Optimal House Wiring

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JohnS
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Optimal House Wiring

Post by JohnS » 2008-05-02 10:56

Hi,
I’ve got the real luxury of building a new room in my house, and it’s going to be where my hifi sits! It’s not quite a music room, but almost… the point of view depends who you talk to ;-)

It’s going to be about 60m2 so probably 6x10m. I’ll be running a Klimax DS, Kontrol, Solo’s and potentially powered speakers such as 350's.

What should I do about electrical wiring specification? Since it’s new, I can luckily specify whatever’s best. Any advice?

So far from what I've read I think I need to put in dedicated circuit(s) from the fuse board and use fuses rather than circuit breakers if allowed (the house is in France).

After that there are several options and I don’t know which is best.

Should I put in several mains circuits (spurs), one for each component?
Should I put in a ring circuit and then wall sockets for each component?
Should I have just one circuit and then us a good extension board?
Should I have one ring circuit for source, one for power amps and one for speakers?
Should the 350’s be plugged in with the other components or have their own circuits? One circuit for the two or one each?
Some other combination of the above?
Is there anything special I should ask for in terms of earthing?

How thick should the cabling be? Thicker the better I guess? I can see a range of mains wire the UK standard being 2.5mm2 or 4mm2 but I can find cables for sale up to up to 16mm2 that can carry 110Amps, seems rather thick to me! I imagine that is excessive, I’m not even sure that can be fitted into a wall socket…

It’s quite a few months away yet, but I’m interested and trying to understand in advance what’s best so any advice would be appreciated.
Thanks
John

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Post by Charlie1 » 2008-05-02 13:11

Hi JohnS,

I can't comment on much of this, but have found an extension block much more preferable to connecting my system to a pair of twin wall sockets that happened to be located behind the system. Note that the order in which you connect devices to the block is just as important.

I plan to install a dedicated spur myself, but may move house this summer, so it's on hold for now.

You could always try out some different mains cables yourself. You could just run a dedicated spur from mains board through the house to where your system is at the moment. Obviously you need to be careful and this is just a quick test as you don't want pets chewing the cable or anything. If you don't know how to do this (I certainly don't) then you'll need a sympathic electrician as I'm sure it's against regulations, but as long as it's just for testing and you're careful, then I don't see a problem. It's what I plan to do myself when the time comes.

I found this link interesting although it's mainly aimed at Naim users: -http://www.acoustica.org.uk/
They suggested that a dedicated earthing rod makes as much difference as dedicated spur. Just something else to consider.

Good luck with the project and please let us know how you get on. Rgds,

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Post by lejonklou » 2008-05-02 22:09

Hi John!

I have played with these parameters a bit, but have never been able to A-B dem all the options to the extent that I've understood it completely. I can therefore share some guidlines, but no exact advise:

One dedicated circuit from fuse board and an extension board (distribution block) near the system - YES
Ring - NO
Large fuses (or none) whereever possible - YES
Cabling thickness - difficult! Mixed results with this. The make and type of cable seems to be more important than thickness. Excessive thickness seems to do no good. Check directionality of this cable by listening before final installation.

One question regarding the system: What are you going to use the Solos for if you have powered speakers such as the 350's?

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Post by ThomasOK » 2008-05-03 16:01

I have found the same as Fredrik in that a dedicated circuit to a good power distribution unit gives the best performance. I can't comment on ring connection as we don't have that in the US. The fuse question also doesn't work here for the most part as most houses now use circuit breakers instead of fuses and the plugs and outlets are not fused in the US either.

I have also found that cable thickness is no guide to quality. I replaced the heavier cables that came with my active ATC speakers with thinner Linn power cables and the sound was noticeably improved. And even at extreme volumes - which I have sometimes been known to use :) - there is no compression of the sound due to the thinner power cables.

The best bet to find the optimum power cable to go from the box to the wall socket is to get some short lengths of samples with a high enough current rating and make up some extension cords using the same connectors. Start out making two cables using the same wire in different directions to check for the best sounding direction. Do that with each different wire and then compare the different wires running the proper direction. In order not to have to buy a bunch of AC plugs and sockets you can do the directionality test with one wire at a time and then compare two wires at a time keeping the better as the reference. This way you can get by with two or three sets of plugs and sockets. Make sure the cables you make up are the same length and try to also tighten the screws to the same tightness - you want to eliminate as many variables as possible.

