Plug-in Chargers

Plug-in Chargers

The total annual online sales of mains plug-in chargers are estimated to be in the region of 1.8 million. It is likely that most of these sales involve cheap, unbranded chargers.

In 2009, Buckinghamshire Trading Standards seized more than 3600 unsafe chargers from retailers over a 6-8 week period. 

Unsafe charger units are being manufactured in China from as little as $0.46 (Hong Kong Dollar), which is equivalent to 3 pence. Allegations have been made that Chinese manufacturers are submitting well-engineered electrical products for conformity testing purposes, but then removing non-essential components in production to reduce costs. 

The importation, wholesale and retail distribution network seems to be well established, spreading these chargers far and wide throughout the UK. But potentially they are not being subjected to the legal due diligence processes that underpin the free-flow of goods in the European Union, and indeed the global market, due to the lack of control over purchases made over the internet. 

During investigations by Trading Standards, traders claimed that they simply relied upon the veracity of the CE mark and made no subsequent checks of their own to ensure that the chargers were safe. The concept of personal responsibility and liability for the goods they sold was frequently alien to them. 

Electrical Safety First is concerned that many thousands of lives in the UK, particularly young lives, are being put at risk whenever cheap unsafe chargers are used to charge music devices, hand-held games consoles and similar electronic goods. 

The size of the problem

As part of our investigations, we commissioned an independent laboratory to carry out safety and performance testing on a selection of chargers purchased as new from well known online trading and auction sites, such as Ebay. 

For all ten chargers selected for testing, the departures observed from the relevant UK products standards were such that none of the samples met the principle safety requirements of the Electrical Equipment (Safety) Regulations 1994. 

One charger failed to operate on receipt. The tests on the others major concerns.

One charger presented a serious and immediate shock risk in that it was possible to detach the plug section from the adaptor by hand, leaving live contacts exposed to touch when inserted into a socket-outlet. 

None of the chargers had the required separation between live parts. Typically, there was insufficient insulation and distances between live parts and between input/output circuits. A fault could cause the output of the charger to reach mains voltage, leading to a risk of fire and electric shock. In one case, illustrated below, only a fine enamel coating between the primary and secondary transformer windings prevented direct connection between the mains supply and the charger output.

Seven chargers also failed a standard dielectric strength test, the insulation between the input and output circuits breaking down at an applied voltage less than the minimum required.

Under short-circuit testing, three chargers showed signs of significant internal component damage, with soot and metallic deposits covering insulated surfaces within the housing, as shown below. Internal short-circuit protection had failed to operate (or to operate safely) to prevent internal component and thermal damage. Failure of short-circuit protection is a significant fire (and potentially explosion) risk, as circuits are effectively fried.

In five chargers, the internal wires connecting the plug pins to the circuit boards were attached by solder only. Should a wire break free, its movement could cause a short-circuit, resulting in a fire hazard or mains voltage appearing at the charger output.

During testing, the cover of one charger had broken completely way from the base, presenting an immediate shock risk from exposed live parts. Also, the plastic earth pins of two chargers broke away from the base; one with only light finger pressure. If an earth pin breaks away whilst inserted in a socket-outlet, the safety shutters will not close to protect against contact with live socket contacts when the charger is withdrawn.

Five chargers had been wired using sub-standard components connecting the live parts of the primary and secondary circuits. The components used did not provide sufficient insulation between the mains supply and the output of the charger.

Live plug pins are required to be not less than 9.5 mm away from the edge of the charger. Nine chargers failed to meet this requirement; the worst case noted as having live pins only a fraction of a millimeter away from the edge. The main danger from the peripheral distance being less than 9.5mm is one of electric shock, although this is less likely (but still possible) where adequate insulated sleeving has been applied to the pins.

Incorrect plug pin alignment and oversized/undersized pins. If pins do not fit properly into UK sockets, overheating, arcing and damage to the socket can occur. Only one charger met the dimension and size requirements for plug pins. Three chargers could not be inserted into a standard socket gauge properly due to the incorrect alignment of plug pins.

Also, many of the chargers as delivered did not match the descriptions or illustrations given by the trader. In one case, a charger illustrated for use in the UK was supplied with plug pins configured for use in the United States only.

Apart from supplying an incompatible charger, it was also noted that the plug pins were bent, presumably during transit, due to insufficient protective packaging. 

It is evident from our investigations and the issues described above that there are many pitfalls and potential safety risks that may result from purchasing cheap unbranded chargers on the internet. 

As with all product safety investigations undertaken, we are following up all the identified failures with the retailers and manufacturers concerned, and keeping the relevant authorities informed of our actions.