why not make all circuits radial?

[44ALLAN]

Because you dont want it to trip do you?
Just imagine Ms Jones trying to cook her family christmas dinner with the kettle on and god knows what else.
Sure the appliances are fine but if you have a 20A radial and you exceed that and trip the breaker she aint going to be happy.

Yup that's why we put correctly sized ocpd's/mcb's etc on the circuits surely?
If some daft tXXZ has put a 12kw cooker on a 20amp radial then...............yup your right.............it will trip during xmas dinner especially when they plug the 3kw heater into the cooker 3 pin socket !!!!

Circuits should be designed to stop that happening mate........................if someone then decides to plug 3 extension cables into a 13 amp socket with 3 kw heaters plugged in then that's their prob.........13amp fuse would soon pop tho)

 

[Tiny Spark]

12kw I think would be a bit much...
I was thinking more like a 3kw oven, maybe a 3kw heater it wouldn't be unheard of.
We had one in our old house as no central heating in the kitchen and the water pipes would freeze in winter.

Oh wait thats just tripped my 20A MCB and I never even got around to making a cuppa for uncle joe!

You are right, circuits should be designed for the loads you would expect on them.

I expect a heavy loading in a kitchen so would put a ring in.
I dont expect heavy loading in a bedroom so radial would normally suffice.

At the end of the day you have to wire a system with the customer in mind.

If its a small kitchen with central heating and a gas oven then a radial would prob do.
If its like my old kitchen as described above then it probably aint.

Everything has to be considered.

That being said I always prefer a ring for the extra flexibility it brings but thats just my opinion.

 

[44ALLAN]

I agree that's why I responded in post 27 .

Nowt wrong with a 20amp radial feeding a 3kw heater.
If they decide to then plug in 3 extensions and 3 more heaters it ain't your problem mate............simple

 

[curtiselec]

can do all required testing without leaving consumer unit and going looking for last point.
20amps for a 2.5radial is sometimes not enough (4800watts) = kettle + toaster + washing machine in the kitechen at same time and the thing will trip.

quite a useful invention

Less testing is always good!

 

[dan86]

Less testing is always good!

don't entirely agree with that. testing and fault finding can be worth a good bit of a days wage!

 

[delano]

Well you wouldn't use 2.5mm, you'd use 4mm.

 

[Tiny Spark]

I agree that's why I responded in post 27 .

Nowt wrong with a 20amp radial feeding a 3kw heater.
If they decide to then plug in 3 extensions and 3 more heaters it ain't your problem mate............simple

That does just come down to stupidity and lack of education.
But its easily done and pretty common unfortunately :s

 

[nickblake]

Ive just done a EICR on a property and found a 6kw connected to the ring main via a 20amp switch , its length of the run if you have a 2.5mm radial then its easy to get up to the maximum Zs on longer runs 4mm radials are ok use them my self but for lower Zs readings a ring is best just my opinion

 

[Octopus]

A few weeks back I went to investigate a "multiple" MCB tripping on a board.

House built in early 1970's, 3036 board with I suspect, customer installed MCB's.

After a bit of testing I could see that the 2 rings were connected to a pair of 15A MCB's - each ring having both legs in different MCB's....... so a swap to correct wiring into the CU and an upgrade to 30A MCB's and the things held.

The trippping occurred every time that they boiled the kettle and used the washing machine!!

Now a happy customer and they had lived there for about 30 years!

 

[richy3333]

Inspected and tested a new build last week that the customer had wired up themselves - everything is a ring - sockets, lights, cooker, everything! Wholesalers best friend

 

[Geordie Spark]

How about a more relevant question. Why in the UK, do we allow under qualified, ill trained, inexperienced people into peoples homes to carry out electrical work that they don't fully understand??

I'm not doing it anymore ....... I'm retired.

 

[ackbarthestar]

Inspected and tested a new build last week that the customer had wired up themselves - everything is a ring - sockets, lights, cooker, everything! Wholesalers best friend

Presumably, DIY or over enthusiastic apprentice. Did you count the number of clips?

I saw a job once, where every cable, undressed, emanating from the DB had been over-clipped (100mm apart). Would have looked better if no clips were used at all.

 

[Tiny Spark]

Inspected and tested a new build last week that the customer had wired up themselves - everything is a ring - sockets, lights, cooker, everything! Wholesalers best friend

Cooker had its own ring???

Dang!!

Did they have a electric shower?

 

[oldtimer]

This post should have been titled Do we need the ring circuit anymore and yep because a lot of appliances are low current it sounds good until your in the kitchen fine run radials but now we need bigger CUs

 

[odawire]

can do all required testing without leaving consumer unit and going looking for last point.
20amps for a 2.5radial is sometimes not enough (4800watts) = kettle + toaster + washing machine in the kitechen at same time and the thing will trip.

quite a useful invention

If you have 2 radials feeding a kitchen, ie 1 for the sockets and 1 for the appliances, you use less cable then 1 ring.