USB charger socket

[David J Williams]

Hi, not looking for advice but wanted to share a problem which was driving me around the bend. Soon after we moved into our latest house which is an old former Welsh pub we decided to change one of the double gang plug sockets for one with the USB plug points built in. The socket change over went fine and all worked fine. Some months later the mains tripped on the Left hand side of the kitchen. My first thought was the fridge freezer was causing the problem so I used an extension lead and plugged it in on the other side of the kitchen. This seemed to sort the problem out. I left the freezer plugged in and nothing happened. I swapped the wires over in the consumer unit to check if the breaker was the problem but this was not the fault. I bought an insulation tester but all the wiring was OK. I set everything back again and plugged everything back in with the freezer plugged in on the LHS of the kitchen again. Months later the mains tripped again. After a few attempts the circuit breaker reset. I had looked up problems with the USB mains sockets causing earth leakage but could find no evidence of problems with them. Anyway the circuit breaker tripped again shortly after and as a last shot at sorting things out I swapped the USB socket back to a standard one. There has been no more issues with tripping and I can only assume that the USB socket was the culprit. The house has the 2 foot thick rubble walls but I couldn't find any signs of damp in the wall. I spent far too much time on this and even contacted the previous owner to check if they had any issues with the kitchen electrics but they said that they hadn't. I don't think I will be using these sockets again even though they appear a good idea. The socket manufacturer is Axiom

 

[EFLImpudence]

Try the seemingly faulty socket on another circuit.


I am assuming it is an RCD tripping but you don't actually say.

 

[ericmark]

I also had an RCBO trip, which also did most of the kitchen, and also two bedrooms above and a dinning room. So it was the normal thing of unplugging all I could until I could reset it, and on disconnecting the dishwasher finally I was able to reset.

I was about to buy a new dishwasher, but thought I would test it first, and many MΩ at 250 volts on all tests, so plugged in again, and not tripped since.

I did wonder about some capacitive or inductive linking, but all circuits together were only 8 mA.

I would put the socket in a surface mount box, with a short lead and a plug, and see if it still trips. I had some smart sockets I was not happy about, and I did that, so easy to remove from service.

Today all smart socket adaptors and USB adaptors, but still have some left with USB or Smart sockets.

But you simply don't know if the socket was at fault, and it seems unlikely any part of the circuit to get 5 volts DC is linked to earth.

 

[SUNRAY]

Try the seemingly faulty socket on another circuit.

This may prove it to be faulty but bear in mind the cumulative EL may be very different on the other circuit

I am assuming it is an RCD tripping but you don't actually say.

 

[David J Williams]

Hi
The Rcd was tripping and wouldn't reset until the kitchen LHS breaker was set to off. I have thought about putting the socket on another circuit in the house but have lost faith in them. The socket with a mains plug is a good idea.

 

[SUNRAY]

Hi
The Rcd was tripping and wouldn't reset until the kitchen LHS breaker was set to off. I have thought about putting the socket on another circuit in the house but have lost faith in them. The socket with a mains plug is a good idea.

I have several of them around the house and additionally have a couple in a portable unit. So far not had any issues with them, I'll make a guess they are all BG.
However I've known of some being troublesome.

 

[Taylortwocities]

I bought an insulation tester but all the wiring was OK.

Be careful when zapping USB sockets with an insulation resistance tester. USB sockets may not like 500volts being put up their jacksie!

 

[David J Williams]

I removed the socket and swapped in the original to avoid damaging the USB circuitry