Electricians know that when measuring electrical installations, voltage often appears to be present on them, even when the wires are known not to be live.
This is called leakage or phantom voltage and is caused by capacitance between the wires.
Due to the very high impedance input of the meter, this leakage voltage has nowhere to go and this leads to an incorrect reading on the meter.
This can be solved by ensuring that the impedance across the inputs of the meter is lower.
However, this is not as easy as it seems, as it is vital to ensure the safety of the electrician.
Key features
The Fluke TL225 provides the solution by ensuring the meter has a low input impedance that eliminates leakage voltages
For live wires, the meter indicates the actual voltage
For circuits that are not energised, the meter indicates close to zero (even if there are leakage voltages)
It can be used with all modern meters that have standard spacing between inputs