USB power socket

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Do some research.
I recall reading several articles about poor safety record of this style of socket - I maybe read them on this forum.
 
I've fitted two of a similar type from Screwfix . One has my pad permanently plugged in, I also charge my phone and radio ear defenders using them , no problems. So long as they are from a reputable source, i.e. a real CE mark not Chinese counterfeit they should be fine.
 
I fitted one of those from Toolstation about 4 months ago. Not had any problems and use it daily for charging my iPad and phone.


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I've had a couple of doubles in the kitchen for over a year now, from Screwfix, no problems so far.
 
Not sure I would. First, they are always on, the switch doesn't apply to the USB. So scope to be a firestarter. And there are some shockers out there. There's a guy on YouTube did an autopsy on one, which left one of the sockets not earthed if fitted in a plastic box, and had failed in such that the USB was connected to mains live.
 
phil.p":o9udtitn said:
Sheffield Tony":o9udtitn said:
Not sure I would. First, they are always on...

There are undoubtedly millions of unswitched sockets in daily use. :?

Yes, but the power source of the mains is (presumably) located miles away from your house, so the heat dissipation isn't your problem ;)

Having said that, I'm sure the USB sockets switch off (electronically at least) when not in use. I have fitted several in our house but I'm not convinced their as good as a proper charger. My old iPod in particular doesn't like them.
 
Yes, but the power source of the mains is (presumably) located miles away from your house, so the heat dissipation isn't your problem ...
I can't quite see the relevance of that - I'm struggling to see how a low amperage unswitched outlet is somehow dangerous and a higher amperage one safe?
 
What I mean is that the USB outlet contains a switching power supply, which is always connected to the mains in some if not all of these sockets. So it is like leaving a charger plugged in to an ordinary socket and switched on all the time. Ok that only draws the standby current of the charger when not in use which you would hope is small, but any fault in the charger circuit's electronics has potential for an exciting outcome. And the cheap ones have dreadful electronics. So best avoided altogether, but if you must use them, use a good brand like MK. Don't use generic cheapies under any circumstance.

I also suspect this could turn out to be a decision like wiring up your whole house with CAT5 20 years ago - seemed an excellent idea at the time, but technology changes. At least easier to revert to standard sockets than ripping out all that unneeded network cable !
 
In years past, if you wanted a 5V supply, to do it nicely you'd need seven components:

1. A transformer, ratio 240:3.6 approx, giving you 3.6V AC from the mains
2. Four diodes in bridge rectifier configuration, giving you full-wave rectified DC
3. A reservoir capacitor - pick a value - that smooths the FWR DC to a steady 5V.
4. An output fuse, to protect the charger (of no value to the thing being charged!). I'm assuming there would be one in the mains circuit, too - either a fused plug or a miniature circuit breaker.

You might complicate matters by adding a regulator, to ensure mains fluctuations didn't affect it and the circuit would need a slightly different transformer and a few extra things. The current available for charging would depend on the transformer. Sensibly, as the output would be floating, you'd tie one side to earth, so a fault would trip the RCD, too, and/or blow the fuse faster.

But the expensive bit of that is the copper in the transformer. Enter switched-mode power supplies. which I'm not going to explain here, except to say the idea allows for a much smaller transformer, is more efficient, but also potentially quite a lot more dangerous - to get to your 5V, high voltages and frequencies are usually involved.

Your "traditional" design doesn't emit any radio frequencies at all really, but a switched-mode supply has an oscillator, usually operating from around 20kHz upwards, so it is quite capable of being a radio. Furthermore the "switched" in the name creates nasty waveforms inside it, which also add to the radio-frequency interference it chucks out. They need suppression, and expensive testing of the designs to ensure they don't emit. This is often skimped. Then they "buzz", all over your radio reception, your WiFi, Bluetooth and so on, and even directly into your HiFi if the emissions are strong enough and the HiFi has issues.

It's a more complex circuit, they are often miniaturized but not necessarily reliably, they do consume power when not charging anything, if they fail you have to replace the entire socket, and, as has already been said, the circuit is in proximity to mains.

We have quite a few switched-mode units in the house which are either not earthed at all or inadequately earthed, including Laptop PSUs from leading brands. They are bigger, and supposed to pass stringent testing too, and they cost a lot more than these USB socket plates do. It's not unusual to get a belt from one.

So, of the socket plate, guess what proportion of its manufacturing cost goes on the USB charger. Given the retailer will probably be operating at 60% markup, and the OEM manufacturer probably makes 15-20% of their ex-factory price as profit, you can see this is the ultimate building down to a price for this sort of thing.

In summary, for me no bargepole could be long enough.
 
big clive took one apart a while ago. it was dirt cheap and not very good and it was dangerous.

decent one from the likes of screwfix are a bit different.

I don't want one, but that's by choice.
 
I don't know enough to comment on safety, but when I looked at them for my place, my son pointed out that the modern phones have 'smart / fast chargers' - which do work better and more efficiently than USB into standard sockets/adapters.

Just a thought.
 
For the record;

I have now crossed this item off my tool station shopping list.
Thanks for the advice.
 
As posted earlier, if it's got MK on it it's going to be okay.
The "tesco tearaways" are best avoided :D
 
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