Martindale psi4000 non contact phase sequence indicator martindale marpsi4000 p the martindale psi4000 is a unique phase rotation indicator that carries out the measurement via inductive crocodile clips this method increases the safety of the user whilst the bright leds give a clear indication of either clockwise or anti clockwise phase rotation p p the design of this phase rotation tester allows for use on either insulated or uninsulated conductors and an enhanced brightness switch