Dodgy House Wiring...(Refugee)

[Terry]

Radial circuits with 32A MCBs and 4mm cable need no more fuses/breakers than ring circuits. Radials with 20A breakers and 2.5mm cable might need a few more than with rings.

I'm conjuring up a mental image here of the practice I've seen in modern European hotels of small Consumer Units high up on the corridor wall outside each room containing an RCBO (presumably) and four 16A MCBs for the radial sockets.

The flexibility of our ring main system has served us well for 70 years - not bad for an economy measure devised because of a copper shortage after WWII - and it is surprising that this is one area of our lives that the EU hasn't tried to tamper with!

To my mind, the downfall of the entire system is that I have never seen simple instructions about how to handle the part of the system that, until the widespread introduction of moulded Plugs and cord sets, has almost entirely been at the mercy of the end user - the 13A plug and flexible cord.

Ask the average person what fuse to fit in a plug and you will usually get one of two answers: it's a 13A plug, so fit a 13A fuse or the more thoughtful might suggest that it should match the load. Of course, neither answer is correct!

Equipment protection is down to the manufacturer. The plug fuse rating is to protect the flexible cord against current exceeding its rating and for no other purpose as I'm sure you all know ...

Manufacturers are not blameless in this respect, either. In 1967, two apprentice electricians were tasked with delivering a new Baird M700 colour set to a customer. They returned to say that the set was dead! When I investigated I found that, possibly overawed by the 279 guinea price tag (~£5,000 in today's Mickey Mouse money!) they had taken the trouble to fit a 5A fuse in the plug. The set, of course, was fitted with the usual thin twin flex which might have been rated at 5A although more likely 3A!

Fine for the normal operating load but the mammoth switch on surge, which included the degaussing circuit as well, of course, obviously exceeded this by a very large amount!

So, an over-rated fuse went into the plug and I started degaussing the badly magnetised tube!

Nothing like this on the other side of the channel, of course, where the unfused 2.5A 2-pin Europlug is specifically designed to mate with the usual 16A socket!

[ppppenguin]

Ours is the only major plug/socket system in the world with fused plugs. Don't know if any have fused sockets. The point is that a 32A fuse/MCB just won't protect a lot of thinner flex against a short circuit. A 20A MCB will do this, which is why they don't need fused plugs on the continent where 20A radials are the norm.

I emphasise short circuit protection, where the fault currrent is high enough to blow the fuse almost instantly. Overload protection is a trickier business. If an appliance is taking too much current it's the job of it's own internal fuses, thermal cutouts or whatever to disconnect it before things get too hot. The MCB in the distribution board can't do it, the plug fuse isn't meant to do it and is unlikely to.

[Terry]

I'm surprised that there doesn't seem to be any control over the quality of electrical accessories - principally adaptors - sold in the UK.

I'm thinking about things like this:

   
sold to tourists visiting the UK and returning holidaymakers with stuff fitted with foreign plugs.

As the socket isn't recessed there is nothing to stop the unsleeved pins of a plug becoming exposed and, of course, no provision for the earthing arrangements of French style and Schuko plugs, yet I've seen identical adaptors in Pound shops and, at around ten times the price, on the Travel Accessories rack at a local Supermarket chemist.

Yet there are well made adaptors complete with a good Schuko socket like this:

   

available quite cheaply on-line but never in the High Street - why?

There is one of these permanently plugged into a socket in our kitchen which we use for the Coffee Machine we bought in Belgium - it has never seemed worth the effort to cut off the moulded Schuko plug and fit a 13A plug (and the adaptor is also occasionally used for other odds and ends).

[ed731pdh]

Had similar issues with a lead French simulator company who did a job for us in the early 00's. The grief trying to get the proper sockets for the spec'd kit to interface to the UK power supply. In the end they bought a bundle of continental extension bars, cut the continental plug off and fitted a 13a UK plug.

[Terry]

Probably wasn't as easy to get them on-line in those days!

Actually, that was the best way of doing it.

Way back in 1980, a colleague and I were on our way to Kortrijk to carry out acceptance testing on some special viewdata receivers that Barco were producing for us. I persuaded my colleague to divert via a supermarket where we bought a plug and did exactly the same thing!

[Terry]

Incidentally, when I was at ntl: installing kit for the original digital roll-out, we used Barco up-converters to convert IF to Signal frequency.

Inside each box there were three IEC mains leads - one with a moulded Schuko plug, one with a 13A plug and another with a US plug.

I fitted a couple of Schuko leads to UK four-way blocks to use when we went on holiday!

[ed731pdh]

Best way deffo. The factory acceptance tests in France were fine, as everything interfaced directly to their power network with no issues.

The fun started when they came over to kit out the control centre.. oiks!

[Refugee]

I have got a "doggy" adapter like the one in post #13 that looks even more dodgy with the pins even closer to the edges.

I have been doing some "bombing out" and a can of worms was revealed.
A dodgy kitchen fitter has moved an already poor socket and then never managed to get it far enough so still ended up cutting a jagged hole in the side of the kitchen unit anyway.
I am not looking forward to opening the can of worms above the Bakelite consumer unit though.

[Terry]

I have got a "doggy" adapter like the one in post #13 that looks even more dodgy with the pins even closer to the edges.

That is really weird as, apart from the clearance issue, it looks as if it accepts a 13A plug, amongst others, which is a bit pointless!

The really damning feature, though, is the lack - as far as can be seen without dismantling it - of a fuse.

I don't know if the adaptor I showed has a fuse or not as it was one I found at random - on ebay, I think - and there was no picture of the other side.

Like the one I showed, there is no provision for earthing any type of European plug.

Incidentally, I came across a version of the good adaptor I showed in a French supermarket which was designed to accept the French/Belgian plug with the earth pin in the socket. The recess also needs to be completely circular without the guides for the Schuko plug. I was surprised at how ugly this one appeared by comparison as the Schuko version, to my mind, looks quite elegant in use. As all appliances these days are fitted with the moulded Schuko plug that fits either type of socket, the French style would only be needed if the traditional type of hand wired plug were fitted, so I doubt that there is any real need for such an adaptor!

[ppppenguin]

The Germans and French have done a pretty good job with their respective plug/spcket systems. All recent plugs will fit either socket which is good. I can imagine there are still some older appliances with specifically French or German plugs where you would need fit a new plug or use an adaptor when moving to a country using the other system.

When I went to Italy a couple of years ago I noted that Schuko is gaining ground there. I saw a lot of sockets that could take either Schuko or the old Italian plugs.

The map in this article shows how the German Schuko standard dominates in Europe. https://en.wikipedia.org/wiki/Schuko