Dielectric withstand voltage testing is useful for design verification, quality control of materials, and workmanship.

This test method is used to verify that the membrane switch can operate safely at its rated voltage, and withstand momentary overpotentials due to switching, surges and other similar electrical phenomena.

Specific areas of testing are, but not limited to:

Conductor/dielectric/conductor crossing point,

Close proximity of conductors, and

Any other conductive surface such as shielding or metal backing panel.

Dielectric withstand voltage testing may be destructive and units that have been tested should be considered unreliable for future use.

Testing using ac voltage may be useful for switches intended for control circuits powered by ac voltages.