Use of Schuko sockets in a UK home only for a HiFi system

Hello everyone,

This is my first post.

I have a question about using Schuko sockets in a UK domestic home.

But first, a bit of background might help.

I am a Member of the Institution of Mechanical Engineers. I didn't think my people would be very good at answering this question which is why I am here!

In more detail, I would like to use a Schuko socket to which only my hi-fi system would connect. The socket would be connected to a brand-new consumer unit with RCBO’s. There will also be surge protection. All will be done to the latest standards and specifications by a fully qualified electrician. The wiring diagram would be based on the one in this link: https://www.russandrews.com/images/pdf/MainsWiringGuide111023.pdf

I will also have a regular UK 3-pin socket. I am a reviewer for a HiFi magazine and want to do the above as the basis of an article on HiFi power supplies. 

So back to the question, is there any legal reason (or otherwise) that I can't use the Schuko socket in the UK? 

If the answer is “yes I can”, albeit with specific conditions, I'd like to quote that in my article/review. Especially if the Schuko supply sounds better than the UK 3-pin with fuse!

I am looking forward to your response.

Many thanks

Paul

  • Hi Paul and welcome! Slight smile You're definitely in the right place. 

    I think we've had a similar conversation in the forum before but I can't track it down. I'll link it here if I find it. 

    In the meantime though some of our forum members will no doubt jump in  Slight smile

    Lisa

  • OK, be prepared for some opinions on this one!

    Why a Schuko? Continental plugs and sockets don't have a great reputation for long term reliability. One of the design features of the 13A plugs over the earlier round pin variants was the advantage of having a flat contact area - it's much easier to maintain a good (low impedance) contact between two flat surfaces than between two rounded ones - for rounded ones to work well you need to match the curvature - which even if you get it precisely right in the first place (unlikely given manufacturing tolerances) they then change (typically in opposite directions) as the contacts wear. I can see that the omission of the fuse would reduce loop impedances every so slightly - but then I'm probably not convinced by the impedance of a.c. supply making much difference - surely the capacitors on the d.c. side of a properly designed audio PSU should be able to carry over any peaks and troughs in the audio demand - the mains supply drops to zero 100 times a second anyway, and no amount of fancy low impedance wiring is going to side step that.

    Schuko plugs aren't polarised (L-N can be reversed simply by inserting the plug the other way around) - for most modern appliances that shouldn't be an issue, but I wouldn't be happy using one to feed anything containing single pole fusing (e.g. a UK style 13A multiway socket into which fused 13A plugs would be inserted).

    Schuko sockets on UK installations are an on-going debate. BS 7671 specifies the use only of British Standard  BS 1363 (13A), BS 546 (old round pin UK) and BS EN 60309-2 (industrial style) for LV (main voltage) circuits, and further demands that they be shuttered for household use with a preference for BS 1363 ones. It does permit an exception to the first bit though for "a circuit having special characteristics such that danger would otherwise arise or it is necessary to distinguish the function of the circuit" - it depends on whether you can convince your electrician that you HiFi falls into that category. Any unfused socket will have to be on a suitably rated circuit though - 13A sockets are only permitted on 32A circuit because of the plug fuse -  for Schukos the circuit will have to be downrated to 16A (or maybe 20A).

    If it's just the fuse that's the issue - a UK style unfused round-pin socket (e.g. the old 5A or 15A ones of yesteryear) are still permitted and available and might be a more obviously conforming solution (plus are polarised).

    There are a few other things that don't quite ring true in that guide though. The wiring of the extra CU into the meter tails in the way they describe means the installation not longer has a single "main switch" that reliably switches off everything - usually held to be contrary to BS 7671 reg 462.1.201. The choice of a ring is 'interesting' - in other situations were mains borne noise is an issue radial circuits are normally preferred (to prevent the "loop" of the ring acting as an aerial). Running both legs of the ring together throughout the run reduces that effect, but a single cable is typically simpler and easier. Screened mains cables (e.g. BS 8436) can reduce interference pick-up too. On cables, their "woven" offering I suspect will cause all sort of problems with BS 7671 compliance, not only in terms of standards compliance (required by BS 7671) but it's construction of many separately insulated strands will cause all sorts of technical issues with short circuit protection. Even their description of what needs RCD protection seems to owe more to urban myth than wiring regs. Expect that your electrician will want to alter things a bit (with additional costs no doubt).

       - Andy.

  • yes you can, but it won't comply exactly with BS7671, so many electricians will wobble at that as it makes it hard for them  to 'sign off' .

    For minimal hassle it can be done in a way that later converts back to a UK socket when you move house or whatever.

    Note that to be fully  representative of say German practice, really it needs to be on a 16A radial circuit, all the way back to the board and wired in cable with a full size CPC (earth) . However, in reality being fed from a 13A fused spur from the same sort of ring as all your other sockets will probably do just fine.

    Mike.

    Edit, that Russ Andrews doc is quite a laugh - beware there are a lot of snake oil merchants in Hi Fi, but I'm sure you know that..

  • I think it will also help to understand what you wish to achieve. Do you just want to be able to test/review continental equipment without having to replace the plug in which case a Schuko socket strip with a 13A plug fitted would be sufficient? If you are trying to compare the effects of UK and continental mains supplies there are a lot of differences to consider including the use of lower rated three phase supplies to the continental buildings.

  • snake oil

    I was diligently trying to be polite by avoiding that phrase! It is amazing what they can re-sell a £10 Berker caravan 13A socket for though...

      - Andy.

  • Thanks Mike.

    My Electrician said he's happy to sign it off because nothing else can be plugged into it, e.g., a lawnmower going outside via an extension lead.

  • Going off on a bit of a tangent (sorry!) - I was intrigued by the mention of "balanced mains" in that .pdf. Turns out they're recommending units with a transformer that supplied 115-0-115 rather than 230V. (https://www.russandrews.com/balanced-mains-units/). I presume the centre tap of the secondaries are earthed - so presumably that's defeated upstream 30mA RCD protection to the HiFi sockets....

       - Andy.

  • Good - that is helpful.  I have found that the basic ones

    https://cpc.farnell.com/pro-elec/pe5100/schuko-socket-1-gang/dp/PL01821

    are a pretty good fit to a single deep UK back box. The sort of cable you want to represent normal German practice would either be stranded singles in flexi tube or sheathed  NYM-J 3 x 2.5 mm²  or similar.

    M.

  • "I think it will also help to understand what you wish to achieve.."

    I'm looking to compare a regular UK 13 amp socket fed from the normal house consumer unit with normal cabling, to another "HiFi" consumer unit wired in parallel with no fuses in the circuit, hence the Schuko. 

    Everything from the HiFi consumer unit to the Schuko socket will use "Audiophile-grade materials.

    In the nicest possible, most respectful way, I'm trying to avoid any discussions here on "snake oil". I just need to know from this peer group but I'm not doing anything wrong concerning safety.

    Thanks

  •   This is the previous conversation from before:  Installing a French electrical socket in a UK house?  Slight smile