• Corrosion Protection - Mild Steel/Powder Coat
• Corrosion Resistance of Various Enclosure Materials
• Suggest Applications for Corrosion Resistant Enclosures
• Pre-Treatment and Paint Process
• Powder Coating Reference Chart

Users of older Hammond Manufacturing catalogs will have noticed a change to the ratings noted for Type 4 painted mild steel enclosures. Previously, Hammond catalogs have shown that these enclosures also carried the Type 4X designation, but this is no longer noted in the catalog. There has been NO CHANGE WHATSOEVER to the quality of the Hammond paint Finish.

Hammond has removed the 4X approval from the catalog only to avoid mis-application of painted steel enclosures. The testing criteria for Type 4X is not as rigorous as many users may assume. It is important for users to understand the NEMA 4/4X rating. In response to concern about the costs of corrosion, the Underwriters’ Laboratory (UL) and the National Electrical Manufacturers’ Association (NEMA) have developed a rating system for electrical enclosures, stipulating that certain minimum conditions of corrosion resistance be met. Material tested to UL1332 (type 4 protective coating) is prerequisite to a type 4X salt spray test.

The NEMA 4X rating is applied to material that has met, under laboratory conditions, a six hundred hour salt spray with no worse pitting than that exhibited on a Type 304 Stainless sample run at the same time. This rating, however, does not test for corrosion resistance beyond this, or with chemicals other than salt.