Elcometer 236 High Voltage Holiday Detectior

The High Voltage Detection Technique locates flaws in insulating coatings on conductive substrates. A power supply within the instrument generates a high DC Voltage which is supplied to a suitable probe. An earth voltage return lead from the instrument is connected to an uncoated area of the metal of the test substrate.

As the probe is passed over the coated surface, a flaw is indicated by a spark at the contact point with an audible alarm in the detector and a visual alarm in the probe handle.

Note: This test uses the principle of an electric current conducting through a material. When a spark occurs, the circuit is closed and the alarm sounds indicating a flaw. Varying the DC Voltage varies the distance a spark will "jump" to the metal substrate. The maximum distance a spark will jump is dependant on the dialectric strength of free air.

The High Voltage Technique can be used to locate flaws in coatings on concrete. As most concrete conducts electricity (due to moisure inherent in concrete), the Elcometer 236 can be used.

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