Noise and DC on mains and new radial

I know much has been written on this subject and I don't intend to repeat it. I've cut and pasted all the excellent, if oft-conflicted, info' I've collected from the very useful and informative, previous threads and decided to instal a radial & include a balanced power supply from Airlink - yes Mike is a really helpful chap, as reported. But, I'm enjoying my music so much, just now, I hesitated over whether to bother. Then I tried switching off all the breakers on my CSU save for the hifi room sockets, to see if I could hear any difference in sound reproduction. I deliberately used a Christine McVie track that pushes the envelope on highs - even on the new Dynaudios. I compared listening with breakers on and off three times and each time her highs were clearly less harsh with the other breakers off - by which I mean the circuits were broken. I've not read of anyone trying this before. It Just seemed to me to be an easy, fast way to see how much the rest of the electrics might be affecting the music. Can this be considered a relevant, useful test? Or is my ignorance of electrics painfully obvious?

Original Post

Adding a dedicated mains circuit with its own separate consumer unit will give a degree of isolation from other appliances in your house, but you'll still have a house full of appliances running. The test you've done, if I've understood correctly, has turned all of these appliances off completely, which is going further than just putting them on a separate circuit, so maybe has a greater benefit. Despite this, I would recommend going for a dedicated mains supply. Having recently installed one with its own separate consumer unit, I would agree with others on the forum who have found it very worthwhile. No experience of the Airlink thing, though.

Thanks Chris. That puts my little experiment into excellent context in a way which hadn't occurred to me. Shame it's more than a radial will achieve. A second but dedicated mains feed on a second meter, perhaps?! But it was interesting to see the effect those other elements are having on the sound quality. The Airline, as I understand it, eradicates DC from the hifi radial which, in so doing, has been shown, here, to reduce/eradicate transformer hum and reduce sonic harshness. Whether it does so in all instances is moot. I'll definitely go ahead, though. Sparks coming next week to measure the incoming power so we can select correct BPU. 

eagle3333 posted:

Thanks HH; yes, this is the route I'm pursuing. My sparks not very happy about trying to fit 10mm2 cable into a socket, though. And disagreements here about whether it's sonically more beneficial than 6mm2. Old arguments never conclusively settled.. 

If you only need one (double) socket, getting a 10mm cable to fit is perfectly possible. Your electrician might think you're nuts, but he'll be able to do it. 

I think you may struggle with 10mm2 if you want more than one double socket. I found that with 6mm2 you could just about take the feed to others - I have 4 double sockets. I guess you could over come this if you say wired 3 radial circuits with 10mm2 to three twin sockets. I'm not sure if this would mess with the star earthing arrangement you can achieve? It seems very important with Naim systems and may be more important than 10mm2 or 6mm2 cable choices? Having tested my system on the house circuit and the dedicated circuit I can tell you the difference is greater than black boxes.

Thanks All. Voltage measurement next Wednesday and will be interesting to see what's actually coming in. Meantime, I'm going to stick with just one double socket. Family friend sparks sucked in much air when I mentioned 10mm2. Thinking. A dedicated earth sounds like a good idea in order to keep the Hifi radial away from the main CSU but I'll let the sparks advise on its feasability/safety. But Even then, isn't the Hifi radial still subject to upstream influences from the main CSU, before the meter?

Thanks FT. I'm going to put in a balanced power supply which is meant to sort out DC. Was going to put it in the radial but Airlink recommended to put it in straight after the meter so it controls the feed to main CSU as well. Which kind of ties in to your comment.

That is where my BPS is too. Hope the installation goes well. I also opted for an Airlink BPS and 10mm2 radial supply. Some of the Airlink products have several output taps, which allow you to control the output voltage in 10-12V steps. This was helpful for us, as we could drop the output from 242V to 230V, which apparently helps "take a little stress off the Naim power supply components" without adversely affecting sound quality. I started a thread about this about 2 years ago.

Best regards, FT

Putting an isolation transformer between the meter and the main CU for the house is a bad idea - it'd then have to be rated at 125A (125% of fuse rating and main fuse is normally 100A).  It also then won't provide isolation from the effects of other electrical items in the house.

Better to use a separate CU (connected to the meter tails by Henley blocks)) for the HiFi circuit and use the isolation transformer in balanced mode (i.e. wired CTE) on that.

KRM posted:

I also used a consumer unit which has a 100a isolator switch instead of an RCD (supplied by Russ a Andrews). This is fine as long as the socket is labelled for hi-fi use only. Finally, I have an earth spike.

 

Unless you have a TT earthing arrangement (either originally installed or having converted to this when your earth spike was installed), it can be potentially very dangerous to fit an additional earth spike; particularly as many (most?) houses in the UK use the PME (TN-C-S) earthing system and using an extra earth electrode with this can result in fires if there's a fault.

You should also note that you NEED an RCD in ALL circuits with TT earthing, so one of your two arrangements doesn't seem quite right.


Please get this confirmed / checked by an intendant qualified electrician whose Part P certification is up to date.

Hi KRM considering using 2x6mm as you have ...... however, at first thought - I would not have thought it possible to get 2 x 6mm into a 13a socket cable input point ........... when yours was done what make unswitched socket did you use.....did all go smoothly.....

Hi Huge,

The consumer unit comes with certification that it is ok when used with the labelled socket.

