:

Never mate but I knew it would wake you up lol
Besides I am off to work shortly, so I wont be picking on you again till about 6pm!!

 

[Pete999]

Never mate but I knew it would wake you up lol
Besides I am off to work shortly, so I wont be picking on you again till about 6pm!!

Listem Mate with er indoors rattlin my senses all night I had to get up at 05:00 for some peace and quiet, jeez she can certainly put out some zzzzs when she wants to

 

[camerabloke]

I'm just a pedantic old git

No just a git

 

[Pete999]

No just a git

That's just not nice,

 

[telectrix]

at least he left out "old". :8:

 

[camerabloke]

Hahahaha

 

[Pete999]

Suppose that was decent of him, he's still a muppet

 

[camerabloke]

And your still a git

 

[Dan]

Just bumping some threads in the Electrical Wiring Theories and Regulations forum category here on our Electricians Forums. If this specific topic isn't current, just ignore it, it'll drop off the list in no time. However, if it's something you'd like to contribute to, feel free to reply and bring it back into current discussion.

 

[Patrick Powers]

Ring mains are much better for the environment. Radials are wasteful of copper and more besides.

 

[LastManOnline]

Ring mains are much better for the environment. Radials are wasteful of copper and more besides.

Where did you learn that?

 

[Mikegh]

I'm a big fan of the ring circuit in general but I would be in favour of outlawing the ring final circuit in domestic installations

Reason being that it's not a necessity and it would prevent hazardous situations such as breaks in the ring and overcurrent on spurs