USB Charger Safety

[anon(10181084)]

I keep reading stories about small children and even adults dying due to being electrocuted by charging devices and even just by touching a frayed USB cable. They they say how you need to be "careful" when charging. By design you should NOT need to be at all careful with a charger as it should be properly isolated from mains voltage. But those cheap cube chargers from China (and similar junk) frequently have transformers with little to no isolation between the primary and secondary, and the distance between the PCB traces on the primary and secondary side (creepage distance) of the switching power supply is sometimes a millimeter or less (I took one apart last week https://youtu.be/_0i6UESoj2Y). Ideally it should be 4mm and for double isolated chargers 6.4mm. I own the very well built and super safe Ldnio A8101 (I was too cheap to buy Anker or Ravpower, and Aukey chargers like to melt down on a regular basis according to reviews). The A8101 has huge creepage distance and even a secondary trasformer winding WRAPPED IN INSULATION MATERIAL (see provided pictures). The design is top notch, which is to be expected for $20, and is a good example of how a quality high-performance charger is designed. And big-brand-name chargers are only $10 more expensive, so there is no excuse for getting garbage death trap chargers from eBay and back alley phone shops. I seriously do not get why the low quality Chinese junk exists when stuff like the A8101 can be made relatively cheaply and is much much safer. Think twice next time before buying a cheap charger in a gas station or dollar store, as you might be very close to mains voltage and could end up dead like the people in the news.

 

[mustang7757]

I keep reading stories about small children and even adults dying due to being electrocuted by charging devices and even just by touching a frayed USB cable. They they say how you need to be "careful" when charging. By design you should NOT need to be at all careful with a charger as it should be properly isolated from mains voltage. But those cheap cube chargers from China (and similar junk) frequently have transformers with little to no isolation between the primary and secondary, and the distance between the PCB traces on the primary and secondary side (creepage distance) of the switching power supply is sometimes a millimeter or less (I took one apart last week https://youtu.be/_0i6UESoj2Y). Ideally it should be 4mm and for double isolated chargers 6.4mm. I own the very well built and super safe Ldnio A8101 (I was too cheap to buy Anker or Ravpower, and Aukey chargers like to melt down on a regular basis according to reviews). The A8101 has huge creepage distance and even a secondary trasformer winding WRAPPED IN INSULATION MATERIAL (see provided pictures). The design is top notch, which is to be expected for $20, and is a good example of how a quality high-performance charger is designed. And big-brand-name chargers are only $10 more expensive, so there is no excuse for getting garbage death trap chargers from eBay and back alley phone shops. I seriously do not get why the low quality Chinese junk exists when stuff like the A8101 can be made relatively cheaply and is much much safer. Think twice next time before buying a cheap charger in a gas station or dollar store, as you might be very close to mains voltage and could end up dead like the people in the news. //uploads.tapatalk-cdn.com/20191108/5412a7011f6c6776e32d7f442264db45.jpg//uploads.tapatalk-cdn.com/20191108/3126b9dd07f68f6d9baf4a5ec44d16d3.jpg//uploads.tapatalk-cdn.com/20191108/6a32e020372779401c144ca74ac0c26b.jpg

I agree with you on this , thanks for posting.

 

[anon(10181084)]

I even put a nicely written PSA about the dangers of the cube charger right on the bulletin board across the hallway from the campus bookstore only to see it disappear the next morning... And the sad thing is these have been selling like crazy lately. I tried contacting the bookstore to no avail. And another reason I am so passionate about this topic is that I was actually electrocuted by a metal lamp that was leaking mains voltage at my grandmother's house when I was just a few years old, and it was with 220 volts and not the puny 110v that is a little bit less deadly. I am lucky that I only felt a strong tingle when touching the metal switch nob on the lamp and wasn't touching anything grounded... Bad chargers, when their isolation breaks down for some reason, will act like this and if your are with your phone in the bath tub you will be killed, and it is a big problem in places like Russia and Ukraine where they have no RCD protection on their home power, let alone GFCI sockets. If you want to check whether a charger you own is safe without tearing it down, have a look at https://lygte-info.dk/info/ChargerIndex UK.html . For example, some of the lower end Ldnio chargers are low danger and some higher, while a number of the higher end ones are perfectly designed and look comparably good to mine (I think mine is the highest end and best designed one). Heck, even the old Samsung 2amp charger (they type found with the Galaxy Tab 2) is not 100% safe.

 

[mustang7757]

I even put a nicely written PSA about the dangers of the cube charger right on the bulletin board across the hallway from the campus bookstore only to see it disappear the next morning... And the sad thing is these have been selling like crazy lately. I tried contacting the bookstore to no avail. And another reason I am so passionate about this topic is that I was actually electrocuted by a metal lamp that was leaking mains voltage at my grandmother's house when I was just a few years old, and it was with 220 volts and not the puny 110v that is a little bit less deadly. I am lucky that I only felt a strong tingle when touching the metal switch nob on the lamp and wasn't touching anything grounded... Bad chargers, when their isolation breaks down for some reason, will act like this and if your are with your phone in the bath tub you will be killed, and it is a big problem in places like Russia and Ukraine where they have no RCD protection on their home power, let alone GFCI sockets. If you want to check whether a charger you own is safe without tearing it down, have a look at https://lygte-info.dk/info/ChargerIndex UK.html . For example, some of the lower end Ldnio chargers are low danger and some higher, while a number of the higher end ones are perfectly designed and look comparably good to mine (I think mine is the highest end and best designed one). Heck, even the old Samsung 2amp charger (they type found with the Galaxy Tab 2) is not 100% safe.

Oh wow , consider yourself lucky .
In car industry I've had my fair amount of being zapped from spark plug coils 12v 3 amp primary side and up to 20,000 volts on secondary , not a good feeling lol

 

[anon(10181084)]

Back then in Serbia we didn't have at my grandmother's circuit breakers, but rather normal fuses. Also, most of the house except the kitchen and bathroom had no grounding even on the shuko sockets until a few years ago when we had her electrical installation redone. And as for personal experience with bad chargers, I actually had a cheap 500mA "courier charger" I bought for some small devices literally BLOW UP into sparks when after a few years when I plugged into the wall (this probably wouldn't have been as epicif it hadn't been for the high voltage in europe).

Edit: World-renowned YouTuber BigCliveDotCom has given me some facts about that charger I have that I used as an example of a good one.

Edit 2: Typo fix