Hi all I have done a fair bit of googling and I know this has probably been discussed to death all over the internet. I have discovered an article about a child in India had died from a phone charger.

https://www.google.com/amp/s/www.th...r-india-electrocuted-phone-charger-mouth/amp/
I know they say around 200mA could be deadly but I remember doing the exact same with a 9v charger with more than likely in excess of 200mA output when I was younger and I am still alive! It just tingled my tongue!

My point is the current would surely take the shortest route from the terminals on the plug so would only potentially hurt the localised area an not go anyway near the brain/heart?

My take on this is that maybe the charger was faulty and it was mains ground reference voltage at the plug end?

Anyone else have any theories?

Thanks

 

This does not sound believable ...could be an accident , or murder the parents are trying to cover up ..

from your link ..."
It has not been confirmed how old the child was, and whether it was a girl or a boy.
The two local respected newspaper's cite different ages and genders for the toddler.
In one report, the horror incident involved a two year old girl.
And in another, it was a three-year-old boy involved in the incident

If they can't even agree on the age or sex of the child how reliable is the rest?

 

I would strongly advise against putting the dc output of a mains charger unit in your mouth.

With no fault in the charger and it being built to recognised safety standards, there is minimal risk of electrocution.

As part of my work I have conducted market surveillance activity on direct plug in charger units sold within the UK. Of nine tested, eight failed a routine electric strength test applied between the mains input and low voltage output circuits. By using one of the failed units you would be at risk of electrocution; placing the dc output in your mouth would be risky in the extreme.

 

My chargers are UL/VDE/CSA certified. So it should be safe. In all the factories I have seen we test every thing. 100% of the power supplies get a "hi-pot" test.

Some companies, to save money, self test for safety. We always had a outside company retest before we summitted to UL. Probably in China there are companies that don't understand safety. They stamp UL on the charger when it is not. If it cost any to test every supply they might not.

I find it hard to believe 9/10 chargers fail power line isolation tests. This would kill people every day. How may of us have the phone charger next to the sink?

 

Hymie, out of curiosity how is this test conducted?

Do they increase the voltage on the mains input side until the isolation has broken down?

What is the standard in the UK for a pass before isolation breakdown? Or is that a massive open ended question?

 

Hi all I have done a fair bit of googling and I know this has probably been discussed to death all over the internet. I have discovered an article about a child in India had died from a phone charger.

https://www.google.com/amp/s/www.th...r-india-electrocuted-phone-charger-mouth/amp/
I know they say around 200mA could be deadly but I remember doing the exact same with a 9v charger with more than likely in excess of 200mA output when I was younger and I am still alive! It just tingled my tongue!

My point is the current would surely take the shortest route from the terminals on the plug so would only potentially hurt the localised area an not go anyway near the brain/heart?

My take on this is that maybe the charger was faulty and it was mains ground reference voltage at the plug end?

Anyone else have any theories?

Thanks

Cheap chargers are often NOT isolated from the mains, and in a place with 220V, they are very dangerous.

The designs focus on cost, not safety.

 

how is this test conducted?
Do they increase the voltage on the mains input side until the isolation has broken down?

My memory might no be right but:
We test the transformers to 3kv or 4kv depending on the product. Primary to secondary
We do not increase the mains voltage.
We short line and neutral together. Connect them to 1.5kv ac. Short the output + and - together and connect to return of the 1.5kv source. Measure the leakage current. We test for one minute.

 

Cheap chargers are often NOT isolated from the mains, and in a place with 220V, they are very dangerous.
The designs focus on cost, not safety.

Indeed. We had a teen girl get electrocuted a couple of years ago here in TX when her charging iPhone dropped into the tub where she was bathing. It was a chinese cheapie not isolated from the mains. No GFCI either. So many things wrong in the story including a lack of training about basic electrical safety but the gas-station charger was a big factor.

 

In demonstrating adequate isolation between primary and secondary circuits the Live & Neutral are commoned as are the low voltage dc outputs. A voltage of 3kVac is then applied between the two (across the reinforced) insulation, to pass no breakdown should occur.

For the purposes of type test, this voltage is applied for 1 minute. In manufacture this test should be applied to 100% of production, but only for a short period (2 seconds) to avoid stressing the insulation.

You might think a voltage of 3kVac to be on the excessive side, given that normally there is less than 250V across the insulation – but mains bourn transients of up to 2.5kV are present on a nominal 240V mains supply (within the appliance).

 

In manufacture this test should be applied to 100% of production

Agree...... The test is beyond looking for a high current short. It looks for low current leaking.

As to post #3 where 8/9 chargers fail isolation tests. I just tested a wide variety of small chargers and power supplies and I did not see any problems. I am willing to shows photos.

 

The samples selected for the surveillance activity were purchased by someone with an eye for suspect electrical products. They were not well known branded chargers or from reputable retailers; but were purchased from small independent shops selling electronic goods (mobile phones, powerbanks, travel adapters and such like).

To look at the chargers, there was nothing visual (to me) that would indicate a problem. After failing the electric strength test, the chargers were opened in order to investigate further. All the failed units either had substandard separation distances between primary and secondary circuits, and/or non-safety rated Y capacitors bridging the reinforced insulation (primary to secondary).

In one failed sample, it was observed that the primary and secondary circuits were only separated by the enamel on the transformer winding wires.