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better power cable

A minumum of two things mitigate that possibility , @booja30 : the fused plugtop effectively limiting the max draw locally to something considerably less than one half of the wiring can handle anyway; and what electrical engineers call 'diversity' which is a measure of the way in which practical loading is always rather less than the theoretical. 240Vac/32A is 7.7kW nominal, ==10hp in old money - it's a boatload of power to have on tap nominally for plug-in household appliances! *

- and I an not an EE, and this is not advice ;)

* by which I also mean - if you've got a dedicated high-draw use, a cooker, electric shower- well yes those things are then usu. run on their own dedicated radials, nothing unusual there either. Likewise if you add requirements for say home workshop tools - machine tools , a welder, etc: radials and protection run to suit.
 
Isn't it problematic to have, for example, a device powered somewhere on the ring that depends on the ring topology (e.g. more that 2.5mm^2 of conductor) but there is a fault on the ring? That is to say you could assume all is good since all the receptacles are working, but the ring is actually broken at some point.

I agree wire nuts are terrible (I rewired my house and installed a new panel back in Seattle and still have callouses) and solid core is a PITA to work with in many cramped junction boxes. But I am a fan of radial topology!

I'm a maintenance electrician (Not domestic I might add) from what I hear from mates who do the domestic stuff there's been a big shift from ring mains for this very reason, and the trend now especially in new builds is multiple radial circuits.
 
That's quite a lot. I don't think that you can have many more on a UK 30A ring main that has 2.5mm twin and earth at each end.
 
My house has 10 double, one single, upstairs, on one ring, and 16 downstairs, which has a cooker ring of 30A and one other. I think the UK norm is to put the kitchen sockets, 4 doubles in my case, on the cooker ring as these are generally heavily used for high power items like kettles and toasters. The longer circuit covers the other rooms and these are generally light loads, the lounge for example has lots of appliances but tv's, hifi and lamps are easy. Similarly upstairs, you might have a hairdryer and a heater drawing 8A eac h. That still leaves 14A for a vacuum cleaner, bedside lights, etc.
 
I just checked, there's no limit on the number of sockets! They do suggest no more than 100 sq m floor area to one ring, but that's huge. A family home is generally 100-150 sq m total.
 
I have no doubt this is well out of date now but I think the original regulations said that you could have an unlimited number of 13A sockets on one 30A ring main but the total floor area covered could not be more than 1000 sq feet. I think I also seem to remember that the total number of spurs could not exceed half the total number of sockets on the main ring.
 
There is no limit to the number of sockets allowed on a ring main and the number of points spurred off a ring must not exceed the number of points on the ring.
The 100m² is an accepted rule of thumb. The electrical supplies earthing arrangement, fuse/circuit breaker type and cable conductor size can affect the maximum area that can be served with volt drop and earth fault loop impedance being the limiting factors.
 
I haven't seen the ring circuit before, what is it like for creating magnetic interference (i.e. a big electrified loop of wire around a room)?
 
It is certainly feasible that current on the live and neutral conductors can take different paths around the circuit back to the consumer unit, this could potentially cause EMI issues but it’s not something I have ever encountered.
 
I haven't seen the ring circuit before, what is it like for creating magnetic interference (i.e. a big electrified loop of wire around a room)?
No different to any other form of domestic power wiring- the L/N cores remain v close together, which is always the first line of defence fagainst B-field from AC current: control of loop area the current flows around.

It's got virtually nothing to do with floor plan area.
 
If you have a ring where the current flows along both paths, then you'll tend to get *lower* H-field levels in the middle of the room than if it just went around one side as a spur. 8-] Depends on how anti-symmetric the arrangement may be.
 
Have a look at this (short) presentation/demo form Shunyata Research:


Shunyata make great claim to the idea that their mains cables are all about the science and can be proved to be effective. At the core of the demo Is a bit of true measurement. They measure the impedance of a (particularly) thin power lead and then a thick one (I mean more copper, not just more insulation) - the thicker cable is shown to have a much lower impedance. Now there is no magic or revelation to this and that bit is absolutely true and is scientific ‘fact’. It’s what comes after, all the conclusions drawn, that are questionable. In this vid Shunyata do something very common in the audio world. They take one element of accepted scientific fact and then extrapolate a whole bunch of unsupported ‘reasoning’ and product justification. What Shunyata don’t touch on is whether the lower impedance of the thicker cable* is relevant - can the component it is suppling make use of this aspect; unless it is a large Class A amp drawing lots of current the answer is likely no.

* Any thicker cable would have produced the same result - no need for it to be a Shunyata one.
 
Any 13amp rated cable will do, we're talking a couple of miliohms difference at most. That would equate to an overall voltage drop after the rectifier of sub milivolt levels, 100s of times less than the daily voltage drift due to demand and cycle variance.

It would make zero difference to peak current availability from the caps in the psu, ie no difference to current transient response. £10 says their peak transient measurement doesnt come off the back of the psu boards.

Bad science and half truths.
 


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