ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Safe adapters

Some of the travel adapters sold really are of very poor design and build quality.

It's certainly a good point about using plug-transformers which these adapters. A European-to-British adapter already has quite enough weight hanging on the end of with just a standard BS1363n plug, nevermind anything extra.

I'm not a fan of these all-in-one plug and xfmr combinations that have become so popular. I'd much prefer to have the power pack connected via a regular cord and plug.

Certainly for travel needs, I much prefer a plug-cord-socket home-made adpater to the various combo units on sale.

Some of the newer mobile phone plugs are very neat & light weight whatever they're using to step down the voltage.

I just noticed a weird British connector product.. found an iron with a very old MK BS1363 plug complete with a switch on top of the plug!

Switched Schuko plugs are rare, but they do exist. I use them to cut power to wall warts without unplugging them. They're rather bulky angle plugs with a simple double pole key switch. Nice arcs.

Luckily, the heavy transformers will be gone in a few years. The switching mode power supplies are becoming cheaper and better.
They are lighter as there is no iron core in them. With sufficiently high frequency any material for the core will do. Many aftermarket power supplies sold in Sweden today are of this type. As they are made in China, I suspect it is not a local phenomenon.

But SMPS devices will not work well with certain portable radios or TV sets.

SMPSs toss out a lot of RFI....so I guess for these devices the transformer-based adapters will still be needed (unless they go back to incorporating the power supply inside the radio).

Sven,
this used to be a hurdle, but it has been overcome. The EU has strict limitations on the electromagnetic compatibility. Just about every after-market cell phone charger had to be taken off the market after a "raid" testing the compliance two years ago.

Time to bring this up again!

David had an idea about IEC connectors as an intermediate step in an adaptor. I gave it a little thought:

Here is the idea:

1.) A proper listed/approved local plug (NEMA, Schuko etc.) with grounded 10A 250V / 15A 125V IEC 320 connector on the other back.

You can buy this type of adaptor already:



These are compact compared to conventional adaptors.

2.) The second part is simply a conventional trailing socket with two or three sockets. Listed/approved of course. Instead of the ordinary plug, it has an IEC connector on the cord which mates with the adaptor.

3.) If you have a transformer this is simply connected between the adaptor and the trailing socket. It has a cord with a male IEC connector as input and a female IEC connector on the transformer itself where you plug in the trailing socket.

4.) There is an ungrounded IEC connector too, although rarely used. This should be used on ungrounded plugs. Either you use a trailing socket that only accepts ungrounded plugs or you add an ungrounded IEC to grounded IEC adaptor. It would simply consist of an RCD/GFCI and the connectors. Even with the RCD it can be made very small and robust.

The result? A system where the grounding can't be bypassed unless you have ground fault protection. In addition, you have two or three proper sockets to plug into. Lastly, the plug you insert into the foreign socket fits correctly and is lightweight.

As a bonus, you have a modular system that can be sold in any country of the world. Only one type of transformer is necessary for the whole world: 115/230V Step up/step down. (Still in different sizes, of course)

Ever see a modern Apple power supply for a laptop or an iPod or even their new plug-in wifi stuff.

A small figure-of-eight connector moulded onto a plug slots neatly into the top of the plug-in switch mode transformer. All looks very slick and neat and as you travel around you simply swap the plugs.

The nema setup: the BS1363 setup is bulkier looking!




Similar idea to the IEC adaptors though.

[This message has been edited by djk (edited 06-27-2004).]