I am also curious as the where the Klimax Solos fit in.

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Post by JohnS » 2008-05-07 13:41

Hi,

I have the Solo's already, and I'm looking around at speakers. For the 350's, I'm considering 350 Passive, they still require power for the active bass.

john

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Post by lejonklou » 2008-05-08 03:08

Of course, passive 350's! Didn't think of that.

Please keep us posted on how things develop.

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Post by ThomasOK » 2008-05-08 16:24

Got ya. When I see "powered speakers" I generally think of active speakers. I wasn't considering 350 passives as powered although the do indeed have powered servo woofers, hence the need for an AC hookup.

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Post by Charlie1 » 2009-08-13 13:36

Hi JohnS,

How did you get on in the end? I'm looking at having an electrician install a dedicated spur for the hi-fi. What UK mains wiring did you opt for in the end and did you ever compare any?

Anyone else compared different cabling in the UK or have any suggestions generally?

Many Thanks,

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Post by JohnS » 2009-08-14 11:26

Hi Charlie,

I'd love to have a conclusion, but building projects take a long long time here.

I'm meeting the electrician soon to talk through the plans and building should start in September, so I should have some results towards the end of the year. It's going to be very hard to compare wiring other than theoretically in advance as I can't get the equipment in the room until it's built (!) and then I think the electrics go in before the flooring and plastering. Listening comparisons are just are not practical.

I'm only going to do this only once, so what I was planning to do was to go a bit over the top, unless the electrician says it's illegal/totally stupid/too expensive:

A dedicated spur (big fat cable) from the main house supply entry point which goes to its own fuse box behind the wall with the hifi (current fuse box is full anyway) and then three seperate fused spur circuits from there. One for the source components, and one each for the L/R power amps and speakers. As noted above by Thomas, I may need to get the wire lengths the same for the three short spurs.

A new earth point just for the hifi which goes across all of the hifi sockets. There are foundations being built, so why not have a new 'quiet' one rather than the existing house earth!

At the moment I'm not sure if it's better to have multiple sockets on the wall, one for each bit of kit, or to rely on three of Fredriks extension boards.

Has anyone got any views on the above.

The house also has an existing 3-phase supply which I don't use at all, is this if any practical use here?

I'll let you know what the electrician says (probably that I'm mad), but also it's to french standards rather than in the UK.

Regards
John

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Post by Charlie1 » 2009-08-17 08:01

Thanks John for your response - much appreciated. Sounds like you're going all the way with this and yes please let me know what the electrician comes back with.

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Post by JohnS » 2009-08-25 19:37

I saw the electrician today

So this is what he recommends, and luckily it's not too expensive :

Put in a new earth that serves the hifi sockets only.

A dedicated spur from the main house supply that goes to a dedicated fuse box just behind the wall with the hifi. It has three fused circuits for the hifi only:

1*20A fused spur for the left speaker 350p and solo (solo's maybe later)
1*20A fused spur for the source components
1*20A fused spur for the right speakers 350p and solos (solo's maybe later)

This is where it gets interesting - to use the 3-phase power supply in the house. Each of the 3 spurs above uses a common neutral, but each fused spur uses a different phase from the 3 phase and thus gets it's own 240v. He considers this the most stable arrangement across the three circuits.

I had never thought of using the three phases in this way.

Does this make sense? Any views on if it may be better, or at least no worse than monophase?

Any idea how low the earth resistance should be? Legal minimum is 100 ohms, but more earth points can get to a lower figures, but how low is good?

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Post by Ducky » 2009-08-25 20:57

Some of the guys on our Dutch Hifi forum made quite a study of this. If you can get under 2 ohm, you are doing OK I think :D

Lennart

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Post by lejonklou » 2009-08-25 21:32

Hi John! Just a few comments:
JohnS wrote:Put in a new earth that serves the hifi sockets only.
Probably a good idea. I assume it will go together with the neutral at the same point as the other earths do.
A dedicated spur from the main house supply that goes to a dedicated fuse box just behind the wall with the hifi.
Sounds good.
It has three fused circuits for the hifi only:
Perhaps good, but probably better to run the entire system through the same fuse (assuming it's large enough to handle it all). This can be a trial and error thing.
Each of the 3 spurs above uses a common neutral, but each fused spur uses a different phase from the 3 phase and thus gets it's own 240v. He considers this the most stable arrangement across the three circuits.
I don't think this is a good arrangement. I've had customers made such installations and when they've later tried connecting the entire system to just one of the three phases (+fuse), the HiFi has sounded a lot better.

