Dedicated Mains installed

Happy to move live wires, but not keen on cutting thick ones live - however not necessary to cut live wires to add a second consumer unit. But DIY in this field requires understanding and competence, and being a bit beyond the permitted small scale work permitted in Britain under building regulations means getting it inspected and approved if you are not a certified person - i had always considered this to be annoying interference and added cost, but Huge's example perhaps shows the justification especially given the risk to life if it is done wrongly. DIY on this topic cannot be advocated, and probably contravenes forum rules.

Re fuse ratings, the relationship to cable size are maximum ratings to provide adequate protection against cable meltdown in event of a fault, and vary according to how the cable is fitted (clipped to wall, in conduit, covered with thermal insulation etc) - but for dedicated hifi use there is no need to have a fuse rating significantly greater than the maximum load, whereas the specification for the cable tends to be considerably greater than the minimum for the load. Appropriately rated fuses would provide greatest protection for the outlet fitments which may well be the weak point when using 10mm cable.

If you want to do it properly, you must cut live wires, unless you get the electricity board round to remove the 100amp fuse in the meter. This is because you cut the meter tails and install a Henley block, from which run two sets of wires, one to each consumer unit. I'm not sure how else you'd add a second consumer unit, unless you piggy back off the existing one, which would be pointless. Also, you want the highest rated breaker possible, for optimum sound quality. The Naim boxes have their internal fuses, as well as fuses in their plugs, so a 50amp breaker is fine. 

Needless to say - please don't go cutting live wires.  Get a locally accredited electrician in to do the work for you.  Also, please note, Naim's mains guidelines are very basic, should only ever be tackled by an accredited electrician, and only applicable within the UK up to the point where they are superseded by changes to the electrical code.  Judging by the pictures, the OP is somewhere within continental Europe so code requirements will be different to the UK.  In other words, Naim's guidelines do not apply - refer only to a locally accredited electrician.

Huge,  the person mentioned I don't suppose they have a Curry's loyalty card if not they have certainly earned one, I suggest they move next to a fire station.

Richard Dane posted:

Needless to say - please don't go cutting live wires.  Get a locally accredited electrician in to do the work for you.  Also, please note, Naim's mains guidelines are very basic, should only ever be tackled by an accredited electrician, and only applicable within the UK up to the point where they are superseded by changes to the electrical code.  Judging by the pictures, the OP is somewhere within continental Europe so code requirements will be different to the UK.  In other words, Naim's guidelines do not apply - refer only to a locally accredited electrician.

At last a no nonsense answer. But getting back to the topic and regarding this so called 10mm2 cable, I know this is the OUTSIDE diameter of it and bearing in mind it carries 3 wires inside, live, neutral and earth plus insulation, there's no way the actual copper diameter of these can't be more than 2,5 mm2 each. It's not the diameter of the whole cable that matters. It's actually the copper diameter of the individual cables that makes all the difference. More than 2.5 mm2 is overkill IMO.

That's the size I've been using on my radial spurs to feed my Naim kit since the 80's. And to be even more specific, I use one for the analogue equipment and a different one for the digital ones. That's how you do it AFAIK.

Period

I don't know why you are getting on your high horse and using the word 'period' to suggest that your opinion is all that counts, especially as you have clearly not read what has been written. 10mm2 refers to the cross sectional area of the cores, and is nothing to do with the diameter of the whole cable. If you are happy with 2.5mm2 wires then good for you, but in my humble opinion, and that of many people on here, 6mm2 is a lot better, and 10mm2 better still. 

Hungryhalibut posted:

If you want to do it properly, you must cut live wires, unless you get the electricity board round to remove the 100amp fuse in the meter. This is because you cut the meter tails and install a Henley block, from which run two sets of wires, one to each consumer unit. I'm not sure how else you'd add a second consumer unit, unless you piggy back off the existing one, which would be pointless. Also, you want the highest rated breaker possible, for optimum sound quality. The Naim boxes have their internal fuses, as well as fuses in their plugs, so a 50amp breaker is fine. 

Point taken re piggybacking. Not convinced that the size of breaker would be significant to SQ, but I don't have experience of it so bow to those who do. IIRC (without checking I can't remember the exemptions) to comply with British wiring regs then an RCD must be included - not sure if that has an effect? 

