Testo 0590 7450 745 non contact voltage tester testo 0590 7450 p the testo 745 non contact voltage ncv tester quickly checks for the presence of voltage in ac powered systems it can be safely used up to 1000v ac p p when ac voltage is detected the testo 745 gives indication by flashing red leds and sounding a buzzer you can easily determine the live and neutral pins of an outlet without lengthy and risky removal of the outlet the testo 745 ncv has a built in low pass filter which gr