dedicated mains advice needed

hi all,

getting the room decorated so finally chance for getting a dedicated mains installed (will require cable running via garage then up into upstairs floor boards before dropping down internal wall), have read quite a few posts but had a few queries so clear what am asking the electrician to quote for 

found some 10mm2 cable,

PRYSMIAN 6242Y TWIN & EARTH CABLE 10MM² X 25M GREY

 

 

know will need to ask for a henley block for the new consumer unit to connect 

 

questions i have are:

is the standard 10mm2 the best to use for sq, as seen all sorts available including some sellers selling shielded more expensive cables for mains?

know naim manual quotes 35-45amps for the supply, will the above consumer which has a 50amp circuit breaker be best for sq? if not what consumer units have you guys used?

re: connecting of the new hifi consumer unit to the existing via tails, what exactly am i asking the electrician to do?  

as ever council appreciated as feels like a bit of a minefield this one  

thanks 

mat

 

Original Post

Hi Matthew

I listened to different sized cables for my dedicated supply. 2.5mm radial and ring. 6mm radial and ring. And 10mm radial. 10mm won for me. Gave the best balanced sound and the deepest bass. Might sound strange, but true. I've not messed about with shielded cable so can't comment on that. I went with a wylex consumer unit. The MK will be just as good and I'd be surprised if there is any difference in sound. A 50A mcb is ok for 10mm cable but installation method can effect this. Your electrician will advise. When it comes to connection you want to ask your electrician to split the tails. These will go into Henley blocks. Tails from the meter into the blacks and tails out to your existing house consumer unit and another set to your new MK Hifi consumer unit. Also get an MK unswitched double socket for your hifi. The 10mm will fit in no problem. 

I used Prysmian 10mm T&E, can't comment on how it compares to others, but it works for me.

I recently had the consumer unit you mention installed, but I bought the version with just a 100amp isolator switch, and added my own choice of MCBs. On Naim's recommendation, these were 32 amp Type C, as opposed to the more widely used type B that your sparky would probably choose. Note that these are MCBs, not RCDs, so you will need to check that your electrician is happy to instal them.

The Henley block splits the single pair of tails coming from your meter into two tails, one for the existing meter, and another for the new one. I didn't need this, as I already had an isolator switch fitted which serves the same purpose. Either way, your electrician should be able to deal with this.

Ask your electrician if he will run the earth cable from the new CU directly to the earth terminal that you should be able to see near your meter, as opposed to running it via the main consumer unit.

You will need to sort out how many sockets you need, as fitting more than one double socket with 10mm cable, while not impossible, is quite challenging!

As always, you should make sure your installation complies with local (in my case, UK) regulations.  

ChrisSU posted:

I used Prysmian 10mm T&E, can't comment on how it compares to others, but it works for me.

I recently had the consumer unit you mention installed, but I bought the version with just a 100amp isolator switch, and added my own choice of MCBs. On Naim's recommendation, these were 32 amp Type C, as opposed to the more widely used type B that your sparky would probably choose. Note that these are MCBs, not RCDs, so you will need to check that your electrician is happy to instal them.

The Henley block splits the single pair of tails coming from your meter into two tails, one for the existing meter, and another for the new one. I didn't need this, as I already had an isolator switch fitted which serves the same purpose. Either way, your electrician should be able to deal with this.

Ask your electrician if he will run the earth cable from the new CU directly to the earth terminal that you should be able to see near your meter, as opposed to running it via the main consumer unit.

You will need to sort out how many sockets you need, as fitting more than one double socket with 10mm cable, while not impossible, is quite challenging!

As always, you should make sure your installation complies with local (in my case, UK) regulations.  

Hi just been looking was this the consumer unit you refer to 

MK SENTRY 4-MODULE 2-WAY PART-POPULATED MAIN SWITCH CONSUMER UNIT (6885G) has 100amp switch 

And the MCB 

MK SENTRY 32A TYPE C MCB (40707), the 32amp version 

will get electrician to confirm am wanting to show him parts before hand so clear what I need doing 

intended getting single socket fitted (switchless mk  logic plus or maybe the furutech gold one) then running a power strip from that for ease, currently use wire world matrix 2 maybe upgrade to the Nordost version at some point if can demo 

 

thanks again

 

mat 

 

 

I wanted to avoid the need for a power strip (if I needed one, I'd probably go for a Grahams Hydra.) I used two MK double unswitched sockets, and just to prove that it was possible, managed to fit two 10mm cables into a terminal  . My electrician came up with an alternative, which was to use a Henley block to split the T&E cable (in the same way as it's used for the meter tails) which made fitting more than one socket a lot easier.

I have a fair bit of experience in wiring up the type of installation you're talking about, Here are some of my learnings from those experiences.

