Ring Or Radial

[hpotter]

One for all the sparkies out there.

I'm proberbly gonna get a rewire done (started with a bathroom fan lol), maybe part, maybe full. Radial ccts there at the mo but think I prefer the ring idea (on a whim, I'd say I prefer 2 routes for earth wire).

Apart from poss cost, what advantages are there to radial?

[satsuma01]

One for all the sparkies out there.

I'm proberbly gonna get a rewire done (started with a bathroom fan lol), maybe part, maybe full. Radial ccts there at the mo but think I prefer the ring idea (on a whim, I'd say I prefer 2 routes for earth wire).

Apart from poss cost, what advantages are there to radial?

the good thing about a radial circuit is the cable can never be overloaded, ie 20 amp trip max 24 on cable rating also alot less cable used generally

[james.wilson]

as sats says if your gonna use 2.5 then you will have to use a lower fuse value. 20A may be enough may not? WOUldnt be for me.

Rings are generally used as they are cheaper to install, personally id go for a ring.

[hpotter]

the good thing about a radial circuit is the cable can never be overloaded, ie 20 amp trip max 24 on cable rating also alot less cable used generally

Thanks for reply.

So why dont all new homes have radial? Thought builders penny pinched etc.

Me too slow on the posting!!

So the additional cost is in the fusebox? Thought this stuff cheap now.

[satsuma01]

Thanks for reply.

So why dont all new homes have radial? Thought builders penny pinched etc.

Me too slow on the posting!!

So the additional cost is in the fusebox? Thought this stuff cheap now.

i wouldnt put a radial in a kitchen if there are lots of appliances as the load would trip the mcb, there is also less things to test on a radial than on a ring circuit.

[hpotter]

I see.

Guess I'll go with ring.

(on a tangent, lighting- if that was radial, one bulb blown, wouldnt take out all lighting?)

[james.wilson]

nowt to do with wiring method.

the reason they sometimes trip is due to the speed a breaker reacts if the filiment failing causes a short in the bulb. It usually does. this then overcurrents.

a fuse doesnt go as it needs a lot of overcurrent for a period of time. see the disconnect times in the regs. but a breaker is very fast.

[satsuma01]

I see.

Guess I'll go with ring.

(on a tangent, lighting- if that was radial, one bulb blown, wouldnt take out all lighting?)

lighting circuits always are radials, but they are wired in parrallel, apart from tampers on alarm installations etc.

nowt to do with wiring method.

the reason they sometimes trip is due to the speed a breaker reacts if the filiment failing causes a short in the bulb. It usually does. this then overcurrents.

a fuse doesnt go as it needs a lot of overcurrent for a period of time. see the disconnect times in the regs. but a breaker is very fast.

also to add a fuse works on a heat basis on the fuse wire where as the trip has a mechanical device wher it is able to detect rather like a computer...

[Woosh]

There is a pile of c##p to be adhered to for the 17th edition a brief synopsos: ( I cant spell)

Unless the wires are:

1 morew than 2" into the wall

2 in steel eatherd conduit

They will have to be protected by an RCD for each circuit generally this requires the use or a MCBO for EACH circuit these cost money trade

[hpotter]

I see.

So an incandecent bulb blowing, the filament (assume h temp -fuse wire) flicks the (say neutral) end which touches nearer than normal phase end giving almost dead short for a fraction of a sec tripping mcb.

Hence ELCB not bothered?

Do low enery bulbs cause mcb trips? (Or 12v lighting for that matter?)

IN my opinion:

Ring for sockets

Radial for dishwasher tumble dryer washing machine cooker immersion heater alarm smoke detectors and lights

Hope this helps.

Kinda what I had in mind. & yes does help. Thanks.