I’m a great one from buying gadgets from China – especially as their government appears to pay the post (many small items from China have free post – and the ones which don’t are a con anyway as they make the product cheap for duty purposes!
And that’s fine – except when it comes to safety. A friend of mine recently bought some MAC-like power supplies from China – wonderful little things about an inch square – with a usb connector on them – suitable for charging phones and powering little gadgets. He very kindly gave me a couple to play with and I put my phone on charge.
About 10 minutes later I heard a “puff” sound and the phone stopped charging. I threw out the charger and went off on business – but today I figured I’d take the unit out of the bin – and have a look see why it blew up.
Take a look at the image on the right… the two red wires are the mains wires inside the unit.. take a look at the gaps between the tracks for those wires and the rest of the circuit! That would be sub-1mm… WELL sub-1mm. For 240v this should be AT LEAST 2mm and personally I’d make it 3mm. We’re talking 250v LIVE here.
Think about that next time you find a bargain power supply…