My impression is that three different phases will carry three slightly different sounding voltages. To have them all going into the same HiFi creates a confusing result. One advantage, however, is that with all three phases installed, you can compare them and pick the one which sounds the best.

Thanks for the earth ohm figure, Lennart!

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Post by JohnS » 2009-08-26 09:10

Hi, thanks for the comments, it is really helpful.
JohnS wrote:Put in a new earth that serves the hifi sockets only.
Probably a good idea. I assume it will go together with the neutral at the same point as the other earths do.
The new Earth is at a different part of the house from the existing earth, does it need to be connected to the existing earth? I had presumed two wires (live/neutral in monophase) from the exiting supply and then a local earth not connected to the existing one. Basically to keep it 'quiet'. I didn't realise the earth needed to be connected to the neutral. Can this be done in two places?

A dedicated spur from the main house supply that goes to a dedicated fuse box just behind the wall with the hifi.
Sounds good.
Phew!
It has three fused circuits for the hifi only:
Perhaps good, but probably better to run the entire system through the same fuse (assuming it's large enough to handle it all). This can be a trial and error thing.
This is where I get confused, the max for a circuit is 20A here. A solo is about 900w max (not average in use I know, but the idea is to give it maximum headroom? or at least to allow them all to startup at once, maybe they peak at 900w at startup?), but if you have four (fingers crossed), then you are already at 3600w max which is around 16A. Add the 350p's and maybe some day a lottery win and another pair of solos and then I'm over the 20A. being at the limit doesn't sound like a good start.

Previous posts said it's better off a single socket and a single power block, but with a larger system it is too much for a single power block, a single socket or even a single fused circuit. That is why I was planning three circuits and three fuses, future proofing.... But this sounds worse?


Each of the 3 spurs above uses a common neutral, but each fused spur uses a different phase from the 3 phase and thus gets it's own 240v. He considers this the most stable arrangement across the three circuits.
I don't think this is a good arrangement. I've had customers made such installations and when they've later tried connecting the entire system to just one of the three phases (+fuse), the HiFi has sounded a lot better.

My impression is that three different phases will carry three slightly different sounding voltages. To have them all going into the same HiFi creates a confusing result. One advantage, however, is that with all three phases installed, you can compare them and pick the one which sounds the best.
That is really interesting! I'll go back to Monophase.

I won't be able to test which is the best phase as the electrics will go in before the plastering, floors etc. so the room is not usable until finished. Then again, maybe the electrician can change the phase at the beginning of the original spur... need to ask about that one!
Thanks for the earth ohm figure, Lennart!
Yes thankyou Lennart, that is low! Apparently it really depends in the local soil. Time will tell how many points we'll need to sink.

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Post by anthony » 2009-08-26 09:28

Fredrik, correct me if I am wrong, but I recall from a long time ago, where someone had 3 phases available, they managed somehow to get one appliance across 2 phases and it saw 415V.....
Is this, if correct, another reason not to have 3 phases.

John I think the chances of drawing more than 20 amps is unlikely, never had a problem in a similar setup.

Naim power supplies are very vunerable to drawing high currents on switch on but Linn seems ok

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Re: mains supply

Post by JohnS » 2009-08-26 10:18

Hi Anthony
Thanks for the reply. If I've got it right, with 3-phase you have four wires; the three phases and the neutral. Between the neutral and any one of the phases you get 240v, but the voltage between the phases is 380v. But you'd only get this if your electrician decides to wire it up that way. you have 3*240v if done correctly.

So you'd go for one 20A circuit, two or three wall sockets, two or three power blocks (because it's hard in a practical sense to plug all the equipment into one...) and not worry about it even if you have a fully active solo setup? Now I'm dreaming by the way!

I'm starting to think, 3*20A circuits, 3 sockets, 3 mains blocks...??

