voltage tester / for cables / portable / non-contact
The HHM-NVC40 provides a safe, non-contact way to check if an electrical cable, plug or socket is live. It does so by sensing from a short distance the electromagnetic field created by AC voltage. Even unloaded AC circuits generate electromagnetic fields. Although these fields are extremely weak, their constantly changing nature means that they generate some current.
A sensitive non-contact voltage detector can sense this current via induction, in much the same way that a sensitive radio receiver can sense weak radio waves. Non-contact voltage (NCV) detectors, including the HHM-NCV40, cannot detect DC voltages (such as those found in automotive electrical systems) or AC voltage through a wall or metal conduit.
Unlike the typical NCV detector, the HHM-NCV40 has adjustable sensitivity—a feature that makes it possible to determine which wire in a bundle is the live wire. This application calls for turning down the sensitivity in stages after the HHM-NCV40 senses voltage. As you reduce sensitivity, at some stage only the live wire will produce a field strong enough to activate the audible and visual alarms from a short distance. In this way, the HHM-NCV40’s adjustable sensitivity takes the guesswork out of identifying the live wire of a bundle.
The HHM-NCV40 also has a wider detection range (5 to 1000 Vac) than a typical NCV tester.