Some heavy duty cables used to run from fuse box to socket never sound right. They sound like they need to burn in but they never do.

Even the best cables will initially sound bad and will need time to burn in, so how do you know if your cable is 'hi-fi suitable' or not?  You don't, at least not without ca. 100 hours burn-in, so you need to use 'audiophile approved' cable i.e cable that other audiophiles have reported as suitable for hi-fi use. This will almost certainly cost you more as a.  its better cable and b. its usually obtained through specialist stores serving audiophiles so pricing is premium. Is it worth it? Depends how you feel about getting the whole job done, then waiting for it to sound better while all hope slowly dies after spending 200 hours listening and waiting for your system to begin sounding good.   My advice; buy cable known to produce really good sonic results. You'll be happy you did long after you've forgotten what you paid.

Next sockets.  At least in the context of my various systems, they always sounded better when they were fed from a single, suitably rated socket. This automatically implies the use of either a mains block, a hydra-like device or a dedicated mains conditioner. A poor quality mains block will completely destroy SQ, so again you need to go the 'audiophile approved' route. Typically such blocks offer much better contacts for improved plug grip and equal resistance between all earth points. The latter is critical as all you need is one component sitting on a high resistive earth to ruin your system's sound.

 When all is done properly, what can you expect?

No more mains-borne switching transients. All aspects of the sound will improve, some of which are just 'more' like more bass, more treble extension and sparkle, wider deeper sound stage and some which actually fundamentally increase listener involvement, like more pace and rhythm, so higher boogie factor, less harshness and grunge  and greater 'musicality' and clarity.

Proper mains supply is one of the most important upgrades you can do, but it must be done properly to realize all the sonic benefits.

 

Just for the sake of clarity, and to prevent members doing harm to either themselves or their property, I assume that this installation is a UK one, yes?

I am very wary of this sort of thread, mainly because advice is far from universally sound - different countries have very different electrical infrastructure and electrical code.  What may be fine in one may be both illegal and even lethal in another.

Naim's advice is fairly general, and definitely only for UK installations.  In every case, regardless of where you live, you must ensure your installation is either carried out by or approved by a fully qualified electrician who is completely up to date with the relevant electrical code for where you live.

Richard Dane posted:

Just for the sake of clarity, and to prevent members doing harm to either themselves or their property, I assume that this installation is a UK one, yes?

I am very wary of this sort of thread, mainly because advice is far from universally sound - different countries have very different electrical infrastructure and electrical code.  What may be fine in one may be both illegal and even lethal in another.

Naim's advice is fairly general, and definitely only for UK installations.  In every case, regardless of where you live, you must ensure your installation is either carried out by or approved by a fully qualified electrician who is completely up to date with the relevant electrical code for where you live.

Yes Richard is for a UK installation and will be done via qualified electrician 

 

 

Richard Dane posted:

Just for the sake of clarity, and to prevent members doing harm to either themselves or their property, I assume that this installation is a UK one, yes?

I am very wary of this sort of thread, mainly because advice is far from universally sound - different countries have very different electrical infrastructure and electrical code.  What may be fine in one may be both illegal and even lethal in another.

Naim's advice is fairly general, and definitely only for UK installations.  In every case, regardless of where you live, you must ensure your installation is either carried out by or approved by a fully qualified electrician who is completely up to date with the relevant electrical code for where you live.

Hi Richard, what is Naims advice when it comes to a dedicated electrical?

Elkman, it's fairly general and definitely UK only. Off the top of my head it's a 30A radial from a dedicated CU with 6-10 mil mains cable and unswitched MK sockets. Best check with Steve Hopkins to be sure though. Of course, current electrical code for your area trumps all other recommendations.

Matthew Johns posted:

thanks all been really helpful getting understanding up, reading up i noticed quite a few people use shielded cables like Lapp CY cable, does this really make any difference (or is it the case of price bump up for so called audiophile grade as usual)

CY cable is intended for commercial use in areas where electromagnetic interference may be a problem. Weather it benefits you as a hifi mains cable will depend on weather you have EMI causing a problem in your house. 

For those interested in main supplies for Hifi, take a look at the Signals Hifi website, their latest blog. They have just opened new premises with new wiring etc, and were disappointed with the sound from their Naim Statement amps. The Statement amps did not like their twin radial supply.

Bryce Curdy posted:

What are the pros and cons of a dedicated consumer unit vs a dedicated RCD (or MCB)?  And if only opting for a dedicated RCD rather than consumer unit is all of this splitting the tails and Henley blocks chat irrelevant?

The usual advice is to isolate the dedicated circuit from the rest of your house's electrics as much as possible, and a separate consumer unit helps a lot woth this. I ran a half-baked dedicated supply from a spare slot in my main consumer unit as a temporary measure, and couldn't really hear a difference. Doing a proper job with a separate CU made a big difference. 

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