Radial wiring

ChrisSU posted:

Simon, I seem to remember on another recent thread you were in favour of using a ring rather than a radial. Any particular reason for favouring a radial now? I can see that there are practical considerations, such as half the amount of cable, and less trunking, but just wondered if there were any design issues here? 

Chris, I had an involved discussion with my electrician, and effectively he told me amongst other things because in the UK multiple earth bonding points are no longer required, and in an environment of a non distributed load, there is really no advantage of a ring circuit.. hence my change of view now.

Simon

I've been thinking about Ring vs. Radial and I though the answer was simple; but then I looked at the earth circuit in comparison the the L/N, and the simplicity went up in smoke.  

OK, a ring has an advantage in that 2 of the double sockets are connected directly to the CU, providing a better connection (and being 'peers' co simplifying connection of the equipment).  This also provides for a more direct path to the CU to reduce the influence of one box on another. However the earth circuit is a loop - and earth loops are generally thought bad (although this use may be an exception).  In this case 2 lengths of smaller wire can be employed (e.g. 2x4mm), but they can be run together so not increasing installation cost that much.

A radial circuit has no earth loop, but the impedance from CU to the sockets varies much more as one is closest to the CU and each subsequent one has more wire and an extra contact resistance to overcome.  Furthermore each box plugged in exerts a greater influence on each box plugged in further down the chain.  On the other hand there is no earth loop.  This requires a single run of larger wire (6mm or 10mm)

The only other advantage to a ring is that at a later date it's much easier to convert to two radials, if that is though to be a better arrangement!

I give up!

My cu is 5m from my hifi and easily accessible to change the cable. Years ago, following the advice from a dealer, I had it at 6mm2 for a short while. I then changed it to 10mm2 Pirelli cable and the difference was instantly obvious. After hearing the improvements, I changed many other connections, polished components, etc.. Every link in the mains chain makes a difference.

Considering the short 5m distance, length on this occasion, doesn't matter. 

FT, good advice and food for thought on wire gauge and mains sockets.. 

Graham, I think the clicks and buzzes you describe on the mains are more to do with regulation and impedance rather than RFI.... I am afraid true RFI couples across air albeit attenuated and does not limit itself to copper...

As I said when I had my house converted from PME to TT I had to have a new Master CU which also had the new master earthing point.. Remember in TT there is no earth link to neutral at the premise or by the distributor.. When my master CU was replaced and PME removed my mains quality significantly improved.. the master live and master neutral then went directly from my meter to the new master CU.. There is physically no option for seperate feeds to another CU from the meter now,  and there may be regulatory earthing considerations in daisy chaining multiple master CU's in a TT setup... I am not sure I want to go there given I had all that removed only a few years ago.. and things improved ..

i guess it would be interesting to hear from anyone else who has a TT setup, I am assuming most here on PME?

Simon

Finkfan posted:

He Happy, what sonic improvements were there with 10mm over 6mm? 

When my hifi is moved it will only be 2.5m from the board. If 10mm is so much better then I'll have that fitted

10mm is so much better. I cant remember in detail exactly the improvements as it was years ago now but I distinctly remember being pleasently surprised. I recall thinking the bass had not only gone much deeper but it was also far better controlled. The top end also seemed more full rather than sharp, more detailed. To be honest the whole sound was as if I had upgraded the system components to the next level. Sixteen years and many box upgrades later im still using 10mm multiple radials fed by 32a mcb's in a dedicated consumer unit. Upgrading the mains really is that good.

Mr Happy, given the points that FT made what do you terminate your 10mm2 radial into?

Simon-in-Suffolk posted:

Mr Happy, given the points that FT made what do you terminate your 10mm2 radial into?

 MK logic range unswitched sockets with 32mm deep pattresses. They fit easily as long as you position the cables first, rather than trying to ram everything in randomly.

Thanks Mr Happy

will use 10mm in my new set up. Should be quite the eye opener after only using the house ring main. 

Mr Happy ... thanks

In olden days the hi-fi sat in splendid isolation and connected to nothing but the mains. We could star earth and put it on a separate spur and that was that. Now we connect the hi-fi to the Internet. Are others leaving their NAS drives, servers and switches on the household ring main? Is there any benefit in putting this stuff on a second spur and are their any issues with earthing? The later may be a particular issue without hi-fi grade Ethernet cables (like my Audioquest).

