Dedicated Radial Plan

I can’t see any issues with that, however keen to know what size cables he is using, and what size rcbo’s. For HiFi, people go either 6mm or 10mm. If he is doing anything less, then in my opinion I wouldn’t go ahead if you want close to the best.

Was there a reason he wouldn’t go directly from the outside meter? Or was it just convenience.

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I asked for 10mm T&E.

(I will probably ask him to get Doncaster Cables T&E, unless anyone else or he tells me some other make of T&E is likely to be better - although I did not discuss this with him on today’s first meeting.)

He did originally say he’d take the meter tails straight through the wall into the front left corner of the listening room and add a CU there, but I mentioned that I have speakers, crossovers and speaker cables that need to be right next to that wall, so we agreed that would not work.

We didn’t discuss the outside route in detail - but the problem with that if I’m having 6 x 10mm SWA cables is that they would have to be routed over the gas meter, which is more cable and would be visible from some angles from the front of the house, which is becoming an eyesore, and then there’s the issue of possible water ingress into the mounting box as the storms slam into the house over the coming decades.

Thus routing it from the house mains ring CU and along the right hand wall into the front right corner seems best.

This that not right where the 25mm cable enters the property - but how much difference will that make?

Also, what route will the earth take back to the meter earth?

Mcru has various cables, sockets etc which might be worth a look before you take the plunge.

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So your earth from the New CU will be shared, and possibly taken from the old CU. A possible improvement might be to ensure the earth goes to an earth block, and then you take two feeds off that for each CU. Perhaps he would do that anyway, but worth confirming.

I think it is @ChrisSU amongst others that suggested one 10mm radial is better than multiple runs. No doubt others will disagree. Of course you then need a Mains Block, but that does ensure all the earth wires are exactly the same length - how much that matters, who can accurately say without lots of discussion and heresy.

I just checked ChrisSU’s 8 posts in this thread and he does not say that 1 radial/socket is better than multiple radials/sockets in those posts that I can see.

My decision is whether to go for 6 radials into 6 sockets and then have 6 Powerlines to my 6 IECs, which gives isolation of the lines and is less expensive?

Or 1 radial/socket and then a ‘block and Powerlines’ or a very good Hydra - where I could make the radial from posher materials but the whole thing is even more expensive and there are more junctions and components in the chains and it could get a lot more expensive and the cable dressing might be harder to control?

These 2 topologies are the extremes of ‘less’ vs ‘more’ and there are lots of other variants in between.

You might consider quality vs quantity. 10mm perhaps a good hedge for bog standard cable but I don’t know of any “audiophile” in wall cables that are bigger than 4 or 5mm. Given the deep pockets of “audiophiles”, that’s a surprise unless there really is no benefit vs smaller, higher purity copper and more advanced constructions.

Yes, that’s exactly what I discuss in the above post that I wrote as you wrote your post.

One aspect of this is how much I should spend on the in-wall cable from CU to sockets vs on the final cables from sockets to Naim boxes?

(And how much on the sockets themselves?)

As a general principle I think I should prioritise the final cables from sockets to Naim boxes a lot more than the in-wall cable, which is one step removed.

Getting a good fat copper in-wall cable seems sensible - and going from one Powerline currently (plus a Graham’s Hydra and one other cable) to all Naim Powerlines seems like a sensible way to stick to excellent Naim cables within a reasonable budget.

This prioritises isolation of the radials over the ‘Hydra effect’.

As I cannot actually test these 2 options I’ll never know which would have been best.

But my recent experience with a Powerigel hydra (not made of Powerlines) that didn’t work well in my old system has pushed me away from the hydra option in the end.

Getting multipack radials at least gives you choice at not too great a cost

I didn’t mean single vs multiple runs, I was referring to the size and quality of the cable in the run(s). Regular 10mm T&E vs say 3mm OFC with an audio considered construction. There are lots of in wall cables on the market designed for audio installations, I don’t know of any that are 10mm.

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Yes, but in my budget constrained world I can buy 40m metres of 10mm T&E and have 6 radials for a lot less than 6m of much thinner Furutech OFC in-wall cable for 1 radial.

And the Furutech in-wall might not make sense in my system until I have much better IEC leads, etc.

