In response to "But live must connect to neutral somewhere to complete the circuit."

Live--------Switch-----Lamp-------Neutral

In response to "that connection [between live & neutral] is made at the bulb and the switch opens / closes a gap in the live wire"
No, one is connected one side of the load and one to the other side.

Which makes me think that we are talking at cross purposes. After all here the bulb is the load.

If there were two live (correct sense) wires going to the switch, the lamp would not light,
As you have not explained what 'live (correct sense)' means, I am somewhat confused. There is a Live wire and a Switched Live wire at the switch and the lamp does light, so I take it one of those is not a 'live (correct sense)' wire. Presumably the Switched Live is not a 'live (correct sense)'. Is that right?

The fundamental flaw in your thinking is that the wires are determined by colour and are Live and Neutral before you connect them.
As I said earlier, I did not mention wire colour. I did not take the wire colour to mean anything.

The circuit is merely a conductor split by the supply, lamp and switch positions.
You could insert a switch in the Line or Neutral, but it must be placed in the line.

So the way that light switches are wired, the switch is physically in the Line half of the circuit (e.g. at 2 o'clock).
I was thinking that a switch physically in the Neutral half of the circuit (e.g. at 4 o'clock) would be connecting Line & Neutral.

What I think you are saying that by definition Line ends at one side of the load and Neutral starts at the other side of the load. Is that right?

Live--------Switch-----Lamp-------Neutral

In response to "that connection [between live & neutral] is made at the bulb and the switch opens / closes a gap in the live wire"

The current comes along the Live wire and gets to the Switch,
If the switch is OFF then the current goes no further.
If the switch is ON then the current goes further and travels along the Switched Live to the lamp.
The current tries to get through the lamp. This is because the current is wanting to get back to the power station and the best way is along the Neutral.

The lamp doesn't like current passing through it and it limits how much current can get from the Switched Live through the lamp to the Neutral.

If the current through the lamp is less than the fuse ( MCB ) rating then all is good.
The lamp prevents unlimited current flow from Switched Live to Neutral.
If someone connects Switched Live to Neutral without a lamp or other appliance to limit the current then unlimited current flows and fuses blow. Or wires over heat, melt and set fire to things.

To be blunt if you cannot understand that there is no direct connection between Live ( or switched Live ) in the lamp to Neutral then your understanding of basic electrics is inadequate for you to do any work on electrical equipment.

Perhaps this will help

Live--------Switch-----Lamp-------Neutral

The lamp doesn't like current passing through it and it limits how much current can get from the Switched Live through the lamp to the Neutral.

If that's the case, how come the RCD doesn't operate?

If that's the case, how come the RCD doesn't operate?

Because the same current flows in both Live and Neutral. There is nowhere else for it to go.

Because the same current flows in both Live and Neutral. There is nowhere else for it to go.

Yes, I know, Bernards explanation wasn't correct.

Yes, I know, Bernards explanation wasn't correct.
In what sense was it incorrect?

Bernard was talking about current travelling from 'Live', through switch and lamp to Neutral - such that the same current would flow through both live an neutral (so that an RCD would not trip).

Kind Regards, John

In what sense was it incorrect?

Bernard was talking about current travelling from 'Live', through switch and lamp to Neutral - such that the same current would flow through both live an neutral (so that an RCD would not trip).

Kind Regards, John

He said the lamp limits the current going from switched live to neutral? By which I read the current drawn at switched live is lower than the current at neutral.

The same as your kitchen tap limits the flow of water from the supply pipe to your kettle.

Perhaps this will help
Thanks for trying to help. I think the problem here is that all of the electricians are used to expressing things in a certain way (nothing wrong with that, all trades have conventions and use language in a specific way) and when I used words/phrases to mean something different there was confusion.

As I said, I was thinking that a switch physically in the neutral half of the circuit would be connecting live & neutral, like this

In that diagram I was referring to the wire labelled B as live, in that if you held on to it and were earthed you would get a shock, but it seems that electricians would not refer to it in that fashion.

As an example of people using words differently:
To be blunt if you cannot understand that there is no direct connection between Live ( or switched Live ) in the lamp to Neutral then your understanding of basic electrics is inadequate for you to do any work on electrical equipment.

Which (as well as being unnecessarily rude) seems to me to be nonsense. I would take a piece of wire to be a "direct connection", and in an incandescent bulb the electrical connection is just that, a piece of wire.

Presumably Bernard means something different by some of these words.

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You should never switch the neutral, always the live. If a normal dwelling has switched neutrals something is very wrong.

You should never switch the neutral, always the live. If a normal dwelling has switched neutrals something is very wrong.

Doesn't France use switched neutrals?

If a normal dwelling has switched neutrals something is very wrong.
I did not say I had that.

You should never switch the neutral, always the live.
I did ask if switches were arranged in this way for a good reason but did not get an answer.

and in an incandescent bulb the electrical connection is just that, a piece of wire.

So explain why the "piece of wire " in the incandescent bulb glows white hot yet the other pieces of wire do not even get warm.

as well as being unnecessarily rude

Advice that is given to try and prevent accidents can seem to be rude.

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