Now why didn't I think of that?

[d000hg]

It's a very slick design, especially the way he has multi-plugs which accept the folded configuration - a 4-gang the size of a normal plug.

There are potential safety concerns but I can't see them being insurmountable, materials science has advanced a long way.

[conned tractor]

As sad as I am I had a think about the polarity issue whilst being frogmarched around around the shops.

If the load was inductive or resistive, i.e. a motor or light, then it wouldn't matter as a circuit is made across the load - apart from the fact that you would be switching the negative side - which is not necessarily a good idea since the item under load would remain on the live side.

However, if it was for example a power supply (probably most complex electrical goods) then it would matter and hence would not work.

The polarity only refers to the live signal though which alternates between +325 and -325 Volts. The negative is connected to earth at the substation and will be around a few volts potentially different to the earth pin.

However, I should imagine it is also possible to monitor and switch the supply around in the psu box of a product like this. And again as minestone said they would be better to reduce the size of the power supply box.

[blacjac]

If polarity was such an issue, why does nearly everything I own use a wire like this that can be plugged in either way round?

http://www.powersuppliesonline.co.uk...36/default.htm

[minestrone]

If polarity was such an issue, why does nearly everything I own use a wire like this that can be plugged in either way round?

http://www.powersuppliesonline.co.uk...36/default.htm

Go and change the polarity on your fan cooler and it will be blowing air out its arse.

Some items can deal with polarity changing, some cannot.

[swamp]

While our 3 pin design is arguably the best one in practical and safety terms it's too chunky and this design is a very elegant solution.

I always thought the UK plug was a crap design. Very painful if you tread on one in bare feet.

[Churchill]

Go and change the polarity on your fan cooler and it will be blowing air out its arse.

Some items can deal with polarity changing, some cannot.

On the polarity discussion above:

What a lot of twaddle.

Wot comes out of the wall is AC at 50Hz and 230V (allegedly).

The polarity of which reverses every 10ms.

So for 10ms, the Live pin is positive with respect to the Neutral pin.

Then for the next 10ms, the Live pin is negative wrt the Neutral pin.

Swapping the pins about does very little, other than giving you the possibility of getting a switched Neutral rather than a switched Live. (I last encountered a switched Neutral when trying to fix a tv in someone's house. The socket was wired up with bell wire. "We had a proper electrician to install the wiring, Mr, honest").

If you swap the Live & Neutral on a fan, it will still go round the way it did before. Coz it's still fed with AC.

Ditto with all the power supplies you may encounter.

None of it gives a rat's arse about which pin is Live or Neutral.

On the "swapping pins makes it go backwards" front, the only way you'd see that with AC is if the device uses a 3 phase motor and you swap two of the phases.

Which I have seen, on a CDC tape testing machine that I moved & then discovered that the socket I had to use had two of the phases swapped so that instead of the vacuum pump sucking, it blew.

Not a lot of use when it should be sucking tape down a vacuum chamber.

So much for your engineering qualification Minestrone!

[gingerjedi]

Knew it!

(Waited for Zeity to confirm though).