lackisolierter

lackisolierter is a German term that literally translates to “paint‑insulated.” It refers to a condition in which a metallic component that is normally grounded or insulated is covered in paint or varnish that has become a conductive medium, thus compromising the intended electrical isolation. The phenomenon is typically observed in older electrical and electronic equipment where paint was applied for aesthetic or protective reasons but inadvertently formed a continuous path of conductivity between live parts.

The origin of lackisolierter is traced back to the early 20th century, particularly in electro‑mechanical devices such as motor generators and control panels. During that era, enamel coatings—typically shellac or phenolic resins—were used extensively. When these coatings delaminated or were not consistently applied, they could bridge contacts and create unintended paths for electric current. This led to design revisions and the introduction of dedicated insulating materials such as mica, glass‑filled polymers, and ceramic composites.

In contemporary engineering texts, lackisolierter is cited as a classic example of dielectric failure. It is included in safety manuals and IEC standards to illustrate the importance of maintaining proper insulation integrity. Engineers now routinely use Non‑Destructive Testing (NDT) techniques such as dielectric strength measurement and high‑voltage insulation testing to detect such conditions early during maintenance. The term also serves as a historical reminder of the evolution of insulation technology from simple paint coatings to sophisticated, norm‑compliant insulating systems.