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Got you. Was just wondering if you had considered it, clearly you have :+1:

Hi @JimDog – I must have missed something in this continuing project, as I thought the cabling had all been sorted - obviously not (perhaps need to pay closer attention :grinning: ). Some thoughts:

1- I’ve been advised that single 10mm radial in to a quality block is better than 6 radials from a dedicated CU – but, TBH, I’ve not been able to do this in my own home (yet!).
2- have you considered the Gigabit breakers, which seem to offer an improvement (if I’ve read other threads correctly?).
3- the thing about the dedicated CU is to:
a- get improved earthing and away from any ‘noise’, ideally dedicated earthing arrangements if these are possible (depends on the house’s wiring set-up).
b- ensure, as best possible, the bus bars in the CU offer the best feeds to the radials, which means (ideally) having 2 bus bars – if you have one, then (AFAIK) the radials will pick up solely ‘in series’, hence why one radial + (star-wired?) block is considered better(?)

Above said, it seems star wiring has been eschewed by the likes of Chord in their latest blocks, which appear to have 2/3 bus bars, one for each cable?

Obviously, if you’ve been diverted per your experience with the Powerigel, then fair enough. Overtly, using the likes of a Chord block is very expensive, especially when one includes the power cable to this (which is non-standard 16A IIRC).

To be honest, I went one direction many years ago and simply now live with it (vis 6 radials), as it’s too messy to muck about with sockets/blocks et al.

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Yes, I have considered the Gigabit, Siemens and/or Dopke breakers but that itself is costly before you even start on the rest of the circuits and the IEC leads.

Are your radials 10mm T&E (I forgot) and are you happy with them?

Thanks - that’s a great reminder about the 2 busbars - is that what your CU has?

I have PME earthing system and I discussed improving the earth with the electrician but we did not reach a conclusion as to whether this is do-able in my house.

Do you have Powerlines to the Naim gear?

I cannot speak too much about my set-up, as while my qualified sparks was happy with it (just about!), I’m not sure how it plays to regs now. FYI, back about 20 years ago, there were some parties on the Forum who had experimented with differing wiring options, and their guidance was shared – I have to stop here.

I have a dedicated MEM CU (sadly single bus bar), with 6 x 10mm radials (with high-rated RCBOs) – fortunately, the CU is on the other side of the wall, in the garage i.e. very easy wiring dropped through a cavity wall. Henley block is split with hi-fi CU ‘first’, with dedicated earthing.

I use Powerlines x 6. Having vinyl and CD sources, I very nearly needed a 7th feed some time back but managed to compromise.

I’ve often wondered about going the block route, which may come about but…it’s hassle and cost, and not an easy experiment to conduct IMV.


The thing is some of the practices that actually improve our hifi sound don’t comply with regs. One example would be fitting a dedicated earth (via spikes) for the hifi supply to a utility PME system which has earth bonded to neutral. Although not likely to cause an issue in real world situations they just might. With spikes installed our home could become the source of earthing for everyone on the same grid should certain faults occur somewhere along it. Likely? No. Impossible? No. I prefer 15amp fuseless mains plugs and sockets but again they don’t comply with regs.

So even if they aren’t likely to be dangerous per se our insurers would not be sympathetic if in the unlikely event these “alterations” were revealed during a relevant claim. A fundamental grasp of AC is very helpful then apply common sense.

Agree – noting (AFAIK) one isn’t allowed to alter internal wiring nowadays unless under the gaze of a qualified sparks. The PME aspect has been raised several times.

And one can find things out when not expecting them sometimes. Having bought a pre-loved MF Dr. Thomas & Pre-Amp many years back, I surprised at what was occupying the fuse slot in the plugs…and there was a lot of solder in sight too. Yikes.


You can elect to have just your own earth for all your house requirements (called TT I think), but think then you have to ensure those spike locations are well watered to ensure the connection to earth doesn’t dry out. I must add I have no experience of this, but understand that some Radio Hams use this method.

Don’t think you can safely mix a TT system with PME


That’s just what I wrote. We can’t mix the two . TT systems are seldom found now as they have been phased out. Usually only found in certain houses in rural areas


Naim advised me years ago that a single 100mm cable and then a hydra or block will give a more together sound than multiple radials. Having six SWA cables, which are massive, seems like a slightly potty idea and will look awful.

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OK - I didn’t realise Naim had been advising that.

I have been on the fence between the one radial and the 6 radial options for weeks as I have been trying to understand how these circuits work and what they can be made from.

Those responses nudge me quite strongly towards the single radial option.

That would look a lot better and would mean I would spend less on labour and quantities of parts, so could stretch to quite a good cable and a posh socket (and matching plug) too.