Dedicated Spur advice please

I don’t think there is a fact sheet but if you do a search in these forums you will find this topic has been covered many times listing what others are using in great detail.

I use multiple 10mm twin and earth cables with earth connections star wired, one circuit for each piece of kit. These are fed from a dedicated mem consumer unit. I found the upgrade from the household ring circuit very worthwhile. I also tried 2.5mm and then 6mm radial circuits but found 10mm to be significantly better.

Separate consumer unit, splitting the meter tails with a Henley block. 10 mm2 wire to unswitched socket. Take earth from HiFi consumer unit direct to the meter, not via the existing consumer unit. 50A Type C MCB. 

Thanks guys...I’ve been reading the threads...lots of strong opinions out there. I hope the electrician doesn’t blow a fuse when I ask for 10mm cable and Henley blocks etc. Taking the earth directly to the meter sounds controversial...or maybe it’s something he will not blink at.

Hopefully I will get a discernible improvement in SQ with the configuration I end up with. If I end up with standard uk 3 pin sockets will I have been wasting my time.? I was thinking of buying a hydra thingy to connect my olive 52 and 250.

I’ve recently bought a nova and want new speakers/cable but will post separately.

He shouldn't blow a fuse. If he's a decent electrician, he will understand what you want and be able to interpret the regulations to ensure a safe, compliant installation. Nothing suggested above is controversial. On mine the earth is split just after the incoming feed - one goes to the existing consumer unit, the other to the Hi-Fi consumer unit. The Henley block (to the right of the meter) just splits the L & N meter tails between the two consumer units.

This is what I mean by taking the earth back to the meter box. It was all done by a properly certified electrician. When it was first done, the HiFi earth piggy backed off the domestic box, using a skinny little wire. Having it redone properly did seem to improve things, and we have a very silent background on the system, with no transformer hum.

Docv posted:

 I hope the electrician doesn’t blow a fuse when I ask for 10mm cable and Henley blocks etc. Taking the earth directly to the meter sounds controversial...or maybe it’s something he will not blink at.

 

There's nothing controversial about taking the earth to the meter - or more correctly, to the incoming wiring the other side of the meter, as you can see in James and HH's photos. This is where the earth from your main consumer unit will normally be going. An electrician looking for a quick easy way to instal the earth may run it to the main consumer unit instead, from where it will share the earth cable back to the incoming connection.

Splitting the meter tails with a Henley block is also a standard thing for an electrician to deal with. They would more often do this if you needed an extra consumer unit for a shower, to wire in a garage, or if your main one has just run out of space. The problem you may have with some domestic sparkies is that their training will tell them that domestic circuits will need nothing more than 2.5mm cable, that they need to be RCD protected rather than only using MCBs, etc. They will also know that 10mm cable is more awkward to handle, and fitting it into a standard socket is a tight squeeze, so it makes their job a bit more tricky. Best find an electrician who doesn't look at you like you're a complete nutcase if you want the job doing properly. 

ChrisSU posted:

There's nothing controversial about taking the earth to the meter - or more correctly, to the incoming wiring the other side of the meter, as you can see in James and HH's photos. This is where the earth from your main consumer unit will normally be going.

Both photos show the earth connections going to the correct point,  the HH installation especially as it has a notice (label) indicating its a Protected Multiple Earthed System (PME).  This earthing system is typical of more modern domestic installations where the house wiring earths & earth bonded connection to all metallic gas & water pipes are taken back & connected to the incoming main Neutral.

Docv posted:

Thanks guys...I’ve been reading the threads...lots of strong opinions out there. I hope the electrician doesn’t blow a fuse when I ask for 10mm cable and Henley blocks etc. Taking the earth directly to the meter sounds controversial...or maybe it’s something he will not blink at.

Hopefully I will get a discernible improvement in SQ with the configuration I end up with. If I end up with standard uk 3 pin sockets will I have been wasting my time.? I was thinking of buying a hydra thingy to connect my olive 52 and 250.

I’ve recently bought a nova and want new speakers/cable but will post separately.

If you are going to all the effort of installing a dedicated mains then I certainly wouldn’t use a hydra as this will normally degrade the sound. If using sockets then the ones most use are the mk logic range unswitched.

I’m not sure about that - a hydra is a really good way of connecting multiple items, but is no use if you might want to use powerlines. It’s probably best to have two or three double sockets installed at the same time, which will be cheaper than getting the electrician back later. 

Grateful thanks for advice and photos...I am wondering if a hifi sympathetic spark might be the best option...my single spur project has been added to other jobs which the chap I’ve lined up has agreed to do.

I’m in north Shropshire...any suggestions/ contacts? I will do my own research tomorrow via naim dealers in Shrewsbury and Chester.

cheers

hungryhalibut posted:

I’m not sure about that - a hydra is a really good way of connecting multiple items, but is no use if you might want to use powerlines. It’s probably best to have two or three double sockets installed at the same time, which will be cheaper than getting the electrician back later. 

My father tried a grahams 3 head hydra on his system having read so many good reviews but was disappointed as it made the sound noticably flatter and more two dimensional.

He asked me to come over and give my opinion. Indeed it had taken a downturn so we reinstalled the 3 seperate naim stock leads into their 3 unswitched sockets. The sound immediately improved by a significant margin.

Does this mean a separate 10 mm spur for each socket or can they all come off the one spur...excuse my ignorance 

I found either will give the sound an improvement. I tried and found one 10mm for each piece of kit sounded better than one shared circuit. A bit like the hydra I mentioned above. 

