By Bill DeRoche, Allied Moulded Products
The basic premise of an enclosure is simple – it is a cabinet to store electrical components to prevent shock to users and to protect the contents from the environment. The enclosure is essential for its utilitarian purposes, but should also fit aesthetically into its location.
There are a variety of choices available for the material and construction of enclosures. The two main categories are metal and nonmetallic. Metal enclosures can be made of carbon steel, stainless steel or aluminum. Carbon steel has an initial lower cost, but must be painted or coated to provide resistance to moisture and other corrosive environments. Regular maintenance is required for carbon steel enclosures.
Stainless steel and aluminum enclosures have a higher cost, yet there is less maintenance (to prevent rusting) than with the carbon steel variety. Features include strength, corrosion resistance, chemical resistance and a residual scrap value when the life of the enclosure has ended.
The primary nonmetallic materials are thermosets and thermoplastics. Thermoplastics are injection molded products, with polycarbonate and polyvinyl chloride (PVC) materials being the most common. These enclosures offer a degree of protection beyond painted carbon steel. They offer rigidity, durability, a lighter weight and non-conductivity. However, in outdoor environments they are more susceptible over time to the effects of UV and weathering degradation.
Fiberglass reinforced polyester (FRP) is an example of thermoset material. It provides greater corrosion protection than painted carbon steel and performs better than metal and thermoplastics in harsh, outdoor environments.
Although metal enclosures have been around the longest, there are a number of advantages to using nonmetallic enclosures. They have been proven especially reliable, providing longer life protection in both outdoor and indoor environments. There may be an initially higher cost over painted steel products, however, there is no maintenance required to prevent rusting. There is also a considerable savings over the premium metal enclosures. Aluminum is prone to oxidation and not recommended for all outdoor applications. Stainless steel products can rust over time, in addition to its limitations protecting against certain corrosive chemicals and harsh environments. Nonmetallic products will not rust. Another advantage of nonmetallic enclosures is the ease to modify, with modifications completed more quickly and without the need for expensive tools.
When considering the cost of an enclosure in relation to the overall solar project budget, enclosures should be considered more than just a box. One of the advantages of solar installations is the fixed cost of the solar energy system versus the utility-supplied electricity, which likely will increase over time. That fixed cost can be negatively impacted or increased if the protection an enclosure provides is compromised in any way and the controls inside are damaged or fail to function properly.
The resulting less-than-optimum system performance, including downtime and the expense to replace the enclosure, would result in final costs that are higher than if the correct enclosure had had been initially selected. This is why it’s important to understand that an enclosure is more than just a box; it is simply essential to your solar project.
Bill DeRoche is a graduate of Boston’s Northeastern University, with a degree in Business Administration. He has more than 30 years of experience in sales management at both a metal enclosure manufacturer as well as his current employer, Allied Moulded Products, manufacturer of nonmetallic enclosures.
Listen to an interview with Bill DeRoche here.