Does anyone know how to troubleshoot these wall outlets? Both USB ports are dead however the wall outlet port works just fine. Prior to this I was able to successfully charge from USB port for about a week, and there has been no change in wiring. Is there a fuse ? Tendency to overheat?

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    "A look inside a (crap) double gang socket with USB outlets." - or why these things may not be a universal boon to all mankind and a joy forever. Sep 21, 2016 at 14:08
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    Legrand though is a major electrical supplier, you would hope their build quality and design would be up to scratch. I can understand one from china with unknown provenance failing. Any reason you can't take it back Quantum?
    – D-on
    Sep 21, 2016 at 23:03
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    As a general idea, USB ports for charging built right into the wall sound like a great idea. However, as USB standards change, you begin to find yourself with outdated ports that aren't usable for newer devices that either have a different shape connector (USB-C, anyone?) or that require more power (1A, 2.4A, 5A, 9A, do I hear 12A?). Stick with regular 3-prong grounded outlets and use the wall warts that come with the newer equipment that support the latest standards. That 3-prong outlet won't go out of style any time soon...
    – FreeMan
    Feb 24 at 17:08

2 Answers 2


Unfortunately these USB sockets fail regularly. We constantly seem to be replacing them. The irritating thing is that the failures aren't all from crap brands. Market leading brands like MK and Legrand fail just as much as the cheap China knock offs. I have never seen any of these sockets to be fused before, but clearly they are overloading. iPads and other tablets seem to be the largest culprit as they draw way more than standard current. However, it's a disappointment from the mainstream brands that they do not have a self resetting overload function or at a basic level a simple fuse. Crazy how smaller electronics companies can make robust chargers yet they can't.

As for diagnosing. There really isn't anything to diagnose unless you try a different cable and device to check for charging. Normally it will require replacement. I would ask though what are you charging in this device? And secondly do you have the socket part number as the socket will have a data sheet with its maximum rated current for the USB socket part.


Depending upon the manufacturer there may very well be a huge range of quality related to the reliability of the USB charger portion of the outlet unit.

Just think about that basket of multi-colored cheap plug-in USB chargers near the checkout at the retail store. Almost certain to be the lowest tier of quality.

So consider evaluating your unit relative price and reliability. Maybe the simplest thing is an upgrade or replacement.

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