Separate spur limitations

You need a radial circuit, not a spur.

The 1 inch cable you refer to is your in coming mains, this is a 25mm T&E armoured, your spark won’t be touching this

from the meter is the 16 or 25mm meter tails which feed directly into your CU

get the spark to fit a Henley block and connect the tails to this, now you can add a separate CU, one dedicated for the HIFI run individual spurs from this in 10mm T&E and remember to allow for future expansion, the cost of more sockets while your doing this work is peanuts 

your looking at spending a few hundred pounds not £5000 unless you’re having solid gold sockets

so youre looking at a new CU a Henley block some meter tails 10mm T&E and sockets, the main bit here is cable and sockets 

A fully qualified spark ( ie an AP ) earns around £180 on site so if you slipped him a bit more than that for an easy days work

your main concern and cost is the location of the sockets in relation to the CU 

if you can do the cable runs that will save you a lot, that bit is the time consuming donkey work, just leave him to do the second fix and terminations and testing 

lyndon

Excellent advice, thanks a lot Lyndon!

Yes good advice from Lyndon.

I would ask for a ring circuit rather than a radial as I have tried both and prefer the sound of the former.

Ray

There was a very good thread here earlier this year which is well worth reading

Dedicated Mains

This finally got me to pull my finger out, get a few quotes and  put in a dedicated mains feed. It's probably been the best value upgrade i've done in its effect on my system.

Lyndon offers excellent advice above 

James

Huge is right.. however it depends where you are and what you want to achieve. In the UK the regulations permit a spur being upto 13 amp connected load from the ring main via a direct connection. A radial allows a direct connection back to the consumer board supporting multiple sockets  and higher combined load... typically on this forum when one refers to dedicated mains in the UK for their audio one is refering to a dedicated radial.

I however do have a dedicated spur, with my spur cable using a RF/HF impeding weave... but it is fused at 13 amps where it connects to my ring main... it works for me... 

And referring to the dimensions given in the OP, when talking about cables the conductors are sized and referenced by their cross sectional area (mm²) not diameter, as it is that that more directly relates to current carrying capacity. Each 10mm² cable has a conductor diameter  of about 4mm (it will have several cores so slightly over the diameter of a single solid core), so maybe about 6mm with  insulation. Current carrying capacity of 10mm² cable is about 52 amps (standard twin & earth in trunking), while 6mm² is about 38A. I doubt it would make any difference to sound which size of cable for a dedicated hifi circuit, though some people claim it does - but as the cost difference is not big in the context of the whole installation people generally simply go for thr bigger, though I think judicious choice of socket is required for the thicker cable to fit without difficulty, as it is a lot larger than normally run to standard 13A sockets.

One potential problem with a dedicated radial feed for hifi could be any subsequent room changes - either a decision for any reason to use a different room, or simply a major layout change in the room, especially if it is a large room, so to avoid hassle and cost down the line, you need to have surety as to where the gear will sit.

When I rewired my house, instead of a radial circuit I installed a dedicated ring to the lounge (being the only room large enough for music room), with sockets all around the room. This was based on the desire to separate that room where, if hifi was on nothing else would be likely to be, from other power circuits in the house, while allowing for any future changes in the room. And I am glad I did that rather than picking a single outlet position, as although I had carefully planned the layout of the room, when the time came to move into the room it turned out not to ‘work’ in the planned layout, and the room ended up arranged completely differently, with the the new hifi electronics location where it would have required an 8m or more extension cable from the original planned position  And it is comceivanpble that one day I will move it to a different position a further 4m away. With a ring in the room no location is more than 2m from a socket on the dedicated circuit.

Innocent Bystander posted:

And referring to the dimensions given in the OP, when talking about cables the conductors are sized and referenced by their cross sectional area (mm²) not diameter, as it is that that more directly relates to current carrying capacity. Each 10mm² cable has a conductor diameter  of about 4mm (it will have several cores so slightly over the diameter of a single solid core), so maybe about 6mm with  insulation. Current carrying capacity of 10mm² cable is about 52 amps (standard twin & earth in trunking), while 6mm² is about 38A. I doubt it would make any difference to sound which size of cable for a dedicated hifi circuit, though some people claim it does - but as the cost difference is not big in the context of the whole installation people generally simply go for thr bigger, though I think judicious choice of socket is required for the thicker cable to fit without difficulty, as it is a lot larger than normally run to standard 13A sockets.

I have used both 6mm and 10mm t+e cable on dedicated radial circuits fed from a dedicated consumer unit for the hifi only. The 10mm radials sounded significantly better than the 6mm ones. There isn’t a lot you can do about the main incoming service cable but you can contact your supply company and request a main fuse upgrade to 100A if it isn’t already, as this gives the sound a lift too.

There are  3 formats you could use when adding sockets;

A spur...which adds additional sockets to an existing ring mains. Not recommended for hi-fi as its merely an extension of an exisisting ring and carries all the noise and interference generated by household equipment and comprises multiple pieces of joined cable. 

A Radial, which adds a single cable direct from the CU to a set of sockets wired in series

A ring, which adds 2 cable runs, one from the CU to the sockets and the other from the sockets back to the CU

Over the years I have tried both radial and ring format and various types of cable. 

Conventional wisdom calls for the use of 10mm2  T&E but personally I hate the stuff.  I’ve always had far greater success using something like Acrolink Stressfree 7N P4030II, which gives a far more natural, musical rendition. 

For sockets I’ve had great success with the Furutech duplex unstitched gold sockets.  

