Dedicated mains - Survey

Silver has 5% lower resistivity, so all else being equal would take more current to heat it to a given temperature, so the current rating would be higher (and cost a lot higher!). Silver’s melting point is also 123C lower than copper, so if subjected to a direct short the wire itself would melt and break the circuit sooner, though that is possibly of little relevance as unless mineral insulated the insulation will melt at a far lower temperature allowing contact between conductors and arcing, which I think is the main fire risk. Rather than silver conductors, a much bigger benefit could be through use of PTFE instead of PVC insulation, with something like 270C vs 60C max temperature.

But if the cable is standard mains rated flex with copper conductors and PVC insulation then indeed 13A would seem insufficient to protect fully from fire risk, should something cause a short circuit. (possibilities include something faulty with the mains socket of the equipment, or with the mains plug into the equipment, or if there is repeated flexing of the cable (unlikely with hifi gear) causing physical breakdown of the insulation, or if the cable lies against a very hot surface such as radiator feed pipe over 60C.) These conditions may seem unlikely, but the possibility exists and that is what the plug fuse is intended to protect against.

If a higher capacity fuse is better for sound quality, then the safe solution would be a higher current capacity flexible lead (cord).

The suggestion that a higher current fuse sounds better is consistent with the notion that a higher current cable from the fusebox sounds better than a lesser cable. However the suggestion that a thinner mains lead is better is inconsistent with this.

Considering all the above, the best thing to do would be audition various mains lead with different thicknesses conductor each with the appropriate size protective plug fuse, to find which works best with the particular mains supply in question. Given that flexible cables can be bought in a wide variety of conductor thickness (in UK commonly 0.5, 0.75, 1.0, 1.5 and 2.5mm^2) all at negligible cost for just a metre or two, and that it is easy and legal to connect into plugs. Making up such mains lead assemblies would be only a low cost to ask an electrician to do, though it is perfectly legal and easy to do as a DIY job for anyone with the basic ability/awareness. Finding appropriate fuse ratings might take a little searching, as may finding fuses: fuses are readily available in at lease 1A, 3A, 5A and 13A, and provided the equipment has its own appropriately rated mains protective fuse, as I believe is normal with Naim products - if not then don’t use a fuse higher than the equipment supplier recommends. In theory it wouldn’t matter if the plug fuse was higher rated than 13A provided appropriate for the flexible lead, and could even if appropriate be higher even than the consumer unit breaker as that would then be providing protection to the flex+fixed wiring circuit, however I say in theory because the question then arises as to the safety of the flex lead mains plug and wall socket combination under higher currents, and this would need to be known before exceeding a 13A fuse in a so-called “13A plug”.

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In the UK it is covered by this:

Where manufacturer’s flex is less than 2m in length, has a csa of 0.75mm2 and is fitted with a non-rewirable plug, it may be rated at 10A and be fused to 13A, in accordance with BS1363 Table 2 note C.” - IET Code of Practice, Page 133.

I have encountered this before, if the flex is less than 2m in length the normal rules can be bent! I believe 3kW kettles apply this rule too, 13A fuse in the plug to handle the load, but short, thin and flexible/manageable cable to the kettle base.

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Roog,

Thanks for clearing this up. The only fly in the ointment here is that a non-rewirable plug is specified (presumably meaning a moulded plug) which of course no Naim power cords have…

Yup, I spotted that too, not sure what the relevance is?

I can’t see why it would make a difference, unless it rules out being able to extend the flex without destroying the original power cord which of course it would with a moulded plug. Clearly there’s a way around it anyway. Thanks again for putting me out of my misery - it’s something that’s always bugged me!

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No problem, I have been asked to exploit this rule before and it went against convention for me too

NOTE: Since you volunteered to ‘move on’ you seem to be continuing your long discussion of this fairly negative, trivial and irrelevant topic.

Well Jim if you had taken the trouble to read the posts properly since I said that then you would see that my posts were in response to Roog who very kindly provided the relevant information. Or do you suggest that I should have ignored him in order to comply with your wishes?

The point under discussion is neither negative, trivial or irrelevant but I had already acknowledged that it was diverting this thread and apologised for it.

Satisfied now?

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You said this thread was not the right place for that discussion, i.e. irrelevant to the thread.

And apologised for it.

Shall we leave it there Jim?

Hi Jim… I’ll confess I just skim sometimes … lol

Hey Pete01, it’s obvious your passion too, for hi-fi.

I enjoy both your posts on the Forum, from your collective experience… thank you both. Doesn’t mean I read everything on the Forum in detail… except when it’s relevant to me.

Ever since getting back here, I’ve reminded myself to stay on thread topic as much as possible - though sometimes, because of the way things are so linked in hi fi, one thing often leads to others… I’m sometimes guilty as charged, Gents. :grimacing: :sweat_smile: :upside_down_face:

So I made a pact with my effusive self, that a digress if any, would be kept really shorter but to stay on topic as respect for everyone else here. The challenge is, many aspects in a system are linked and it’s inevitable we stray some.

Back to dedicated mains that adds value to all … Wish everyone here a good day ahead and to more music! Cheers

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PhilP,
I believe you sire, have been hoisted by your own petard!

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Unwittingly so, I’m afraid… guilty, guilty, guilty… No malice intended anyway.

Absolutely Phil and I wish you well too.

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In 2002 I installed (the sparks did) the clever stuff following details from RKR of forum fame.

The dedicated spurs were finally installed yesterday - it was quite a
job, the tails from the Power company fuse to the meter, meter to a
junction box were increased to 25mm cable. Then a 25mm cable to a 100
fused switch then a 28 metre length of 16mm SWA cable wrapped around the
outside of the house to a Memera 5 way consumer unit in the listening
room, then 5 10mm cables to 4 MK super sockets. One lead has been left
unconnected for “spare and experimental use”

First impressions
More detail, easier to identify voices in vocal work. More snap on bass
sounds.
Snare drums more audible

The electricians were impressed.

The new consumer unit installed in the listening room had a spare switch so it is now feeding the outside power supply for the automatic lawnmower.
Several peope from the forum were quite impressed with the sound.
It is still running.

Here is the diagram of my electrical setup dedicated to the HiFi system.

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…of the lawnmower?

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Perfect. And earth?

I did not mention it. But it goes without saying that it is installed.

Besides, the GigaWatt cable contains 2 grounding wires. The yellow one and a bare one in contact with the shielding of the cable.

At the circuit breaker side the bare cable in contact with the cable shield is grounded.

At the wall socket side, only the yellow cable is connected.

Thus, the entire shielding of the cable is connected to the ground without creating earth loops.

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Thomas,

You forgot the socket for your Cisco switch.

Jim