Dedicated mains - Survey

I’m not aware of any equivalent of that in the UK (apart from perhaps a hydra)?

I recently removed my Naim plugs from an Isotek power board and stack them using tapon plugs: 250/SC/555PS and it is much better - more dynamic and engaging.

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If that is AWG (American Wire Gauge), which is a reference common in many countries, it is approximately 3.3mm^2?

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Google says 12 AWG is 3.3mm2.

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I only hear good things about Tapon plugs in hifi.

Structurally, the Tapon stack is like a single electrical source point for your main power components.

Have you ever heard of an equivalent of this in the UK?

The closest I can think of is a hydra cable.

Interestingly Google finds a variety of mm^2 sizes for 12 AWG. The first I conversion I had picked up was 4, while looking further I can see 3.31, whilst another says 2.32mm diameter, which calculates to 4.23 mm^2! Thishighlights the risk of a quick “Google” in place of proper research. Clearly to be definitive one needs to go to ASTM or whichever US body sets the standard, however the consensus of quickly found tables appears to be 3.31, so 3.3 is best call, midway between 2.5 and 4. Guessing, the table I saw was possibly suggesting the nearest standard metric cable to use where AWG is specified, so 4 would be appropriate if the required is 12 AWG, but for the purpose of this thread 3.3 is the cross sectional area used assuming NZ gauge is the same as AWG.

I’ve amended my post that said 4.

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No, I haven’t, other than any power block that has star earthing. The big benefit of the Tapons is the direct connections on the three pins (P/N/E) to the wall socket, hence minimising joints in the power supply.

I’ve currently abandoned trying to get a direct spur. The fuse box is the 1960’s original, but I’ll take another look in it when I have an electrician round next. The music room itself is on a NZ linear feed to several power points via an RCD and was all newly wired with standard domestic cable about 7 years ago when the room was renovated for an office. I do have a few surge protectors for computers on the same feed and have been meaning to take them out to se if it changes anything thing. Off course, we had a major thunder storm yesterday,

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I’m assuming the Tapon plugs don’t have fuses ?

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No fuses on the Tapons, or any NZ plug for that matter. I’d speculate that theoretically you could wire in a NZ wall socket and put Tapon’s on your plugs, and use RCD protection in place of socket fuses….

I suspect that would not be allowed here in the UK. I was just thinking apart from the common earth, the other benefit is the lack of plug fuse for each piece of equipment with the Tapon.

PS - I’m not suggesting removing fuses from UK plugs, which would be a daft idea !

Yes absolutely! I remember decades ago when people were just beginning to cotton on to the relevance of mains supply seeing recommendations to replace fuses in 13 amp plugs with heavy gauge copper wire soldered across the fuse holder, which is clearly insane.

However I believe that round pin 15 amp plugs and matching sockets are still available for sale in the UK. These plugs do not incorporate a fuse. I am not advocating their use in any way because it seems to be a safety compromise but I have heard of some people using them for hi-fi and reporting good things. Also I have seen pictures of hi-fi installations using industrial 32 amp plugs/sockets which again do not incorporate fuses.

I have no idea of the legality of these plugs/sockets used in a domestic installation. Common sense tells me that they are a safety compromise which for me automatically rules them out.

Definitely permitted in the UK, but…

The circuits which serve 15A round pin and 16A BS4343 Industrial plugs and sockets are fed by 16A or 20A protective devices up stream and not the common 30/32A for ring mains, hence the electrical protection is in the consumer unit only, much like everywhere else in the world!

BS 4343 plugs and sockets are very common practice in data centres and other resilient supply environments.

One other proviso, the flex from the plug to the appliance has to meet specific requirements.

I have 5A round pin plug sockets in my home, for lighting, no fuse in those either, these are backed up by 6A MCBs.

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Besides regulations and practicality, I’m not sure safety is a huge concern as the UK is the only country in the World that uses fused plugs AFAIK?


After reading lots of positive comments and practical wisdom from the members of this forum about the potential benefits of installing a dedicated mains radial I finally did so three years ago.

It soon became clear that living in a second floor apartment would inevitably involve some compromising on the ‘ideal’ recommended installation and I soon abandoned the idea of running a dedicated earth to ground.

My supply uses a single 10mm2 radial (quite a long run of over 15m) to a Henley block next to the socket locations behind my system, then from there to three unswitched double sockets. see photo.

So to answer the question:
1. 15 years old.
2. No but 50 amp type C MCB.
3. 10mm2 T&E.
4. Three unswitched double Crabtree sockets. Wired as star.
5. And now the important one! Despite the obvious compromises from the ideal set-up, I was really pleased with the reduction in system noise and overall improvement in sound quality. I am not technically minded but I assume that these benefits come from the the thicker cable and the absence from the radial of any domestic appliances.

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The purpose of the fuse in a plug is to protect against fire caused by, for example, a short circuit in tge equipment, or damage to the flexible lead (cable) wired to the plug, that cable typically having a lower current capacity than the fixed mains wiring. To be fit for purpose the circuit breaker (not RCD, which serves a different purpose - though you can get an RCBO which combines circuit breaker and RCD) has to be sufficiently low a trip value to break the circuit before the short circuit or overload current causes the cable to catch fire, which means it must be chosen to suit the thinnest wire in the whole circuit. In Britain the mains wiring has a high power capacity relative to connected devices, with a high circuit breaker value rated for the fixed cabling, allowing multiple things to be connected to sockets. That wouldn’t provide adequate protection for, say, a connected cable of, say 0.75mm2. To give full protection using that cable the whole circuit would need perhaps a 3A circuit breaker if no fuse in the plug - in UK a 3A fuse is fitted in the plug, and the circuit has typically a 30A breaker.

That was my understanding and the reason I believe that no fuse in the appliance plug = a safety compromise. The MCB in the CU is of too high a rating to protect the flex to the appliance - that is what the fuse in the plug is for. When round pin plugs were common in the UK, decades ago now, that was the situation. But things have improved.

Something else that perhaps someone could enlighten me on. It’s been some time since I’ve owned Naim electronics but when I did the standard power cords supplied were all 0.75mmsq. However, the plugs on these were fitted by Naim with 13A fuses. This means that the fuse in the plug is not providing adequate protection for the power cord, which requires a 5A fuse in the plug. I understand Naim’s reasoning - that lower value fuses will fail prematurely due to transient current demands - but how does this square up from a safety / legal point of view - and are there insurance implications? If one were to have an electrical fire and the insurance company became aware that you had mains leads fitted with fuses providing inadequate protection then how would one stand?

Worked a charm for my then-Olive system. Stock Naim power cables hydra-ed into a fuseless 15A plug, straight to wall. We have the fuses in Naim equipment, and the MCB and RCCB to protect against surges… one too many fuses already - less is more. :upside_down_face:

I probably ran “happy “risk”” in this manner… but it just sounded so good.

Very good point. 0.75mm is only rated for 6amps

But that would be rated for 6A continuous which is way beyond what your typical Naim power amp would need in normal operation. The cable itself would survive the higher current (say due to a short circuit) for the time taken for the 13A fuse to blow.