http://www.electricstuff.co.uk/acadapter.html

We seem to be getting a lot of these junk power units now.

There were some ofthe "wall wart" type a few years ago in which the transformer primary was wired straight to the plug-prongs -- No fuse or even overtemperature cut-out. So on the typical British ring-circuit outlet, there could be no more protection than a 30A BS3036 rewireable fuse!

Interesting research done there.

See what a rip off market some products have become with no care about safety in mind.

Those wall warts behind computer desks, when improperly made, like the one shown will add to the risk of fires and premature faillure of the latter.

I own a Dell laptop and my PSU/Charger is rated at 65W.
It charges the battery in the laptop well enough.
If you own a Dell computer, there is a link on your Start menu that will send you to find out if your gear is genuine.
That is how I found out that my battery was suspect.
NZ$106 later I have a new battery and all is well again.
However, the power supply that came with this laptop, seems to be "potted" into a solid block.
Therefore, any chance of repair would be pretty remote.

There was also that unfortunate lady in the Netherlands a few years ago who purchased a fake Nokia battery and it exploded when she was talking on the phone doing pretty serious injury to her face and hand!

There's a lot to be said too for manufacturers not over-charging for simple things like batteries and AC adaptors. I know the likes of Sony and Apple charge ridiculous amounts for theirs.

Paul what is the usual setup for a "wall wart" with UK-pins ?
Is there a fuse?

Over here, they'd be less likely to end up on a 30A fuse, but even so I woudln't be entirely happy with a 16A or 20A circuit either.


[This message has been edited by djk (edited 12-17-2006).]

About 20yrs ago I had a transformer type of adaptor (called Plugpacks locally) which quietly melted while in use. Just as well I was there. And another one had insulation failure...I received a rather unpleasant shock from what would normally be just a 6VDC supply. Turned out the secondary was wound over the primary; not separate insulated bobbins on the transformer. So, no I don't trust them.

Indeed, but sometimes there are recalls of fauly batteries and then they're really nice. My iBook battery was affected, and within 3 weeks I had a new one completely for free.

The power adaptor for my external hard drive is an ugly beast. It delivers 18A @12V DC (switching supply), and guessing by how hot it get's (even when the drive is off) I guess it dissipates the same amount as heat... I only call it the "heating resistor" and unplug it whenever not in use...

There should be -- A common arrangement seems to be for it to be mounted on a small PCB, the latter also having either spring connections or small wire loops to the L/N pins at the bottom of the unit.

Transformers types of adaptor these days have a thermal fuse embedded under the outer insulation of the primary winding. It often goes open circuit for no reason. Replacement fuses are available for those that want to dig out the old one. Naughty people just bridge it out.