Ask the Expert Question-and-Answer Archive

by Ron Joseph

August, 2008

Electrical Equipment Paint Requirement

Q: A project specification calls for the electrical equipment to be factory finished with epoxy based paint. These days, all manufactures use a powder coating process. Is this just an outdated requirement? I am hesitating, because, the job is in an area near the Pacific coast, and maybe there is a concern about corrosion due to the proximity to the coat?

A: If the electrical equipment will be exposed to moist salt air near the coast, you certainly have the right to be fearful. However, if the equipment will be indoors your fear should be diminished. Having said that, the ability of the epoxy powder coating to withstand the environment depends on the type of substrate, (steel, galvanized steel or aluminum), surface preparation, (iron or zinc phosphate of steel and galvanized steel), conversion coating of aluminum), the presence or absence of a powder coating primer, and the film thickness of the epoxy topcoat. Without this information I can't comment on the specification.

If the specification is vague, you would need to know the environment in which the equipment will be exposed and the nature of the substrate so that you can offer a powder coating system that will satisfy your customer. The entire system should be specified, including surface preparation, primer (if necessary), topcoat and minimum dry film thickness. Be aware that some epoxy coatings tend to chalk when exposed to UV light especially in humid areas.

I hope this answers your question.

Regards,

Ron Joseph