Dedicated radial circuits

You could do and just daisy chain them with smaller gauge cable. You could also go the single socket and Grahams Hydra / Music works block which some prefer.

As you can see from the thread, there are a few different approaches for different needs and preferences. I’d work out what kit you need to power (now and future requirements) and decide from there.

Whatever socket arrangement you choose it’ll still be better than sharing a ring with a lot of different household electrical items. Our plasma TV used to share the same ring as the Hi-Fi and had quite a detrimental effect. No problem with music (TV off) but we use the Hi-Fi for TV and Movie sound. With the HI-Fi on the radial, no issues anymore.


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Thanks, HH. Sage counsel. Will do.

Hi Debs, I wasn’t on the Forum when mine got put in so I took advice from a customer of my dealer who happened to be an electrical contractor and had tried quite a few types of cable. He recommended CY which is shielded. My installation is 4mm without dedicated CU! It runs round the outside in conduit mostly so it doesn’t pick up noice from inside.

I did succumb to PowerLines everywhere and the MusicWorks with sparkly base. The right arrangement of plugs and regular contact cleaning makes a difference. Life is too short to try all the combinations!



My electrician is doing me a dedicated radial today as we needed our boards sorted out anyway.

Should be a step up from the separate spur I already had…let’s see.


Hi All,

I am a sparky!!! Yes, I really did say that, and I wired a single 6mm radial circuit (not a spur) from a dedicated small RCD protected consumer unit (made by Hager which seem to be good and solid units to me) for my Naim system! It made a massive difference. This cable powers three twin sockets which, somehow, I managed to get all the wires in to (it was a struggle). The main problem with 10mm cable is a practical one rather than theoretical - you cannot get more than one 10mm cable in to the terminals on a socket, so, you either have three separate radials or just the one. Personally I don`t think the extra cost (especially in houses where it is difficult to install the cables) of three radials is worth it. I actually used armoured cable rather than twin and earth which, to my mind, has the advantage of having an earth conductor the same size as the line and neutral conductors. It also has steel armouring that may or may not help to reduce RF interference. Again, the main problems are practical but if you can do it, do it. The main benefits of a dedicated radial circuit are that (according to what I was taught at college) when you plug everything in to one radial circuit you effectively “star” earth the hi-fi - this is a known benefit for reducing mains noise and is sometimes used for IT installations. Also, the big drop in circuit impedance should help your system to deliver current more easily which , hopefully, means more dynamic range, etc.

Hope that helps


Exciting times! Mine has been delayed a day so I’ve more time to pettifog over esoterica. I’m going for four I switched sockets. Would anyone have an opinion as to whether this is doable over a single radial or would I need to install two?

As both I and @hoody have said above, you won’t be able to fit any more than one 10mm wire into the terminals, so I don’t see how you could have two double sockets off one radial, unless you use 6mm cable and even 2 x 6mm might be challenging. Why not have a separate radial for each twin socket? This would then give you an option to try using a hydra or MW sparkly block as well as just using the two radials - endless permutations for future tweaking, if that’s your thing! The wire is not that expensive in the grand scheme.

BTW I assume you meant unswitched sockets? I chose MK Logic plus, but I believe Naim used Crabtree in its refurbished and rewired demo room.

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Hi Hoody, welcome to the forum : )

Much has been said in a great many dedicated mains power discussions, that RCDs should been avoided, and it’s not only because of the nuisance trip that can suddenly power-cut the whole audio all of a sudden, but something to do with interference in the electrical path.

So if RCDs pose as a pointless obstacle for audio, and it’s perfectly okay to bypass them using radial circuits on things like burglar alarms or freezers, why should they be necessary for audio?

But over the years i’ve read quite a lot of advice about making sure to avoid those pesky RCDs, and if they are used then the dedicated audio circuit will be unnecessarily compromised. Is this true of false (?)

We should be told :thinking:


Thanks, Clive. Yes that was an autocorrect typo.

I’d say 6mm single radial, terminated with as many sockets as you require (or even more than you think you need, to allow for possible future system expansion? :roll_eyes:), but, ultimately, it’s your choice.

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The electrician who is at this very moment installing my radials x 3, tells me that RCD’s became code in the UK in 17th edition regs (we are currently on 18th edition). He doesn’t know if the RCD affects sound quality, but if I want the work certified, it has to meet regs. So I am afraid if things are compromised, it is necessarily so. :frowning:


The difference with burglar alarms etc is that they are wired as a permanent installation. The issue with using no RCD protection on a dedicated radial was that it could be used for something other than it was intended for. Ie someone could plug a lawnmower into it and presume it was RCD protected. When I had mine done with no RCD, I had to label the socket as ‘non RCD protected and to be used for Hi-Fi only’ to make sure anyone other than myself and the electrician who installed it knew its intended use. As a few have pointed out this is no longer allowed in a domestic installation in the 18th regs.

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I’m going to share this with my sparky friend when he gets back from his hols. We have been musing what may or may not be worth doing. Interestingly he has done work for recording studios that prefer wiring without fuse direct to RCD and explained that their priority is to get rid of the fuses. I may have got that all wrong though, so will check with him when we catch up though. Just thought I’d chuck more grist in the mill…

FWIW he was also sceptical about what difference a radial would make if it shared the same earth as the other circuits.

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However, if the regulation reason was because the UKs Big Chief of Electrical Engineers has decided to put very expensive audio equipment into the same class as electric toasters, hair dryers, rechargers, and all sorts of other home electrical fodder, then it has actually become an unnecessary necessity. :frowning_face:

The real problem is if the dedicated audio main is left in situ after selling the house and moving away. It can’t be certain the next property owner will understand the implications.


Totally agree Debs. One of the reasons to properly label things when work like this is done.


It would still be for be best to remove it all when it comes to selling the house.
There is no accounting as to how the next property dwellers would use it (?)

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I don’t think there is a need for that. The installation should be safe and certified and details of the installation should be included with the certification documentation. Part P took care of most bodged amateur installations, especially when it came to dubious Earthing practices which could be very dangerous.

Since MCB and RCBO ‘breakers’ have the same footprint and are ‘sort of’ interchangeable within a consumer unit, it would not be a big job to remove an MCB and replace with an RCBO if you moved out of a house (a few minutes work for a competent electrician).

This would completely remove the risk that the new homeowner/tenant assumes that a socket is RCD protected when it isn’t.

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But for a new homeowner it wouldn’t be just a question of RCD, it would also be the un-switched sockets with 10mm cabling going to a CU.
This could be simply reconnected so the new homeowner can plug in the flymo.

A dedicated audio main is a rather eccentric and unusual thing to wire in to a house, most normal people out there wouldn’t have a clue of its good or bad potential.

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My electrician installed a 6mm radial circuit using armoured cable and I’ve been very impressed with the outcome. I certainly think the shield and extra large earth has had an impact. Trying a Musicworks block or any of the ring-main sockets and there’s a very noticeable drop in performance compared to the direct radial.