What type of coating can a low voltage holiday detector be used on up to?

A low voltage holiday detector is typically used for detecting defects in non-conductive coatings, such as paint or coatings applied to metal surfaces. The correct response indicates that a low voltage holiday detector can effectively be used on coatings up to 20 mils thick.

This thickness range is significant because low voltage holiday detectors apply a low voltage pulse to determine the presence of holidays (or discontinuities) in a coating. If the coating thickness exceeds approximately 20 mils, the sensitivity of the detector can be compromised, making it less effective and possibly allowing undetected holidays.

These detectors are not suitable for thicker coatings due to the electrical characteristics and operational principles involved, which rely on a lower voltage to effectively identify flaws in a more controlled environment. Coatings exceeding this thickness often require different methods or higher voltage detectors that are specifically designed for thicker coatings.