Radials V Ring mains

[Sparky10]

Hi all,

This may be a common topic and may already have been spoken about 100s of times so forgive me in advance.

I have always wired in ring mains for my sockets up until recently..

I came across an install where all sockets were wired in 2.5 radials protected by 20A RCBO they had wired 3 bedrooms all on separate 2.5 radials (Loft & 1st floor)
i did question why each room was separate and the response i got was "customers request due to computers"

I am hearing more and more people wiring 4mm radials protected by 32A as its "convenient"

whats peoples general thoughts on this?

 

[buzzlightyear]

I am hearing more and more people wiring 4mm radials protected by 32A as its "convenient"

I can understand if a couple of sockets covered by a 20amp, but a full floor would be a ring .
but it down to the installer what he thinks at the time .

 

[Sparky10]

Each room is on a separate radial with around 4 sockets in - very weird arrangement i know

 

[Spoon]

Hi all,

This may be a common topic and may already have been spoken about 100s of times so forgive me in advance.

I have always wired in ring mains for my sockets up until recently..

I came across an install where all sockets were wired in 2.5 radials protected by 20A RCBO they had wired 3 bedrooms all on separate 2.5 radials (Loft & 1st floor)
i did question why each room was separate and the response i got was "customers request due to computers"

I am hearing more and more people wiring 4mm radials protected by 32A as its "convenient"

whats peoples general thoughts on this?

Great idea.
20A is plenty for a bedroom and when the kids don't get off the consoles you can switch off the mains to their bedroom.

 

[Sparky10]

Haha! i never looked at it that way - No more fortnight for my son if i had this wiring arrangement

 

[Silly Sausage]

More circuits, more cash ... Kerching!

 

[Wilko]

I would struggle to guarantee 4mm radial was ok for 32A MCB, just saying.

 

[Sparky10]

I would struggle to guarantee 4mm radial was ok for 32A MCB, just saying.

would also struggle getting them into back of sockets too

 

[mhar]

I would struggle to guarantee 4mm radial was ok for 32A MCB, just saying.

I wouldn't do it either, now on a 25A is something I regularly do

 

[Strima]

Each type of circuit has its merits, whatever suits the need of the installation and the client.

 

[Pete999]

would also struggle getting them into back of sockets too

Had no trouble so far.

 

[Sparky10]

Had no trouble so far.

never dealt with it just making silly assumptions... guess im wrong

 

[Sparky10]

Had no trouble so far.

Take it you do 4mm Radials?

 

[Pete999]

Take it you do 4mm Radials?

Not any more Sparky 10, as I have been retired for a few years, but to answer your question, yes I did, but always in conjunction with the restraints and the advice in Appendix 15 BS7671, floor area etc.
I also ran 6mm radials whilst working in Canada @110Volts using MK 110V socket outlets, had nil trouble with connecting them up either. Just saying.

 

[Pete999]

Not any more Sparky 10, as I have been retired for a few years, but to answer your question, yes I did, but always in conjunction with the restraints and the advice in Appendix 15 BS7671, floor area etc.
I also ran 6mm radials whilst working in Canada @110Volts using MK 110V socket outlets, had nil trouble with connecting them up either. Just saying.

Just to be a Pedant they are not Ring Mains any more they are Ring Final Circuits or RFCs

 

[Octopus]

Give the customer the choice , the prices and the pros and cons and let them decide

 

[buzzlightyear]

I also ran 6mm radials whilst working in Canada @110Volts using MK 110V socket outlets, had nil trouble with connecting them up either

that was the old MK sockets put in them days ,try the new ones ,then you will struggle .

 

[Pete999]

that was the old MK sockets put in them days ,try the new ones ,then you will struggle .

Within the last 10 years Buzz

 

[buzzlightyear]

Within the last 100years Buzz

 

[Baddegg]

Great idea.
20A is plenty for a bedroom and when the kids don't get off the consoles you can switch off the mains to their bedroom.

Have rewired a house before with that exact request for that reason...

 

[Nigel]

All we do is 4mm radials. Easier to wire and less testing.

 

[GeorgeCooke]

I also ran 6mm radials whilst working in Canada @110Volts using MK 110V socket outlets, had nil trouble with connecting them up either. Just saying.

I cannot understand how someone can be working on electrics in Canada and not know the voltage is 120v plus or minus 5%. 110v is a myth and outside the permitted tolerance.

 

[garyt]

I cannot understand how someone can be working on electrics in Canada and not know the voltage is 120v plus or minus 5%. 110v is a myth and outside the permitted tolerance.

Hi check regulations , can use radial 2.5 mm serves 50 square meters 20 amp cb& 4mm at 75 square meters 32 amp cb

 

[ipf]

Just to be a Pedant they are not Ring Mains any more they are Ring Final Circuits or RFCs

Just to be even more pedantic.....and being sick to death of this subject...….I'd go for radial, 1.0mm T+E, 5 amp 3036 and a row of 5amp sockets....

 

[Simon47]

If you think about it, if you take an RFC wired in 2.5 and supplied by a 32A MCB and: remove one section of cable, and split the tails across two 20 or 25A MCBs then you have :

• Increased the total available current from 32A to 40 or 50A
• Reduced the amount of cable used

So the two radials (assuming a new install or a rewire) will need less cable and provide a higher total load capacity than the same outlets wired as an RFC. You've also (assuming RCBOs) reduced the amount of stuff that goes off when a breaker trips.
However, you've also increased the volt drops. So if the alternative RFC was on (or near) the limits, the two radials would most likely be over the limits for volt drops.