The problems arise when trying to make a 10mm ring circuit with several sockets

The sockets then have to hold two 10mm wires in each terminal...virtually impossible to do ... better to go with 6mm ...it's still very substantial

My solution is to have a system that only needs two mains leads, which fit into a twin unswitched Crabtree socket perfectly. That’s a 15 year old Crabtree, when they made top notch stuff and Naim supplied their equipment with Crabtree plugs. 

Probably a silly question but I'll ask it anyway; does the installation include running cables nice & tidy inside the same runs as the originals, or do you end up with some plastic channelling stuck on the wall in the style of the job done by the baboon who rewired my grandad's house some years ago and left it looking like the worst cowboy sparky on the planet had had an off day? Presumably you can pay peanuts and get a low-rent job or add a load onto the cost to make it look as if nothing changed. Tempted tbh, if it didn't end up looking like a cheap job...

The installation is whatever you want it to be.  

Docv posted:

Does this mean a separate 10 mm spur for each socket or can they all come off the one spur...excuse my ignorance 

I once tried to fit two bits of 10mm cable in the back of an MK socket, and it was a struggle, but I did manage it. Then there's the back box - even the largest will only just contain the cables when you push the socket onto it. I discussed the feasibility of this with my electrician, and he suggested splitting the cable with a Henley block under the floorboards, and running two cables from there to the two double sockets I wanted. This turned out to be a more practical alternative. The other option would be to run a separate length of cable all the way from the consumer unit to each socket. Alternatively, keep it simple and just put in a single socket, then run a Hydra, PowerIgel, or whatever, from there. 

ChrisR_EPL posted:

Probably a silly question but I'll ask it anyway; does the installation include running cables nice & tidy inside the same runs as the originals, or do you end up with some plastic channelling stuck on the wall in the style of the job done by the baboon who rewired my grandad's house some years ago and left it looking like the worst cowboy sparky on the planet had had an off day? Presumably you can pay peanuts and get a low-rent job or add a load onto the cost to make it look as if nothing changed. Tempted tbh, if it didn't end up looking like a cheap job...

Chris - This is where you need a good electrician. I wanted mine done as a single run of 10mm2 T&E and be non RCD protected. To be compliant to the regulations the cable had to run surface mounted and also get from one side of the house to the other. I worked out an initial route and ran it through with the electrician to determine the final installation run. The roof space was no problem as the cable is clipped to the main centre joist. To get to the new CU in the garage, the cable drops down through the ceiling within a bedroom cupboard and through the floor into the garage. A small run of surface mounted white conduit runs through here. To get from the roof space to the lounge it exits a gable wall and runs down the outside wall inside black conduit and back through the wall behind the new socket. All done neatly and unobtrusively.

Just for completeness for the OP, this is what I gave my electrician to explain what I wanted.

Small point, but relevant to the electrician doing the work...

What you want is a radial circuit (and not a spur).

ChrisR_EPL posted:

Probably a silly question but I'll ask it anyway; does the installation include running cables nice & tidy inside the same runs as the originals, or do you end up with some plastic channelling stuck on the wall in the style of the job done by the baboon who rewired my grandad's house some years ago and left it looking like the worst cowboy sparky on the planet had had an off day? Presumably you can pay peanuts and get a low-rent job or add a load onto the cost to make it look as if nothing changed. Tempted tbh, if it didn't end up looking like a cheap job...

This will depend on how good your electrician is in terms of routing the cable, and making good afterwards. It can be disruptive, and may require a plasterer, especially if there are any wall  chases required. How hard this is will depend on the route the cable has to take, but I don't believe it's ever really a problem to do it discretely. Sometimes it just takes a bit more time, and therefore costs a bit more money, to do it well.

Docv posted:

someone please send a fact sheet or link

 

http://www.acoustica.org.uk/t/mains.html

james n posted:

ChrisR_EPL posted:

Probably a silly question but I'll ask it anyway; does the installation include running cables nice & tidy inside the same runs as the originals, or do you end up with some plastic channelling stuck on the wall in the style of the job done by the baboon who rewired my grandad's house some years ago and left it looking like the worst cowboy sparky on the planet had had an off day? Presumably you can pay peanuts and get a low-rent job or add a load onto the cost to make it look as if nothing changed. Tempted tbh, if it didn't end up looking like a cheap job...

Chris - This is where you need a good electrician. I wanted mine done as a single run of 10mm2 T&E and be non RCD protected. To be compliant to the regulations the cable had to run surface mounted and also get from one side of the house to the other. I worked out an initial route and ran it through with the electrician to determine the final installation run. The roof space was no problem as the cable is clipped to the main centre joist. To get to the new CU in the garage, the cable drops down through the ceiling within a bedroom cupboard and through the floor into the garage. A small run of surface mounted white conduit runs through here. To get from the roof space to the lounge it exits a gable wall and runs down the outside wall inside black conduit and back through the wall behind the new socket. All done neatly and unobtrusively.

Just for completeness for the OP, this is what I gave my electrician to explain what I wanted.

Why did it need to be a type C MCB?

Type C was recommended.  Mainly to stop nuisance tripping on switch on if i ever went back to a stack of Naim Kit. 

Steve Hopkins recommended using a Type C MCB to me. Turning on my power amp used to trip the breaker about 50% of the time, and since putting in the dedicated circuit with Type C breaker it has never tripped.