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Post by anthony » 2009-08-26 11:43

Hi John

Yes somehow there 2 of the phases were connected, a highly unlikely scenario....but it happened.

I do not have experience of wall sockets vs extension blocks so cant comment. I use a bank of MK unswitched, all I know as a reference it sounded much better than the ring main.
I know of someone running an aktiv system from his 30 amp cooker socket. I suppose if you use 2 x 20 amp fuses you could still plug into 1 of them and use the other as a reserve.
I am sure Fredrik will add a useful comment.

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Post by lejonklou » 2009-08-26 18:20

JohnS wrote:The new Earth is at a different part of the house from the existing earth, does it need to be connected to the existing earth?
That's a question for your electrician, because he knows the rules. It all depends on the wiring layout and he will probably know the best way to get a "clean" ground.
This is where I get confused, the max for a circuit is 20A here.
That's plenty, no problem running your dream system from that. Just avoid switching all the Solo's on at the exact same time. :)
That is why I was planning three circuits and three fuses, future proofing.... But this sounds worse?
Most likely, yes. Please note that the differences are not small when you go from one to several phases (circuits). It does sound very different. And my experience so far is that it's been a lot worse.

Most of the time I have also found that more than one fuse is worse. But in a few cases it's been better - and then it's always been the poweramps that have been put on a separate fuse.

My vote goes to one phase, two or three fuses and several sockets for each fuse. Then you can compare how many fuses the system should be using. If you do, please report your findings!

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Post by JohnS » 2009-08-26 19:29

Thank you Fredrik, as ever, remarkably useful advice from yourself and the whole forum.

As a conclusion from various postings, I'll do:
  • Monophase
    Dedicated fuse box
    New earth (2ohm target)
    Three 20A fused circuits (not circuit breakers)
    Each fused circuit with three wall sockets (3 groups of 3, left/centre /right of room)
    1 cable from the fuse box to each set of three sockets (2.5mm2 or 4mm2 section)
    Cable length identical from fuse box to sockets in the wall for each set of sockets.
This way I can play with:
  • All from one socket/fuse with a big mains block.
    Power/source from 2 wall sockets on one fuse with 2 mains blocks
    Power left/Source/Power right from three wall sockets on one fuse with 3 mains blocks
    Power left/source/power right on three seperate fused circuits using 3 mains blocks
    Power/source/power on three seperate fused circuits directly plugged into the wall.
There are probably a few more options, but it's easily enough to get started with. Hopefully it'll be ready to go in early 2010...
Regards
John

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Post by Charlie1 » 2009-09-01 21:09

Here's a related topic on the Naim forum:
http://forums.naim-audio.com/eve/forums ... 3362941427

Reading the thread, it sounds like a ring is better than spur, but wouldn't a spur make a round trip anyway? Perhaps it just means that the return leg goes via another route. I'm uneducated in electrics so please forgive any misunderstanding.

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Post by anthony » 2009-09-01 21:25

A spur comes to a dead end whereas a ring does return. Don't trust Naim purchasers because they are all pallindromes.

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Post by anthony » 2009-09-01 21:29

Think they are recommending a spur, so all is forgiven...humble apologies

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Post by lejonklou » 2009-09-01 21:41

I have no practical experience with ring circuits in mains installations (it's not practiced here), so I can't rule it out to 100%.

BUT nearly all other experiences I have with HiFi electronics suggest that a mains ring should be worse. When something similar is done in power supplies, distribution blocks or power cords, the result is a "bigger" sound that is less musical.

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Post by lejonklou » 2009-09-01 21:50

Another reason I wouldn't use a ring is that they most likely produce stronger magnetic fields inside the room. Not exactly desirable.

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Post by Charlie1 » 2009-09-01 21:51

It was the following post that caught my eye ref rings and spurs...
It is the LENGTH of the spur to the common join point at the consumer unit which is important. If you can get this to under 3 metres then you are lucky and it will probably sound better. But if, like me, you have several metres (7+) of spur, then the danger of RF pick-up increases dramatically and you are far better off with a smaller RF cross-section. You can get a harsh un-tuneful sound.
I've tried several rings and spurs and found it all sounded best of a single ring, although the spur was quite good too.
racecar is a pallindrome, although it doesn't at first appear like one <- that's from my 'How to Make Interesting Friends' handbook.

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