Leo,
I think you are correct & agree the statement is confusing.
Ultimately you don't need to trust your life to web sourced advice.
I suggest you power your device via a "leakage current detecting breaker".
Alternatively, simulate the silly child manoeuvre & put your finger where it
should not be.
If you are in good health & are carefull not to make a circuit across your
chest you should be safe even if "stung"
Pete


"Leo Meyer" wrote in message
...
Hello!

I found a description of a series light bulb circuit on the net at
http://www.vintage-radio.com/project...-limiter.shtml
and there's a statement which confused me a bit:

"Note that the lamp is in the live side of the mains supply, not the
neutral.
This is for safety, so that the neutral side (and the chassis in AC/DC
sets)
stays close to earth potential no matter how much voltage is dropped
across
the lamp."

Now I built an isolation transformer into a box with a lamp socket
connected
to a bypass switch, i.e. if the switch is open both socket pins are
disconnected.

However, I put the lamp socket into the return wire, not the live wire,
because I want to use differently rated bulbs (quick exchange) and the
socket, if empty, is a great place for children or other innocent people
to
poke their fingers in. So, even if the switch is closed connecting the
lamp
in-circuit, accidentally touching the fixture should be safe.

For us in Germany it's possible to put a 230V plug into a live socket both
ways round, so we're not sure which wire is actually live. That's why I
use
an LED to indicate wrong polarity; it lights when my intended neutral is
live in respect to earth ground, so I can simply change plug orientation.

For this reason I don't understand the statement above. If I've got an
appliance which uses only two wires I'm pretty sure that no point of the
chassis is directly connected to either (because any of them might be on
live voltage). In fact, most of these contain a transformer or SMPS and
the
secondary side 0 potential is usually connected to the chassis.

And if I've got an additional earth ground this is the one usually
connected
to metallic parts. So according to my thinking I should be quite safe
putting the lamp into the return wire.

Am I making a mistake and should I better put the lamp into the live side?
Are there devices in other countries which use a fixed setup of
live/neutral?
Or am I simply already too tired to understand?

Any help is greatly appreciated (my life may depend on it ;-)

Regards, Leo