New electrical system planning

Electrical installation vary widely in different countries. The UK is unusual in that wall sockets tend to be connected in a ring, where a cable runs from the main board to one socket, then to another, and another, and eventually back to the main board. So it’s shared between multiple outlets, often in several rooms. This requires a heavier cable and a higher rated circuit breaker.
A radial circuit usually runs to a single outlet, so may only need thinner cable and a lower rated breaker, but of course you need more of them to cover a whole house. This is standard practice in most countries, probably including Italy but I’m not certain of this.

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Hi, that’s actually not quite right. The point of a ring main is to safely allow the use of thinner cable (2.5mm2). Each socket has 2 paths back to the circuit board and breaker, so 2 safety earth paths and 2 pieces of wire to share the electrical loading. With a radial you will usually find a number of sockets run in a chain, so the first bit of wire carries load from all sockets, the next bit a bit less, the next less still. The upshot of a radial is the first bit of wire carries more load and actually needs to be thicker (generally 4mm2 or more). A radial on a 2.5mm2 cable would be limited to a 16amp breaker, not the more common 32amp. Phil


Unfortunately that isn’t quiet right. In the UK a mains ring is wired in 2.5mm squared. Now 2.5mm is rated at 16amps, but because you are feeding each socket from 2 ends of this cable, the whole circuit can be rated at 32amps. If you wanted 32 amps on a radial, then you would be looking at wiring in 4mm, which is what often happens in Kitchens these days. In the case of a HiFi circuit I think the idea is to go with a bigger cross section cable to have a smaller resistance (imagine the difference between a small water hose and a big one). So 6mm or even 10mm will be even lower resistance than a normal ring or radial. The cable itself will have a very high amperage rating, but for a HiFi circuit, I would suggest 32amps is more than enough

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oops - SNAP :blush:

I understand your point, but non-UK wiring I’ve seen (US and France) seem to have large numbers of very lightweight circuits with skinny cable and low spec breakers. The latter would be needed when there is no UK-style fused plugs to protect individual appliance leads.
Either way, my point is that what we may suggest based on UK practices may often be inappropriate in Italy.

absolutely :blush:

Today I had the chance to speak to my Naim dealer. He suggested me to go for a good quality 16 amp cable (the kind of cable used in Italy for home appliances). At this point it seems that I shouldn’t worry too much. However I won’t forget about a proper dedicated earthing and an audio grade wall outlet too.

Surprising, I assume Italy is 230V, so that would probably equate to 2.5mm cable like the UK, which doesn’t match up with other advice people have been given on this Forum. I think I would be inclined to check with another Naim dealer if possible.

In theory all of Europe as it was a year or more ago normalised their electrical standards around IEC 60364, so the science behind the UK and European electrical system should be the same, it is the application which may differ.

The historical reason why the UK use ring circuits, is because it saved the industry copper which was a precious commodity after WWII and to save money!

Radials can have just one load point but quite often they have more than one load/sockets. UK lighting circuits are wired as radials (so we are able to do it!) and nearly always serve more than one lighting point. If this wasn’t the case we would have a lot more MCBs/fuses back at the consumer unit.

In my experience Radial circuits are almost exclusively used in domestic systems in main land Europe, they are easier to fault find and avoid the risk of the user inserting the wrong plug top fuse for the appliance flex. Rings have one particularly unfortunate issue, if the ring is open at any point, say due to poor installation or damage, the protection is no longer adequate to protect the typical 2.5mm2 CSA T&E cables used. Of course regular inspection should pick up faults, recommended interval between tests no more than every 10 years! Ha, and few have this carried out!

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Yes here it’s 230V / 50Hz, I just checked it. I also checked what kind of cables might be available here in Italy. 4 mm² / 25 Amp and 6 mm² / 32 Amp should be easy to get. But it could be easier than I thought to get a 10 mm² cable as well. I need to talk to my electrician to sort this out too.

Also I was wondering… if my inverter will happen to be noisy, would you suggest anything to isolate it from the Hi-Fi dedicate line?

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A balanced power supply is a little black box you can install at the consumer unit end, but I suggest trying without first. My inverter doesn’t seem to cause an issue. Or of course if you are like me, you listen more intently to music at night, and therefore not an issue

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You are right, I almost forgot it sorry. However no rush, I’ll try how things go without a balanced power supply. If the system sounds bad or not good enough, I’ll surely have a go with that. This will surely take some time as the room will be totally different as well and a proper setup will be needed.

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