Photos of my ten year old installation might help. It looks like the incoming feed is split after the meter in the black box and bottom centre. Separate tails feed a dedicated 40 amp consumer unit for the hi-fi spur - located under the domestic c/u on the other side of the wall.

Clear sonic benefits from day one and well worth doing; but be aware that a dedicated spur will not eliminate periodic transformer hum; well not here anyway.

John.

I like your Smart Meter sticker - think I'm going to have to knock up something similar as we're now going through the constant ""your meter needs replacing with a Smart Meter" - "No it doesn't"" call process with our 'leccky supplier.

Apologies for potentially hijacking this thread but I am about to go down the route of installing a separate spur and I want to make sure I am crystal clear on what I need. I contacted Naim support for guidance but apparently they are no longer allowed to provide guidance as they are "not registered electricians" hence me reaching out here. 

I believe I need to ask my electrician for the following : 

• Installation of a dedicated radial Spur, which includes:
• A separate Consumer Unit with 50amp breakers 
• Meter tails to be split with a Henley Block
• A single run of 10mm squared cable to unswitched MK double sockets 

Have I got that right? Have I missed anything ? 

I then have two supplementary questions : 

• There is wood paneling in my new listening room and therefore I would like to minimize the number of sockets I install as they will need to go into the paneling. Would an MK double socket with a Russ Andrews Mains Extension Block work just as well ? 
• I have both an Intel NUC ( for Roon) and a NAS in my system. Is it ok to put them on this spur or should they be separate 

Thanks in advance for feedback and input provided 

That sounds right, yes. Make sure that the earth from the new consumer unit goes directly to the meter, not via the existing one. You should use Type C breakers as they won’t trip every time you switch on the stereo. Keep the NAS on the household supply but use a UPS to protect it. 

Terrysmi posted:

I believe I need to ask my electrician for the following : 

• Installation of a dedicated radial Spur, which includes:
• A separate Consumer Unit with 50amp breakers 
• Meter tails to be split with a Henley Block
• A single run of 10mm squared cable to unswitched MK double sockets 

Have I got that right? Have I missed anything ? 

In addition to HH's comments, the only thing I'd say is to have an isolator switch instead of an RCD in the consumer unit. The regs still allow you to do this (this will be changing next year) but the cable run must be surface mounted and the sockets must be labelled as not RCD protected). I had mine done earlier this year -

In the meter cupboard, A Henley block splits the 25mm2 meter tails between the house consumer unit and the new Hi-Fi consumer unit. The incoming 16mm2 Earth cable is split here too. 

The meter sits on the other side of the wall from the consumer units in the garage. The new tails run through the wall and up the conduit into the new consumer unit. 

From the new consumer unit, a single 10mm2 T&E cable runs along the wall before heading up to the loft via a bedroom wardrobe. As the new radial is not RCD protected, the cable must be surface run to meet the regs which works fine for the installation cable route we decided on. 

A single 32A Type C MCB and Isolator switch.

As the lounge is on the opposite side of the house to the garage we needed an unbroken run of 25m T&E from the new consumer unit to the lounge. The cable runs up to and along the loft, exits the gable end wall and then makes the final drop down the wall inside conduit to the back of the new socket.

James, here is a picture of mine. It looks like I have an isolator switch rather than an RCD. My MCB is higher rated than yours: I’ve no idea why. We use 100mm2 SWA cable that runs round the outside of the house under the flowerbed. There are no labels anywhere - I imagine it was done before labelling was added to the regs. 

Thanks Nigel – I was just making the point that most electricians will automatically fit an RCD unless you ask specifically. As with all electrical work, regulations change over the years and as yours was done some time back different regs would have applied so it's fine without labelling.

James

hungryhalibut posted:

My MCB is higher rated than yours: I’ve no idea why. We use 100mm2 SWA cable that runs round the outside of the house under the flowerbed.

If you need a cable that big, no wonder you need a higher rated MCB!

Ah yes, 100mm2 would be rather large!! I meant, of course, 10mm2. 

Why doesn’t anyone consider a mini power station in the garden? Say solar powered?  I trust that would be expensive, but so is Naim.

Thoughts?

To extend my last post awaiting approval:

£20k for a personal power station.

Off grid solutions solve some problems (no heavy industry sharing your mains supply for example) but introduce others such as noise from the inverter(s). I think i'd rely on the National Grid and a dedicated radial sourced as close as possible to the incoming house feed.

Keep it simple 

Self sufficient power is fine... but on a serious note... solar panel inverters are notorious generators of RFI and high frequency harmonics on the mains and in the EM field around the panels/house... it has improved over the years... but if you have solar panels you probably want careful consideration for your Hi-Fi mains. A solar panel inverter is like a massive switch mode power supply. I can detect RFI interference from a panel roof implementation 150 metres away from my house... and that is airborne interference...

Hi,

I have four single spurs (radial) direct from my Hi-Fi dedicated CU. One of which I use for my LP12 and another for my Naim kit (Supercap/Superline, NAC and NAP all from the same unswitched 13 amp socket) whilst the other two spurs are spare and unused as they are not terminated in the listening room (but could be).

My question is would I be better off in:

1. Converting these into two ring circuits (one for the LP12 and the other for my Naim kit);
2. Connecting  the two unused  spurs such that each bit of kit (LP12, Supercap, NAC and NAP) has it’s own dedicated spur; 
3. Leave it as is?

If I were to change I would use a qualified electrician.

Regards,

Richard

Simon-in-Suffolk posted:

[...] if you have solar panels you probably want careful consideration for your Hi-Fi mains.

[@mention:1566878603876589]

As I have solar panels and the associated inverters at home, can you share some of your thoughts on this? Thanks!