Keith

KRM posted:

In olden days the hi-fi sat in splendid isolation and connected to nothing but the mains.

Cruel.

Chris

Interesting questions KRM. Is there an earth connection in Ethernet cables? I thought it was just twisted pairs?  If not, then does it matter if the servers etc are on the normal house ring main? 

KRM posted:

 Are others leaving their NAS drives, servers and switches on the household ring main? Is there any benefit in putting this stuff on a second spur and are their any issues with earthing? The later may be a particular issue without hi-fi grade Ethernet cables (like my Audioquest).

Keith

Good idea if it can be done.      But (big BUT)  if you have all Cat7 like your AQ,  or any STP,  & your switch carries the screen thru' its ports (look for metal shrouds),  its a good idea to make sure it does not carry the screen between the dedicated hifi earth (the Naim port is earthed) & the ring main earth (the NAS might be earthed)  there will be a small potential between them.    Plus its not a good idea to have more than one LAN earth (ground) anyway

...  better SQ & no screen ground to worry about.    

Mike I use STP cables; are you saying I have a big butt?  

Very interesting post, and informed replies.....in the coming weeks we should complete the purchase of a house back in our Yorkshire homeland...

We plan to undertake some refurbishment, so an ideal opportunity to install some dedicated wiring for the main Naim system which will be moving there.

From the post, the following outline spec looks like it should allow for a meaningful first discussion with the Electrician:

Radial circuit

dedicated consumer unit - 32amp mcb's - own (split) meter tail

10mm2 cable

double unswitched MK logic socket

Appreciate any feedback/further suggestions to consider...

Is it more effective to run more than one cable from the CU to a socket  e.g. run 3 seperate cables to 3 seperate sockets (giving 6 powerpoints)...or run further sockets from the 1st socket (using smaller diameter cable) ?

Also, will install some ethernet cables...cat6 UTP looks to be favoured....

Many thanks, and am very interested in how Simon's work progresses and sounds!

Have a good weekend

I shall be installing a dedicated supply for my system. I shall also be using 10mm cable. I'm inclined to spur further sockets from the first thereby keeping the same single earth path for all components. 

Makes sense - let us know how it goes/sounds...

have a good weekend

Unfortunately it doesn't make sense:  You get a single earth path, but you also get the possibility of different earth potentials along that path.

Thanks Huge

so the seperate cables to seperate sockets would be the preferred/more effective option ?

Have a good weekend

Unfortunately I think the British low voltage wiring regulations (part 'P') won't permit the circuit I think would be best, so here's a permitted alternative that I think would be better.

Wire it with 2 cables within the same conduit, and then wire up to 4 dual sockets (all physically close together) as a small dedicated ring main.  You may like to consider the configuration as A-B-B-A (with no association to Swedish music):  Where sockets 'A' are connected to the CU and a 'B' socket; and 'B' sockets are connected to an 'A' socket and a 'B' socket.  This contrasts to A-B-C-D for a radial circuit.

I'm not describing the other circuit as I believe that would contravene the Forum AUP.

Huge posted:

Unfortunately it doesn't make sense:  You get a single earth path, but you also get the possibility of different earth potentials along that path.

if the additional sockets are directly either side, wired back to the first? 

Finkfan posted:

Huge posted:

Unfortunately it doesn't make sense:  You get a single earth path, but you also get the possibility of different earth potentials along that path.

if the additional sockets are directly either side, wired back to the first? 

You'd need to contact a Part 'P' qualified electrician to determine the legality of that arrangement.

But superficially I think it's OK (I had to look it up though) as I believe it constitutes a single spur from a radial circuit.  I don't believe it would be permitted to do four sockets in quite that way.  For three it's probably about the best arangement, but extending it could be problematic as the point of connection of any further sockets becomes critical for compliance.

The best arrangement ive found was listed earlier in this post, using multiple 10mm radials.

You can have multiple sockets wired on a single radial circuit if you wish to go down that route. It doesn't contravene the iee electrical regs, although I found that it sounded inferior to multiple radials.

And just 1 double socket on the end of each? 

Finkfan posted:

And just 1 double socket on the end of each? 

Ive used single sockets, so one piece of kit on one circuit. A bit extreme perhaps but the improvement was well worth it.