Of course, how much difference it all makes depends on your home wiring, other electrical usage, and also on the mains supply to your house.

kota posted:

Richard Dane posted:

Needless to say - please don't go cutting live wires.  Get a locally accredited electrician in to do the work for you.  Also, please note, Naim's mains guidelines are very basic, should only ever be tackled by an accredited electrician, and only applicable within the UK up to the point where they are superseded by changes to the electrical code.  Judging by the pictures, the OP is somewhere within continental Europe so code requirements will be different to the UK.  In other words, Naim's guidelines do not apply - refer only to a locally accredited electrician.

At last a no nonsense answer. But getting back to the topic and regarding this so called 10mm2 cable, I know this is the OUTSIDE diameter of it and bearing in mind it carries 3 wires inside, live, neutral and earth plus insulation, there's no way the actual copper diameter of these can't be more than 2,5 mm2 each. It's not the diameter of the whole cable that matters. It's actually the copper diameter of the individual cables that makes all the difference. More than 2.5 mm2 is overkill IMO.

That's the size I've been using on my radial spurs to feed my Naim kit since the 80's. And to be even more specific, I use one for the analogue equipment and a different one for the digital ones. That's how you do it AFAIK.

Period

 

 

Somewhere there is confusion between diameter and cross sectional area (CSA). 2.5mm dia is 4.9mm2 CSA - not sure what is meant in above post? And talk here of 10mm2 cable is CSA, which is about 3.6 mm core diameter ( or a little more due to twisting of the individual wires making up the core bundle as it won't be solid core). And all discussion at British end invariably is copper cable, not aluminium for which larger cables would be needed to be equivalent.

kota posted: regarding this so called 10mm2 cable, I know this is the OUTSIDE diameter of it and bearing in mind it carries 3 wires inside, live, neutral and earth plus insulation, there's no way the actual copper diameter of these can't be more than 2,5 mm2 each. It's not the diameter of the whole cable that matters. It's actually the copper diameter of the individual cables that makes all the difference. 

 

There seems to be some confusion in this thread about cable dimensions. A measurement in square millimetres is a measurement of area, in this case the cross sectional area of each individual core in the cable. Nothing to do with diameter. As HH rightly says,10mm2 cable is not 10mm in diameter, it contains two 10mm2 conductors and an earth. FWIW a typical 10mm2 twin & earth cable has (being oval) an external size of around 17 x 10mm.  

Innocent Bystander posted:

Hungryhalibut posted:

If you want to do it properly, you must cut live wires, unless you get the electricity board round to remove the 100amp fuse in the meter. This is because you cut the meter tails and install a Henley block, from which run two sets of wires, one to each consumer unit. I'm not sure how else you'd add a second consumer unit, unless you piggy back off the existing one, which would be pointless. Also, you want the highest rated breaker possible, for optimum sound quality. The Naim boxes have their internal fuses, as well as fuses in their plugs, so a 50amp breaker is fine. 

Point taken re piggybacking.

Mine was too hasty a response, and reflecting on it it is wrong. Cutting the meter tails and putting into a connecting block with the two distribution boards connected to it is no different from simply disconnecting the meter tails from the main distrib board and connecting to said block, other than that possibly the meter tails might be longer than needed. But ideally what is wanted is to wire up the circuit then get the electricity supply company to connect a new, extra, pair of meter tails to the new distribution board, in parallel with the existing, or if that can't be done then same elec. co. to fit new replacement but thicker meter tails leading to a connecting block, to which the two distrib boards are connected. Requirement for elec. co. Is assuming the meter outlet is sealed as well as its inlet, which commonly is the case otherwise they wouldn't be needed. No cutting of live cables in any of these!

As a matter of interest what are the sort of costs for getting a separate consumer board installed and the wires run? I'm just about to start a fairly major renovation of my house and am wondering if I take the opportunity to get this done at the same time.

chris2000 posted:

As a matter of interest what are the sort of costs for getting a separate consumer board installed and the wires run? I'm just about to start a fairly major renovation of my house and am wondering if I take the opportunity to get this done at the same time.

I leave it to others to suggest figures, but a lot will depend on where the cables are to be run, and complexity of so doing. However doing at same time as doing other work might minimise that. 

I'm glad we all agree now, as I was getting a bit confused. Of course, if the electricity people can come along and take out the fuse from the meter cupboard, everything can be done without live wires. But they will charge for the privilege. A professional electrician will be happy to cut the live tails, equipped with special shoes, a fancy screwdriver and possibly, for added fun, a special hat with a mask. 

