Every so often we see on line storeys of fake chargers burning down houses, and electric shocks. Normally these chargers are refereed to as ‘Apple’ or ‘iPhone’ chargers, however that is just because the small triangle chargers (in a variety of colours) are so prevalent. An official Apple 5W USB Power Adapter (link).
A while ago (pre Britex referendum) I bought a 89p phone charger (with free shipping) from Ali express (link to a 96p one), just to see how ‘good’ it is, lets just say that you wont be surprised by any of this:
Having a quick go at checking to see how well it conforms to BS EN 55032:2015 – “Electromagnetic compatibility of multimedia equipment. Emission Requirements” (until the beginning of this month I would have considered BS EN 55022 [pdf]), It will have to comply to the Class B (Residential / Domestic) limit lines for conducted and radiated emissions
Conducted Emissions testing give us these results:
Radiated Emissions testing give us these results:
Looking at these two graphs, you can see that while the radiated emissions are fine, it fails to meet the requirements of the conducted emissions (Blue squares below the red line, green circles below the blue line). now we know its not permissible to place the charger on the market in the EU (including the UK) from an emissions point of view. We can now assess its electrical safety.
So lets look at what happens when we perform a quick LVD screen test
The results for the LVD screen test:
- Offload DC out 5.3 V
- DC maximum output before supply folded ~1 A
- Power used – 3 W off load, 8 W @ 1 A
- Earth Pin is ok, however spacing issues with Live and Neutral
- Fails a breakdown test 600 Vac @ 1 mA (does not recover).
- No secondary securing of internal primary wire to pins, or PCB.
- Single insulation mains in contact with LV / Secondary side.
- No physical barrier between Pins and PCB
- Capacitor between Primary and Secondary circuits is not Y rated.
- Separation between Primary and Secondary does not meet requirements.
- No mains fuse fitted
- Solder on rear of pins in physical contact with capacitor on secondary side.
- No Class II symbol on regulatory markings
I am sure it is safe to say that I was not surprised by the lack of conformity of the charger, I was however surprised at just how terrible it was!
I have had a number of iPhones over the years, and as such I have two real iPhone Chargers laying around, have a look at the markings on these two: