Two Shades of Grey – in the Data Center

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We live in a very colorful world.  However, when you step into the electrical equipment room in most data centers, you usually find one dominant color: grey. To be more precise, there are actually two shades of grey, ANSI 49 and ANSI 61.  Given the spectrum of possible colors, why is grey the standard?

To understand why grey is the standard, the origins of electrical equipment, specifically switchgear, should be considered.  The most primitive forms of switchgear, such as knife switches, are as old as electricity generation, dating back to the nineteenth century.  As the electrical utility industry evolved to accommodate rapidly escalating power levels and voltages, switchgear followed the industry trends and standards to keep pace.  As the utility market standardized equipment on the color grey, so did switchgear.

Today, specific color standards have been identified by leading trade associations. The American National Standards Institute (ANSI) and the Institute of Electrical and Electronics Engineers (IEEE) defined the standard for metal enclosed low voltage power circuit breaker switchgear via the 2002 edition of C37.20.1: The preferred color for the finish on switchgear assemblies shall be light gray No. 61 in accordance with ASTM D1535-1997.

While switchgear color is based on the standards of the utility industry, switchgear in a data center could be any color. However, even with paint color options available, most still choose the standard grey.  Several reasons dictate this selection.


One of the strongest motivators is cost. Painting of electrical distribution equipment is a lengthy process, involving multiple stages of cleaning, phosphatizing, paint application, and thermal curing.  Further, strict quality control measures are used to assure the consistent attributes of the cured paint.  Specific paint properties need to be retained, including hardness adhesion, gloss, film thickness, and humidity tolerance.  To meet these requirements, the paint application process has been standardized, leading to the standardization of the color as well.  However, switchgear can be painted special colors to meet a customer’s specifications by adding another step to the paint process – which adds cost, complexity and lead time.

From an aesthetics perspective, some specifically choose grey products to assimilate with other equipment.  Because most manufacturers standardize on grey, products from various vendors integrate and blend together more seamlessly with shades of grey. Still, some in the data center space recognize the need and purpose for color.  For instance, certain cloud provider locations have brightly painted pipe lines because it is visually appealing and provides a designation as to which one is which.

With its roots in the utility industry, electrical distribution equipment has dramatically evolved over the past 100 years.  Yet, its color remains the same. As the data center industry influences the innovations of power equipment, perhaps it can also add color as well.

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