As to the cost, it all depends on how long the wires are and how easy it is to run them. The materials cost very little, it's the labour that costs the money. 

Surely the cross section of the wires for optimum sound will depend on the power factor of the load through the wires... Thetefore someone could be quite happy with 2.5mm2 but a different load makeup with some else might require a 6mm2 cross section for the same effective performance. I can't help feeling simply referring to conductor size with no consideration of power factor is too simplistic and might explain why we seem to have endless arguments/discussions on conductor sizes... In short it will as far as I am concerned vary from installation to installation.and reactive load to reactive load. I would have thought a load with many large inductive transformers will have a lower PF compared to less transformers, even though the actual real power could be the same.

Ah yes, of course, I should have realised that.

D'oh!

Simplifying Simon's last post in my own terms, yes, I think the length of the run and anticipated draw would be the greatest determinant of wire gage selection.

I'm still wondering whether the qualified sparkies choose stranded cable or go for solid wire.

What would be the maximum  current draw of say a NAP 250dr based system ?

Ok, back on topic (at least a little ;-) ) You can use different fuses in this fuse holder. I mean it's made out of different materials (Silver, Gold and Rhodium). Has anybody experience with these kind of fuses? It says it does influence the music, bass, surround, brightness etc. I have two types: Silver plated and Gold plated. Silver gives more brightness and Gold more warmth, at least that's my experience.

These fuses satisfy local regulations in an electrical installation in my case! (Just to be absolutely clear)

While I'm happy to use fancy Ethernet cables, I've never even considered the idea of fancy fuses. It just seems like another potential for Audiophilia nervosa, but it might be a great idea. I wonder if the sound effect of silver and gold are real - it sounds a bit odd that silver is brighter (silver is a bright colour) and gold is warmer (gold is a warm colour) - or if it's just a way of making serious profit, as these things are not cheap. I guess if you say you can hear a difference then there is one. How would they work in Powerlines I wonder?

Pcd posted:

What would be the maximum  current draw of say a NAP 250dr based system ?

As no one will use a power amp at max volume,  & depending what other equipment such as sources, preamp & PSU's,  mostly likely less than 1 amp.   However the momentary inrush current at switch-on is significantly higher & can be enough to trip the MCB if everything is powered up at the same time.

Hungryhalibut posted:

While I'm happy to use fancy Ethernet cables, I've never even considered the idea of fancy fuses. It just seems like another potential for Audiophilia nervosa, but it might be a great idea. I wonder if the sound effect of silver and gold are real - it sounds a bit odd that silver is brighter (silver is a bright colour) and gold is warmer (gold is a warm colour) - or if it's just a way of making serious profit, as these things are not cheap. I guess if you say you can hear a difference then there is one. How would they work in Powerlines I wonder?

It is all very subtle, but maybe I want to hear it and all is indeed profit based! There is no scientific explanation at all I'm afraid --> Anyone?. As I have a week off, I am listening to all kinds of music and switch from Fuse time to time. But of course power all equipment down first and remove plug from the wall socket before making the change. I will keep on listening and report my findings.

Remember, of course, that every time to turn it off to change the fuse, the system will take a while to work at its full potential. Perhaps, as the sound effect is subtle, you'd be better just picking one and then forgetting about it. Getting each of your Naim boxes into a separate socket will, I suspect, have far more of an impact. 

Mike-B posted:

Pcd posted:

What would be the maximum  current draw of say a NAP 250dr based system ?

As no one will use a power amp at max volume,  & depending what other equipment such as sources, preamp & PSU's,  mostly likely less than 1 amp.   However the momentary inrush current at switch-on is significantly higher & can be enough to trip the MCB if everything is powered up at the same time.

The act of turning on just the 300PS is enough to threaten the breaker in my dedicated line. But I only have a 45A breaker.

joerand posted:

Simplifying Simon's last post in my own terms, yes, I think the length of the run and anticipated draw would be the greatest determinant of wire gage selection.

I'm still wondering whether the qualified sparkies choose stranded cable or go for solid wire.

With AC it depends on the type of load .. and with efficient transformers its the inductance of the load which will affect the PF. The more reactive the load, the greater the wire gauge needs to be to reduce voltage drop for a given load.  I think some people think of mains load in DC terms i.e. Amps which obviously is not correct.