Mains spur
Posted by: Top Cat on 15 March 2001
Hi folks.
Read with interest all the talk about mains. I have a spare switched fuse on my junction box, and I wondered if it's worth adding (say) a 6mm core spur (a job I feel comfortable doing personally) or if I should be looking to split the incoming mains by means of a block before the household junction box (but after the meter) and 'syphoning' off into a dedicated audio box (a job I'd rather pay an electrician to do).
Would the benefits of the second approach outweigh the additional cost and hassle over the first approach. Any tips?
Also, I've received a copy of the Russ Andrews mains booklet, which goes on about ring circuits being better than spurs - is this true, or RA salestalk - and would it make a huge difference either way?
My plan is to terminate in a pair of 2-way unswitched MK sockets, dedicated for audio.
John
Posted on: 15 March 2001 by Top Cat
quote:
My plan is to terminate in a pair of 2-way unswitched MK sockets
I mean a single unswitched MK double socket, if you get my drift - I'd probably put two on if I was using a ring arrangement, but for a spur one double socket.
John
Posted on: 15 March 2001 by Mark Packer
Why not do what you can do yourself first and see what benefit you reap? Then decide whether to get an electrician in for the serious mains option. (BTW, I did it the second way so that it is separate from the house mains all the way back to the meter -so I don't know what difference if any you'll hear.
I've tried a ring and a spur. The spur sounds better to me.
Also, I found the most significant thing was the taking a separate earth lead fron the MK sockets out to a dedicated mains spike in the garden. This made a BIG difference as far as I could hear. Much better IHMO.
regards,
Mark
Posted on: 15 March 2001 by Matthew T
Has anyone tried on the 'otherside' of the meter, I'm sure there would be some benefits to reap sonically not having the extra hardware in the way.
I think it might be illegal though!
Matthew
Address not supplied 
Posted on: 15 March 2001 by Andrew L. Weekes
Mark,
Does your seperate earth connect with the house earth, or is it totally independant? Was it done by an electrician?
Intuitively I feel a totally seperate earth would be better, but I'm not sure current wiring regulations allow this - I'm trying to investigate this at present. With a PME earthed house, as many newer UK installations are it certainly wouldn't be allowed.
Andy.
Andrew L. Weekes
alweekes@audiophile.com
Posted on: 15 March 2001 by Mark Packer
the hi-fi earth is completely separate from the house earthing. I did it, it works fine
Have e-mailed you directly with (some) further detail.
regards,
Mark
Posted on: 15 March 2001 by Matthew T
Does anyone know where I can get a map of local sub-stations?
and a very thick pair of rubber gloves!
Matthew
Posted on: 15 March 2001 by pcm
I recently tried to "upgrade" my dedicated hi-fi ring main from 2.5mm to 6mm mains cable, but guess what? they don't allow for two "tails" each of 6mm. guage into the terminal blocks within the consumer unit! Nor can I manage 2x 6mm cables the other end in the wall socket terminals!
Solutions?
pcm
Posted on: 15 March 2001 by Andy S
At the risk of repeating myself (from a previous post...)
quote:
For hi-fi a spur is better because with a ring, although you are (effectively) doubling the thickness of the wire to the sockets, you are providing two separate (and different length) paths back to earth. This means that your earth has a "loop" in it - something which Naim try to avoid at all costs. Therefore, it is better to have a single run of cabling that is twice the area than two runs of cabling.
I have a mains setup like Mark (separate Consumer Unit for the hi-fi) which was installed when we rewired the house. Total cost (including 30m of 16mm2 cable!) was probably around £250. Can't say if it was "better" as I also moved my hi-fi to a new room after the rewire.
As to pcms question, I think you can get 10mm2 into each socket if you want. Clearly 2x6mm2 = 12 mm2 (!) so this won't fit. I had to use high current connectors for my 16mm2 and then star out to each of my 4 unswitched double sockets with 10mm2 for the last 30 or so cm.
Andy
Posted on: 15 March 2001 by ken c
mark packer:
can u also email me kenchakahwata@cs.com on your earthing arrangements.
enjoy...
ken
Posted on: 19 March 2001 by Chris Brandon
...AT LAST !!!
...a Hi-Fi sympathetic fully qualified Electrician amongst us !
(Do we refer to you as our very own "Handy Andy" ? ...or just H. ?)
Regards
Chris
Posted on: 19 March 2001 by Henry Cosker
John
Forget ring and go for spur - ring conflicts with single path to earth Naim philosophy. Go instead for 10mm2 cable (available at serious electrical suppliers and intended for double-hob cookers), which will provide both the low resistance and the single path to earth that we all desire! I have taken this path and it is Naim Nirvana. Incidentally JV himself replied to a query of mine regarding ring or spur, and he came down unequivocally in favour of spur. At the time I had two runs of cable to the consumer unit, and he said use just one, don't double up by using both (which is effectively a ring).
Henry
