What is the suggested length from the fixture to a test jig, type of cable and type of connector if anything specific is required?
The length of the Kelvin wire connection from the fixture to the test jig (DUT) is largely dependent on the test frequency. The impedance effects of this connection are mostly cancelled by open circuit and closed circuit compensation performed when running a program. Compensation measures the characteristics of the fixture to test jig Kelvin lead connection with a closed and open circuit and subtracts this from the measured quantity thereby theoretically cancelling the unwanted effects of this wire connection.
At low frequency the wire length is far less important than at high frequency. At high frequency (around 100KHz to 3MHz) it becomes increasingly difficult to achieve accurate compensation and stray impedance effects of this Kelvin wire connection may adversely affect measured results with long lengths. At low frequency, especially 100's of Hz the Kelvin wire connection becomes less dominant and longer lengths can be tolerated. I have seen test configurations with over 6 feet of fixture to test jig Kelvin cable connections with acceptable results. To state the obvious the shorter this connection length is, the better.