I know what you mean about earth spikes and I thought they weren't allowed, but I was reassured by the electrician that it's perfectly fine the way he's done it (I know him and he's good). Naim advise still recommends mains spikes, by the way (or the Naim advice passed to me by the dealer does).

Keith

Richieroo posted:

Hi KRM considering using 2x6mm as you have ...... however, at first thought - I would not have thought it possible to get 2 x 6mm into a 13a socket cable input point ........... when yours was done what make unswitched socket did you use.....did all go smoothly.....

Hi Richieroo,

The electrician said it would be easier to wire two x 6mm into the unstitched MK double socket than 1 x 10mm.

Keith

KRM posted:

I also used a consumer unit which has a 100a isolator switch instead of an RCD (supplied by Russ a Andrews). This is fine as long as the socket is labelled for hi-fi use only. Finally, I have an earth spike.

I'm surprised to see RA selling this consumer unit, which is made of plastic, and will not conform to current UK electrical regs in the majority of installations. That doesn't make it illegal to sell it, but getting it signed off under the current IET regs is another matter.

ChrisSU posted:
KRM posted:

I also used a consumer unit which has a 100a isolator switch instead of an RCD (supplied by Russ a Andrews). This is fine as long as the socket is labelled for hi-fi use only. Finally, I have an earth spike.

I'm surprised to see RA selling this consumer unit, which is made of plastic, and will not conform to current UK electrical regs in the majority of installations. That doesn't make it illegal to sell it, but getting it signed off under the current IET regs is another matter.

Hi Chris,

No need to be surprised. The "the plastic, self-extinguishing enclosure conforms to UL94".

Keith

KRM posted:

I also used a consumer unit which has a 100a isolator switch instead of an RCD (supplied by Russ a Andrews). This is fine as long as the socket is labelled for hi-fi use only. Finally, I have an earth spike.

 

Please, please check your earth electrode has been validated by an electrician. Installing an earth electrode on a PME based earthing system...(  this is where your utility  distribution has a shared primary low impedance path to earth, which is common in the U.K. ) ... could  result in potentially lethal situations but almost certainly cause considerable damage to your connected appliances  if there are certain faults conditions in your utility supply. Think damage similar to some types of none direct lightning strikes, but you almost certainly won't be covered by insurance.

Now if your 'spike' is relatively high impedance to earth (like bonding a cold water pipe) and not a proper earthing electrode, then the chances of issues will be significantly reduced but it will almost certainly be ineffective at doing anything relevant.

if you want local true earthing, you need a TT system, and if you haven't one you need to pay an electrician to convert your utility supply. I have done this, and my earth electrode is a formal impedance validated electrode installation with my primary house supply earthed to it... and yes definitely worth doing properly and my noise levels dropped hugely. Audio was only my secondary motivation for doing this but hugely benefitted.

Simon (all).  I would ban the sale of earth spikes in UK except to Part P qualified electricians.  Too many people are playing with stuff they have not a clue about.   I have a good example of this only a few weeks ago when I got into conversation with someone who was planning to dig up an area of his garden to install an earth plate (& would I help with the wiring).  He read that the larger sq/ft area plate did so much more than a spike & would turn his TV into something amazing.   First it took me quite a while to make him believe his property does not have a ground spike & the words of wisdom were from a USA www & completely non-applicable to UK & to his house that has PME (TN-C-S).    

The spike was fitted by an electrician.

The advice to fit a spike came from Naim (via the dealer), not from Russ Andrews, although I did ask him if it would be ok and he said it would be "fine" as long as it was fitted by a qualified electrician.

The advice from Naim was:

"Use a dedicated earth for the sockets. Use the house earth to protect the cable run, but don’t connect it at the sockets. Get the sockets’ earth from a totally separate rod outside the house. The rod should be as close as possible to the sockets, but needs to be somewhere where the ground doesn’t dry out too much."

Keith

 

Indeed, Mike, though I never endorse banning, as earth electrodes are legitimate... of course there are different sorts and it's not all about electricity utility regulations... in RF engineering both amateur and professional they can be essential and nothing to do utility supply, but for those most take exams (professional and amateur) where these matters are addressed.

I also think there is a lot of myth and mumbo jumbo discussed on the web about earth electrodes, utility earthing and the remove RF. Simply earthing a lead doesn't remove RF, RF voltages don't work that way. To sink a RF wavelength voltage the source to point of highest impedance of the electride be an odd value quarter wavelength in length...  if the length is at an even value quarter wavelength it will have no effect in sinking the RF what so ever... that is why for RF sinks you can use a star setup with different length radials with an electrode at the end of each radial which is what I use for my non safety earth utility electrode.... but I could safely facilitate until I converted my domestic supply to TT.  I optimise my RF sinking up to 30 MHz (approx 10 metres) and I feel it it is up to these frequencies/wavelengths that are most likely to affect audio content ccomponents.

But yes a single earth electrode will have minimal RF impact if any. The mesh idea you see in the states for amateur tinkering seems to work on the assumption the ground is super conductive, and the mesh is between your earth feed and couples to your assumed  highly conductive soul thereby modelling a large with respect to the relevant wavelengths highly conductive ground plane.... I am not aware of our soil in the UK being super conductive, and even then as you say you should only tinker once your utility supply is converted to TT.

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