Aliexpress power supply comes with IEC Cable with no earth, issue?


I recently ordered some power supplies on Aliexpress with IEC connectors/cables instead of screw terminals to rather not setup local insurances and stuff like that.
However, I noticed that the cables that were delivered with the supplies feature only two contacts, so no earth, on the socket side but where it connects to the power supply they feature three contacts, as the power supplies do.
So clearly the cables are faking the earth contact. However, the power supplies feature an earth contact.

Would you find that an issue?

Post links to the products.
Double-isolated appliances (supplies) don't need an earth connections.

Do you have a DMM? With the line power disconnected, see if there is any continuity between the IEC ground post on the supply, and the output ground (if there is one... a link would have been useful).

Or just blindly replace the cable with a 3 prong plug cable.

Thanks for your responses.

I know of double isolated devices but... why is there a third contact for earth? Just for compability?

I measured between GND output and earth. There is no direct path, Resistance is over 22 MOhms and on the 24V one there is abaut 2-4 nF capacitance while on the 5V is rarely any capacitance.

The product link is this: AC DC Netzteil 12V 5V 6V 8V 9V 10V 12V 13V 14V 15V 24V 1A 2A 3A 5A 6A 8A Transformator 220V ZU 12V AC Power adapter Led treiber|Switching Power Supply| - AliExpress

I also attached some original pictures of the power supplies I received.

The problem with buying such items is it’s a judgement call - you are buying cheap items which may or may not have been designed to any relevant standards , you pays your money ....
CE marks etc may not really mean anything .

Having said that it may well be fine and probably is - I would expect isolation between the out going 0v and the earth pin and the casing is plastic and may well comply with double earthing - don’t know
. But is there isolation between the output and the power input may be another matter and depends on the internal design , which is likely to be a switched mode design ?

I have bought cheap CE marked Low voltage Christmas tree lights for outdoor use and found the supply live on the bulbs.

I guess you could earth down on the output if YOU feel that is a solution - it’s not really fair to ask for advice on a devices design , unseen, on a hobby forum, from people who may or may not be qualified ( same as asking a passer by in the street for his opinion) - people here should not take on that responsibility.

The two concentric squares symbol tells you that the device is double insulated and so no earth is required.

...with IEC connectors/cables...

Which ones.
There are many (scroll down).

Post links to the products.
Double-isolated appliances (supplies) don't need an earth connections.

Anything from AliExpress needs PAT testing and a reliable PE...

This business of buying stuff from “greater Wuhan” in general, is a worry.

I just had a root through my tubs today, looking for the DVI <==> HDMI lead. I found them! :grinning:

I found however, a bag of (?50) of the coaxial power line sockets that fit (for example) the “barrel connector” of the Arduino Duemilanove/ UNO etc. I noticed many of the latticed strain reliefs had broken off. By squeezing the bag, I can easily crush the whole of the cover of all the connectors, just like popping bubble wrap!

I might as well just for fun. After all, they are - at least the covers - completely useless in this condition. If it is non-critical (or even if it is?) I can just bodge up the connectors with heatshrink as a cover, perhaps two layers and that will be as good as the original covers, it’s just the appearance of it (and the extra trouble).

And another bag of a smaller quantity is just fine, the plastic is flexible. It was obviously a dud batch. Is that why they sold them “cheap”? They were apparently intact when I purchased them a few years ago but they have completely failed and thus were absolutely not “fit for purpose”.

This did lead to some household discussion about the consequences of our total dependence on that country even aside from that business about the 5G company.


Chinese Export :confused: