Few questions about shaver sockets

[dimmer]

Struggling to understand the safety aspect.

I understand that the transformer separates the supply voltage from the secondary and removes the earth (tied to neutral?)

But can I be a new earth for the current to want to flow too?

What would happen if I dropped my shaver in a sink full of water, could I get a shock if I picked it out?

Why keep the secondary voltage at 230v why not bring it down to 12 volts,

The earth is isolated but shaver sockets have an earth fixing point which appears to be attached to the transformer body, could that not compromise the separation

Thanks

 

[OwainDIYer]

Struggling to understand the safety aspect.

I understand that the transformer separates the supply voltage from the secondary and removes the earth (tied to neutral?)

But can I be a new earth for the current to want to flow too?

Current will only flow through you to earth if the supply end is also earthed. As the transformer output is isolated from earth, there can be no current flow to earth.

What would happen if I dropped my shaver in a sink full of water, could I get a shock if I picked it out?

The only way you could get a shock would be if part of you was touching one of the shaver wires and another part of you touching the other shaver wire. (I won't refer to them as L and N). With a fault on the shaver exposing one live part there would not be a shock risk. With two faults on the shaver exposing two live parts there would be a shock risk but because the two contact points would be close together the shock would most likely be finger-to-finger and would not pass through the torso.

Why keep the secondary voltage at 230v why not bring it down to 12 volts,

So you can plug shavers into ordinary mains sockets with an adapter, outside the bathroom.

The earth is isolated but shaver sockets have an earth fixing point which appears to be attached to the transformer body, could that not compromise the separation

No because that's earthed back to the supply earth so if it broke down the circuit protection would operate in the ordinary way. The only exposed live part would be the fixing screw and you'd be unlikely to be touching that. Under <16th Edition that would be equipotentially bonded to other bathroom metalwork too, under 17th Edition it would be RCD'd.

 

[dimmer]

Many thanks for the reply.
Im afraid I still don't really get it.

If I am at zero potential and the secondary live is at 230 there is a potential difference.

There is 230v potential difference between live and neutral on the secondary
how is that achieved. when the earth reference has been removed?

 

[ban-all-sheds]

Many thanks for the reply.
Im afraid I still don't really get it.

The key word is the 2nd one in "potential difference".

If I am at zero potential

At zero potential (difference) with respect to what?

and the secondary live is at 230

At 230V with respect to what?

there is a potential difference.

Between the two ends of the transformer secondary, not between either of them and anything else in the entire universe.

There is 230v potential difference between live and neutral on the secondary
how is that achieved. when the earth reference has been removed?

Consider a battery.

Where's the "earth reference"?

But there is a voltage between the two ends of it.

If you put one probe of a voltmeter on one terminal of a battery, and the other on something earthed, would you expect to register a voltage? If you put your tongue on one terminal of a PP3 battery would you expect to feel anything?

 

[Electrifying]

So, Dimmer, your next question should be 'Why don't we supply the whole house like the shaver socket then, and eliminate the 'shock risk'........i.e. no reference to earth, no path to earth, no shock risk.