Don't cut costs on plug packs... - Page 1
Forum section: electronics / general

author: johnboxall
author_rank: Unknown
timestamp: June 16, 2010, 04:46:36 am
content: Today I received one heck of an electric shock, and lived to tell the story.Please read:http://bit.ly/djtoCOOf course it was my own silly fault for being a cheapskate, however still a timely warning to others out there.Have a safe dayJohn

author: comox
author_rank: Regular Contributor
timestamp: June 16, 2010, 06:28:06 am
content: There are lots of tales about counterfeit and poorly made power supplies for sale on eBay. Here is an analysis of a counterfeit Dell PSUhttp://www.electricstuff.co.uk/acadapter.htmlDon't buy this stuff!

author: johnboxall
author_rank: Unknown
timestamp: June 16, 2010, 06:50:09 am
content: Wow - that is spooky.From general experience and anecdotal evidence, eBay don't really give two hoots. Have ordered a couple of nice new plugpacks from Farnell this afternoon.Live and learn!CheersJohn

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 16, 2010, 08:10:31 am
content: Approval marks from Far East products are often applied fraudulently. This is by no means new. A few years ago, a customer of mine asked a Far-East supplier if they could supply transformers with a particular safety approval mark for a specific country.The reply was "No problem, just send us the artwork"

author: johnboxall
author_rank: Unknown
timestamp: June 16, 2010, 08:12:44 am
content: Quote from: mikeselectricstuff on June 16, 2010, 08:10:31 amCrikey.Someone on another board sent me this:http://www.electricstuff.co.uk/acadapter.htmlSame story.

author: cybergibbons
author_rank: Frequent Contributor
timestamp: June 16, 2010, 08:17:29 am
content: I had a small regulated wall wart that had a selectable output voltage 3/4.5/6/7.5/9/12V. I think I was only about 10 at the time, and I was using it to power my electronics lab kit (the thing with all the components mounted to it and the springs to connect it up). I was using it, and flicked the switch to change the voltage, and bang, a load of components were frazzled.Measured the output voltage and when the switch was in certain positions, you got mains on the output. Really dangerous.Informed trading standards etc. but never heard anything back.

author: johnboxall
author_rank: Unknown
timestamp: June 16, 2010, 01:24:17 pm
content: Quote from: shafri on June 16, 2010, 01:22:58 pmVery good advice Shafri.Normally I would turn it off at the power point first, but it was plugged into a powerboard which has my computer on it as well, so I foolishly just pulled it out without thinking. D'oh.

author: Time
author_rank: Frequent Contributor
timestamp: June 16, 2010, 02:30:09 pm
content: I was watching a colleague of mine play with some gas discharge switches. He was pointing around his high voltage PSU at the time while it was charged telling me a story about how 30 kV arced from a ground lead to his keys in his pocket and into his leg. As he was saying this and pointing, a huge arc off some field enhancing bolt threads holding another ground strap down jumped into the tip of his finger. This time it was 80 kV.It was scary for a second, than he jumped around screaming and cussing, than the irony and humor set in and we both got a good chuckle out of it.

author: Time
author_rank: Frequent Contributor
timestamp: June 16, 2010, 02:54:35 pm
content: Yeah the worst I have ever felt was grabbing a board plugged into the mains a few times. Kind of like a 'whats that tingley feeling? OH Im getting electrocuted!' haha

author: saturation
author_rank: Super Contributor
timestamp: June 16, 2010, 04:53:05 pm
content: I'm glad you came out ok.However I do buy and own a lot of those cheapie chinese plug packs, I think shipped to the USA it cost me $1 each delivered.It may be a problem if you are just a consumer, but if you have electronic skills, these are a bargain, its like hunting for reject parts from a factory, or salvaging components from the trash.Like Dave, you should take it apart to know what you get, so when you buy them get one that is screwed together, rather than glued.You'll find many of them are decently made, no worse than if I made it myself as a DIY kit, but I would be hard pressed to get the casing and wiring as ergonomic, or even the same parts for $1.00. Just the postage alone shipped from China would be more than $1.00. However, like many things I get from China, even better made or more costly, seem to lack something here and there, that if they just added, would up the quality quite a bit.For plug packs, many are not fused, so if they short your circuit breaker is your main protection against sparks and possible fire. If you are skeptical, just use these plug packs through a power strip or surge protector, which has the circuit breakers that can trip for you before the mains line.With the right equipment, you can test the specs of these AC-DC converters and add the parts needed to improve regulation, ripple, and protection.Derate them, if its rated for 1A, only use it to 500mA, for example. To insure you remember, fuse it with a much lower rated fuse than its operational capacities.For what you just experienced, and I have plug packs that look just like yours, don't pull the pack by its adapter, as you've already found out, because the terminals could still be in contact in your hand, disconnect the pack separately or glue or zip tie the adapter permanently to the unit since it looks like it has USA style plug, and you need the Aussie one.If you buy brand name items direct from China, they could be counterfeit. All the labeling should be considered meaningless without prior testing. You may pay extra for a fake brand name, but don't get the same quality control or reputation; you're better off getting the no-name and checking its specs.If you know what you pay for, and can troubleshoot it, its not a bad deal.Lastly, beware of chemical contaminants in the product itself. Since these are not made to be eaten or placed in your mouth like toys or food, its less an issue. If this worries you, just wipe it down with ethyl alcohol before you use it, that should remove all the superficial ones that you might get on your hands.

author: saturation
author_rank: Super Contributor
timestamp: June 16, 2010, 11:21:59 pm
content: Counterfeit items are a bigger problem than buying a no-name unit compatible with your laptop. If a maker is willing to deceive the buyer by masquerading as a Dell, there's also a good chance the electronics are equally masquerading its specs, and thus its rated power and even its basic safety.Quote from: comox on June 16, 2010, 06:28:06 am

author: EEVblog
author_rank: Unknown
timestamp: June 17, 2010, 01:11:02 am
content: Shit! glad to hear you are ok. Belts like that can knock you around for hours.I've seen those adapters too and think they are completely dodgy, I think they even came with some brand name gear...Dave.

author: PetrosA
author_rank: Frequent Contributor
timestamp: June 17, 2010, 01:15:52 am
content: From the sounds of it, you could have gotten the same shock with or without the adapter since it was a case of user error that caused it. It's not clear from the blog post whether you were using one hand or two or if you were barefoot at the time, but if current crossed your heart, that would have been bad - probably worse than what you describe. You were lucky this time, and remember to keep your fingers away from the working end of a plug

author: joelby
author_rank: Frequent Contributor
timestamp: June 17, 2010, 05:42:10 am
content: For what it's worth, my local Cash Converters (a chain of pawn shops) had a big box of pre-loved mobile phone chargers going for a couple of dollars each. These seem suitable for general electronics stuff at around 5V, 500 mA and are branded by Nokia or whomever. At least then you'll get an Aussie plug.

author: johnboxall
author_rank: Unknown
timestamp: June 17, 2010, 06:22:40 am
content: Quote from: joelby on June 17, 2010, 05:42:10 amWow - that's very interesting. I will stop by one tomorrow.Thanks,john