Dave Plowman wrote:
In article ,
dave L wrote:
I'm a little intrigued that the two cheaper tools are showing the the
phase terminal is live when there should be no current. My real
concern is that these tools infer there is current flowing to the
terminal with the pendant is swicthed off and that there's a
possibility of getting electrocuted when changing a bulb.

What you're seeing is inductive coupling between the 'live' wire and the

Capacitive more likely.

switched one running next to it. Put the bulb back in and you'll see zero,
as the switched line will be connected to neutral via the much lower
impedance of the bulb.

Things like neon screwdrivers - and DVMs - have a very high input
impedance so will read very low currents that the body wouldn't feel.

It's a good idea to use a low value shunt which draws about 0.1 amp when
using a high impedance test device on mains - or alternately make up a
test lamp using a small mains bulb.

This is one of the reasons that I use my 'cheap' analogue meter when
checking for mains, it's much more likely to give me a useful reading
than a digital meter and is also easier to quickly glance at and
check.

--
Chris Green )