NECA Technical often receive calls from members who have measured voltages in the vicinity of 60 volts at a light fitting, with the light switch off. In most cases, these voltages result from the switch wires on the circuit forming a capacitive coupling.
The voltage that results from this capacitive coupling can be measured in the de-energised switch wire, with voltages between 60v and 120v being common. Most modern digital multi meters are a high impedance type, which are very sensitive and will pick up these voltages. This can cause confusion when fault finding. There are multi meters available with a low impedance setting (LoZ) that will not display these false voltages during use.
NECA WA highly recommends that this type of meter be used for any fault finding related work.