greenalien Posted October 7, 2011 Share Posted October 7, 2011 If you use a powered USB hub, check the power supply - there are some Chinese imports, not CE marked, that can overheat, catch fire or explode without warning. They are marked 'Model KS868' AC110-240V 50/60Hz DC5V 500Ma I got mine with a cheap USB hub bought from Ebay - definitely a case of 'Buyer Beware!' Luckily I was in the room when it went bang and blew a lump of burning plastic across the room; others may be less fortunate. Link to comment Share on other sites More sharing options...
bigclive Posted October 8, 2011 Share Posted October 8, 2011 Many of the cheap Chinese USB type supplies are hazardous. I had one explode forcibly in my hand when I plugged it in, leaving a skidmark on my hand that matched the outline of the case. Electrical isolation between the input and output of these things is dubious to say the least, and when they go bang the whole interior can momentarily be at absolutely any voltage. Link to comment Share on other sites More sharing options...
sleah Posted October 8, 2011 Share Posted October 8, 2011 Maybe wise to plug the things in to the mains before connecting the LV end. At least if it goes the moment it gets the mains, it won't instantly destroy whatever you're using it to power ;) Link to comment Share on other sites More sharing options...
KevinE Posted October 9, 2011 Share Posted October 9, 2011 not only USB hub psu's but allsorts of wallwarts including mobile phone chargers. trading standards Link to comment Share on other sites More sharing options...
bigclive Posted October 9, 2011 Share Posted October 9, 2011 To quote... "We have found that there are approximately 1.9 million UK online sales of replacement chargers a year. All of the unbranded chargers that we have had tested have failed in respect to potential electrocution and overheating. Other authorities are reporting similar findings." Yup! Welcome to ebay. The home of directly imported dodgy tat. On a plus note, it's made the humble charger much more exciting than it used to be. :** laughs out loud **: Link to comment Share on other sites More sharing options...
johnlinford Posted October 9, 2011 Share Posted October 9, 2011 It would be nice if the Trading Standards page gave some tips on a practical way of detecting these dodgy imports duing regular inspections. Other than lack of CE mark, does anybody have any thoughts? Link to comment Share on other sites More sharing options...
Simon Lewis Posted October 9, 2011 Share Posted October 9, 2011 It would be nice if the Trading Standards page gave some tips on a practical way of detecting these dodgy imports duing regular inspections. Other than lack of CE mark, does anybody have any thoughts? I think that that's the point - these devices are often CE marked by their manufacturers. If the CE marking came about via independent inspection and verification, there would be some hope that the design had been tested. Of course, it doesn't stop the unscrupulous manufacturer simply copying the approval details of a good design! Link to comment Share on other sites More sharing options...
bigclive Posted October 9, 2011 Share Posted October 9, 2011 It's hard to tell the difference between a safe and dangerous PSU (or any mains product) unless you open it and know what to look for. Even then, some are well built but completely lacking in proper testing of vital components like the tiny isolation transformer inside. As Simon says, they often carry CE and other test marks and QC stickers that have just been applied routinely without any actual testing. I'd wager that even some of the high profile brands have safety issues too. You just can't squeeze 230V and 5V into a cube less than one inch square without compromising safety clearances. A good loud mains bang is much larger than one inch square. :D Link to comment Share on other sites More sharing options...
peternewman Posted October 10, 2011 Share Posted October 10, 2011 I'd wager that even some of the high profile brands have safety issues too. You just can't squeeze 230V and 5V into a cube less than one inch square without compromising safety clearances. A good loud mains bang is much larger than one inch square. :DI'm both amazed and worried by the new Apple chargers, the same size as a 13A plug, if not shallower, but remove some of the volume to include a USB A socket and there can't possibly be much space left at all, let alone everything else that has to fit in there. Mind you, given how quickly their cinema display PSUs seem to go pop, its probably just all crammed in very, very tightly. Link to comment Share on other sites More sharing options...
callumb Posted October 10, 2011 Share Posted October 10, 2011 I'd wager that even some of the high profile brands have safety issues too. You just can't squeeze 230V and 5V into a cube less than one inch square without compromising safety clearances. A good loud mains bang is much larger than one inch square. :DI'm both amazed and worried by the new Apple chargers, the same size as a 13A plug, if not shallower, but remove some of the volume to include a USB A socket and there can't possibly be much space left at all, let alone everything else that has to fit in there. Mind you, given how quickly their cinema display PSUs seem to go pop, its probably just all crammed in very, very tightly. Clive, That could be something for you to dismantle and show off the insides of one of those. http://www.blue-room.org.uk/public/style_emoticons/default/laugh.gif See how "safe" they are. Link to comment Share on other sites More sharing options...
Dj Dunc Posted October 10, 2011 Share Posted October 10, 2011 Question: When looking to buy lots of chargers (5v 3amp specifically) at about 100 per year, where do you look, and what suppliers are deemed to be reliable sellers of good quality stuff that doesnt break the bank. (Other than CPC / RS / Canford)? OEM and China imports were my first thought, but now Im more concerned about QC and reliability. Dunc Link to comment Share on other sites More sharing options...
sleah Posted October 10, 2011 Share Posted October 10, 2011 Question: When looking to buy lots of chargers (5v 3amp specifically) at about 100 per year, where do you look, and what suppliers are deemed to be reliable sellers of good quality stuff that doesnt break the bank. (Other than CPC / RS / Canford)? OEM and China imports were my first thought, but now Im more concerned about QC and reliability. Dunc Realistically, you should stick with CPC/RS etc. At least they have some degree of moral standards (even if just to maintain their reputations!) and you have someone to shout at down the phone when it goes wrong, who will eventually put things right. No such luxury with 'box shifters'. Link to comment Share on other sites More sharing options...
Brian Posted October 10, 2011 Share Posted October 10, 2011 Question: When looking to buy lots of chargers (5v 3amp specifically) at about 100 per year...I'd avoid no-name products like the plague for two reasons... 1) The PSU is often the most safety critical part in a product. 2) It's also the part most likely to fail. I'd reckon 80% or more of equipment failures are down to PSUs. Drop me a PM if you want and I can probably recommend a few OEM suppliers of decent product. Link to comment Share on other sites More sharing options...
timsabre Posted October 10, 2011 Share Posted October 10, 2011 Question: When looking to buy lots of chargers (5v 3amp specifically) at about 100 per year, where do you look, and what suppliers are deemed to be reliable sellers of good quality stuff that doesnt break the bank. (Other than CPC / RS / Canford)? OEM and China imports were my first thought, but now Im more concerned about QC and reliability. I would recommend PowerPax and Ecopac Power for this sort of thing. Good quality but cheap, and also very helpful if you have any trouble. Link to comment Share on other sites More sharing options...
greenalien Posted October 10, 2011 Author Share Posted October 10, 2011 I have to say, I wasn't looking for a power supply, I was looking for a USB hub - I didn't even think about the PSU, just plugged it in and used it. If it had failed immediately then it would have been less dangerous than what actually happened, with it working fine for a couple of weeks before going bang. Anyhow, I've put some pictures here On Picasa in case anyone's interested. Link to comment Share on other sites More sharing options...
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