Electricians know that when you are measuring electrical installations there often appears to be a voltage, even if you know the wires are non energized. This is called stray or ghost voltages and is caused by the capacity between wires. Because of the very high impedance input of the meter, this stray voltage has nowhere to go which will lead to an incorrect reading on the meter. The solution is to make sure there is a lower impedance across the input terminals of the meter. However, this is not as easy as it seems since it is vital that the safety of the electrician is not compromised.