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Kevin Stephens's picture
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New Mains supply
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This isn't about kettle leads hence the new thread instead of getting mixed up in the other discussion.

(FWIW I don't have any faith in "audiophile" kettle leads, but have found that good quality interconnects have a dramatic impact on sound quality, which I believe to be due to their effect on electrical propertiesof the source/pre-amp circuits which they become part of)

I want to put in a new radial main from a dedicated circuit breaker in my consumer unit to a new dedicated multi socket in the lounge for my HiFi.  The main reason for doing this would be to position a multi wall socket behind the HiFi instead of the current arrangement of long flex across the carpet to a cheap multi block.  This is easy to do as I can access the underfloor void to lay the cable, and just need to get an electrician in to mount the circuit breaker and test the circuit; and then only to preserve the Part P certification on my house.

Spin off benefits may be a reduction in interference from all the stuff that currently shares the same ring main with my HiFi.

Would there be any significant benefit of runing some sort of screened cable (eg SWA) instead of a normal flat twin and earth?  if so what would be the best solution? 

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RE: New Mains supply

 

This is worthwhile reading as you are embarking on such a project.  

I think you'd have to have an exceptionally severe problem, like taxi cab transmitters next door, to need screened mains.

http://www.russandrews.com/viewindex.asp?lookup=1&region=UK&currency=GBP&article_id=pgringmain_instructions&customer_id=PAA0436040113241MBDUGXWJKIFYZSYF

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RE: New Mains supply

I am not a house wiring sparky, but the diagram you have linked to does not seem to comply with part P of the building regs, or the IEE 17th edition wiring guidelines. In particular, the HiFi outlet does not appear to have RCD protection.

I would welcome the opinion of someone more qualified than I.

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RE: New Mains supply

andyjm wrote:

I am not a house wiring sparky, but the diagram you have linked to does not seem to comply with part P of the building regs, or the IEE 17th edition wiring guidelines. In particular, the HiFi outlet does not appear to have RCD protection.

I would welcome the opinion of someone more qualified than I.

You do not have to use an rcd to comply with 17th edtion of the regs I will have a look so as to give you the exact wording but I think you have to chase the cable in at least 50mm or put it in a metle conduit which is earthed/ bonded  if you use a 4mm or 6mm twin and earth and your cable run isn't to long your earth loop impeadance will be lo and give you o.4 second diconnection time if your supply is a TT system ie over head cables you will need an rcd as you will be relying on an earth stake which in most cases is not as good as aTNC or TNCS . one uses the lead sheath of the incoming cable to provide earthing and the other uses a permant earth nuetral PME  if I remember rightley one should give an earth loop impeadance of 0.8 ohms and the other 0.35 ohms the TT  can be anything over 200ohms hence the need for an rcd . I will be installing a 6mm twin and earth 32 amp supply  which will run 3x double sockets behind my hifi I will run it back to my trip board if the results are good I will leave it at that if not I will split the incomming tails and install a seperate trip board  for hifi the tails are the cables comming from your meter into your trip board I would recomend that you get in a sparky  if you want to go thie roote as if you do not know what you are doing It can be very dangerous when I have checked the regs I will post back with anything which I have missed or isn't correct

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Kevin Stephens's picture
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RE: New Mains supply

Thanks, I understand most of that. However I'm at a loss as to why an RCD should reduce SQ, or indeed why Russ Andrews hasn't cornered the Market in "audiophile" quality RCDs.

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RE: New Mains supply

Kevin Stephens wrote:

This isn't about kettle leads hence the new thread instead of getting mixed up in the other discussion.

(FWIW I don't have any faith in "audiophile" kettle leads, but have found that good quality interconnects have a dramatic impact on sound quality, which I believe to be due to their effect on electrical propertiesof the source/pre-amp circuits which they become part of)

I want to put in a new radial main from a dedicated circuit breaker in my consumer unit to a new dedicated multi socket in the lounge for my HiFi.  The main reason for doing this would be to position a multi wall socket behind the HiFi instead of the current arrangement of long flex across the carpet to a cheap multi block.  This is easy to do as I can access the underfloor void to lay the cable, and just need to get an electrician in to mount the circuit breaker and test the circuit; and then only to preserve the Part P certification on my house.

Spin off benefits may be a reduction in interference from all the stuff that currently shares the same ring main with my HiFi.

Would there be any significant benefit of runing some sort of screened cable (eg SWA) instead of a normal flat twin and earth?  if so what would be the best solution? 

Running SWA will screen the cable from common mode interference - a signal (stray RF) being induced into both live an neutral conductors.  It will make no difference to noise already present on one of the conductors.

While it wont hurt to run a separate spur, if your fridge arcs every time the compressor starts, then the noise will be coupled back along the fridge ring to the busbar in the consumer unit and will travel down your spur. The noise doesn't just stop at the consumer unit.

Just had another look at that wiring diagram from RA.  What is a directional A/C cable?

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RE: New Mains supply

Kevin Stephens wrote:
Thanks, I understand most of that. However I'm at a loss as to why an RCD should reduce SQ, or indeed why Russ Andrews hasn't cornered the Market in "audiophile" quality RCDs.

Because there is no such thing as an audiophile RCD, Consumer Unit or anything else related to mains wiring.

Bill

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RE: New Mains supply

A standard filter block is all you need, however if you really want to get the mains as good as can be, use an active  stabilised power unit with battery backup as this will also correct the usual voltage fluctuations that occur during the day.

Get a qualified electrician in if any modification is required to the mains. (And make sure he is certified)

Hope this helps

Bill

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RE: New Mains supply

I went even further in my previous house and put a separate consumer unit in just for the hi-fi - possible as the house was being completely re-wired. You should have seen the look on the electricians face when I said what I wanted!

Main problem was that I couldn't tell how much (if any) of a difference it made as I didn't have a 'before' to compare it to.  I just used standard cabling and can't say it was ever a problem, although every house will differ in its susceptability to interference and you only do this sort of thing once, so maybe worth it if the cost differential isn't too bad (the marginal cost for me was minimal as I was renovating the whole house)

I personally wouldn't take too much notice of Russ Andrews advocating his 'audiophile' circuit breakers. IMO he argues that everything makes a difference, which for me undermines his credibility as some of the stuff he sells is good (sounds like you and I agree on the relative importance of cables by the way).

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RE: New Mains supply RE: New Mains supply

abacus wrote:

Kevin Stephens wrote:
Thanks, I understand most of that. However I'm at a loss as to why an RCD should reduce SQ, or indeed why Russ Andrews hasn't cornered the Market in "audiophile" quality RCDs.

Because there is no such thing as an audiophile RCD, Consumer Unit or anything else related to mains wiring.

Bill

I was attemptng to be ironic :?

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