Bathroom shaver/toothbrush socket - what does it consume when unused?

[readiescards]

I'm very reluctant to have anything running 24*7 but partner already moaning about having to charge her toothbrush outside of the bathroom in the holiday cottage we are currently renting while the new place is built.

 

Question: does a shaver/toothbrush socket when not in use consume power?  

 

 

 

 

[Guest Alphonsox]

Interesting question - Almost certainly yes, I would guess a few watts. I have a unit about to be installed. I'll try and measure it tomorrow.

[ProDave]

I always thought there was a switch, activated by putting a plug in, that energised the transformer.  Certainly all the ones we have are like that, so nothing plugged in = no power.

 

That doesn't help though as one or other toothbrush is always on charge.

 

To check, with nothing plugged in, put your ear to the socket and I will bet you cannot hear the hum of the transformer.
 

[Guest Alphonsox]

So inserting a plug across the secondary activates a mechanical switch on the 240V primary of the isolation transformer ? Makes sense but you have got to hope that they've thought through all the possible failure modes. Never liked shaver sockets to be honest, a beard has always seemed the safer option.

[AliG]

I found an MK spec sheet. They give standby consumption of 0.15W for a USB socket, but they don't give standby consumption for a shaver socket which is an isolation transformer. Shaver sockets are rated for 20VA, so 20W although they also seem to be rated as 200mA, 230V which would be 46W as their trip level I cannot find anything other than a guess at their power consumption. It doesn't seem that they are covered by the regulations that have reduced mobile phone charger consumption to negligible levels.

 

I cannot find any mention of a switch in the spec for these, it may be there, but I cannot find it mentioned. Some specs say that they have an interlock so you cannot plug something into the 110V and 230V at the same time. I always thought this was the click they made. Although I found some people claiming to have sockets they can put two devices in at once. Thinking about it, if there was a switch before the isolating transformer wouldn't this increase the risk of a shock at the full supply power  and seem to be unlikely from a safety point of view.

 

They might use 0.5-1W which would be 4-8kWh a year. Maybe 50p-£1.

 

Oral B suggested that a toothbrush on charge all year used 2.8 kWh, so that is about 35p a year in electricity.

 

A Sonicare Elite uses 3W, although it isn't clear if it reduces consumption when fully charged. Anyway 3W continuously for a year is 26 kWh, so £3. This improbably a worst case scenario.

Edited October 18, 2016 by AliG

[ProDave]

All insignificant compared to the cost of the toothpaste.
 

[Barney12]

9 hours ago, ProDave said:

 

To check, with nothing plugged in, put your ear to the socket and I will bet you cannot hear the hum of the transformer.
 

 

Imdeed! Even more so than a trip to the dentist [shudder]

 

just fit and forget, you'll have much bigger things to worry about. 

[Ferdinand]

11 hours ago, Alphonsox said:

So inserting a plug across the secondary activates a mechanical switch on the 240V primary of the isolation transformer ? Makes sense but you have got to hope that they've thought through all the possible failure modes. Never liked shaver sockets to be honest, a beard has always seemed the safer option.

 

Fire or Beard of the Year award risk excepted, I guess.

 

[Onoff]

Long winded discussion about magnetizing currents, impedance, unloaded trannies and the negligible consumption therein or.....

 

 

Case closed!

 

Erm......case reopened......just realised she wants to charge in the bathroom. So.....just put the socket 3m away from the bath / shower. 

Edited October 19, 2016 by Onoff

[readiescards]

So minimal but not zero. Still not keen. Mighty have to look for a clockwork toothbrush

[Guest Alphonsox]

I didn't manage to do any measurements today, but did dismantle a Screwfix LAP Shaver socket. I can confirm that this model doesn't have a switch in the supply.  The incoming mains  is passed through what I guess is a thermal fuse before being directly connected to the isolation transformer primary.

[readiescards]

Ta for the initial part of the investigation @Alphonsox