Dielectric Strength

Q. We are considering using e-coat to paint electrical cabinets and wanted to know if you could tell me the dielectric strength of e-coat and the relationship with electrical isolation. Thank you in advance. K.F.B.

 

A. The dielectric strength of a material defines its capacity to withstand electrical fields without breaking down, and the formation of an electrically conductive path.

For a cured e-coat film, the value of the dielectric strength depends on the type and proportions or ratios of the specific resin and pigment used by your e-coat supplier, and to the degree or percentage of cure accomplished. For a normally cured automotive e-coat film, cathodic epoxy, black, and with a medium p/b ratio of 0.1 - 0.2, the dielectric constant of the cured film is 3.9 MVolts/meter. As a comparison, the dielectric constant of neoprene rubber is five times greater.

The more e-coat film you apply, the more electrical resistivity your electrical cabinets will have. Additionally, the resistance of the cabinet for voltage jumps will be increased.