This test determines powder volume resistivity by the simultaneous measurement of voltage and current passing through a test sample of known cross sectional area and depth.

The test method is described in BS 7506 part 2. A cylindrical test apparatus is used with a lower electrode and insulation body. A measured volume of powder is placed in the apparatus and a tight fitting upper electrode is inserted on top to compact the powder and provide a means of applying voltage to the sample. DC voltage in the range 1000 V to 5000 V is applied across the dust sample and current flow is measured by a suitable ammeter. The test is repeated three times and the average measured current and applied voltage determined. The powder volume resistivity is calculated by multiplying the applied voltage by the cross sectional area and dividing by the product of the measured current and the sample thickness.

Samples are conditioned for 24 hours before the test at 50% relative humidity.