USB wall sockets?

tony6403

Smiley_Dan wrote: »

Generally these do draw power, albeit a small amount. http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12988

I have never thought about this before , but how can a USB point with nothing plugged in use any power by itself ; it is just an open circuit.

[Deleted User]

tony6403 wrote: »

I have never thought about this before , but how can a USB point with nothing plugged in use any power by itself ; it is just an open circuit.

Transformer losses.

prowla

CHRISSYG wrote: »

Why would you expect someone who works in retail to have electrical knowledge ??

I work in a similar place and people regularly ask questions that should be directed at a qualified tradesman, I can answer any questions where the information is one the product information but no more.

I would expect the store to have the information available about their products, which the staff would be able to refer to.

zax47

Bedsit_Bob wrote: »

Transformer losses.

But in an unloaded SMPS these are infinitessimally small.

"Copper" losses {Isq.R losses}occur only when current flows, and an unloaded SMPS will have only uA of current flowing....

Loss (in Watts) = I{current}sqd x R{resistance} x t {time of flow} , so when I is tiny, so is the loss - depending on the coil resistance it's still going to be mW.

"Core" losses are even smaller due to such tiny currents flowing.

Non of these are going to set your meter spinning........

zax47

prowla wrote: »

I would expect the store to have the information available about their products, which the staff would be able to refer to.

Me thinks you perhaps expect too much...

#whatplanetdoyouliveon

Smiley_Dan

zax47 wrote: »

...
Non of these are going to set your meter spinning........

Nobody said they would.

patman99

If you want a bit of extra protection, go for the double-pole ones. This means both live and nuetral are switched on/off with the socket switch rather than just the live connection.

Cornucopia

The concern is not energy wastage.

The concern is that electronics of possibly dubious build quality are permanently connected to the mains supply.

This is mentioned in post #21 at the top of this page.

jatinmistry_uk

I am having full house re-wiring done and the electrician has proposed to fit this. I think we will need 6 of this altogether in the house. I have two main concern which are safety and running cost. Could someone please advise:

1. If I say this is 2.1 amp, am I correct in saying that each socket will use 183.96 kwh per year as will be on constantly due to connected. (2.1 amp X 240 volt / 1000 = 0.504 kWh per day X 365 = 183.96 kWh)
   
   If this is the case and if you take unit rate of 0.12p the cost to have each would be £22.08 (183.96 X 0.12). This looks a lot especially my electrician has proposed 6 in total.
2. I am trying to read about this in few forum and have not found any conclusive information in terms of safety. As this is going to be connected and on all the time, is it safe as we might not be at home all the time?

The electrician has advised the Screwfix sockets which is currently on offer of 2 for £18. Any advise is greatly appreciated.


Thank you in advance.

zax47

jatinmistry_uk wrote: »

I am having full house re-wiring done and the electrician has proposed to fit this. I think we will need 6 of this altogether in the house. I have two main concern which are safety and running cost. Could someone please advise:

If I say this is 2.1 amp, am I correct in saying that each socket will use 183.96 kwh per year as will be on constantly due to connected. (2.1 amp X 240 volt / 1000 = 0.504 kWh per day X 365 = 183.96 kWh)

How do you figure that - they won't be consuming 2.1A 24/7, only when they have a device connected to charge (and even then only if that device requests/requires the whole 2.1A) When no device is connected then the current draw in "standby" (for want of a better term) is pretty tiny - in the order of mA at worst.

I am trying to read about this in few forum and have not found any conclusive information in terms of safety. As this is going to be connected and on all the time, is it safe as we might not be at home all the time?

No less safe than anything else you might leave on standby, and (in my opinion) much safer than most of the dodgy cheap Chinese chargers out there.

The electrician has advised the Screwfix sockets which is currently on offer of 2 for £18. Any advise is greatly appreciated.

Fitted lots now for customers - the BG (British General) brand ones from Screwfix will fit a standard 25mm deep back box, whereas many others I've tried, don't.