Fiberglass vs. Polycarbonate Enclosures: The Battle of the Boxes

Fiberglass Enclosures compared to Polycarbonate

by Carl Marchese

The Battle of the Boxes

If you are reading this, you are probably wondering “Should I use a polycarbonate enclosure or a fiberglass enclosure?”  This is a very valid question to have.

Often we find companies continue to use fiberglass because they are unaware of the advantages of working with polycarbonate; and, the inherent value in using this versatile thermal set plastic.

When it comes to the NEMA type ratings, a 4X enclosure is a 4X enclosure when it leaves the factory, regardless of the material.  How well the enclosure performs during its service life, will determine your return on investment.

Today polycarbonate is one of the most versatile types of plastic used in industrial applications throughout the world for both indoor and outdoor applications.

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Impact Resistance

Polycarbonate can withstand an impact of over 900 psi; fiberglass comparatively can only withstand about 225 psi. As a thermoplastic, polycarbonate will flex and return to its original shape, while fiberglass can shatter with on impact.

Winner: Polycarbonate

UV Resistance

Delamination is a common problem and can eventually compromise the overall structural integrity of the enclosure – resulting in a system failure of the internal components.  Replacing either the enclosure or the entire unit may be required, costing time and money. is a common problem and can eventually compromise the overall structural integrity of the enclosure – resulting in a system failure of the internal components.  Replacing either the enclosure or the entire unit may be required, costing time and money.

Polycarbonate enclosures are injection molded and do not have layers to delaminate. The polycarbonate used for Fibox’s enclosures is specially formulated with UV inhibitors to withstand prolonged exposure to the sun.

Fibox took part in a UV exposure resistance study. The results showed that although a slight “bleaching effect” may occur over time, the Fibox polycarbonate enclosures became more durable in the field. This result is due to a chemical reaction that the polycarbonate has with the UV rays.

In some cases, Fibox clients have begun upgrading the internal components of their designs with a subsequent generation on-site while continuing to use their original enclosing investment. Recycling the enclosure saves time and money with a longer lasting Fibox enclosure.

Winner: Polycarbonate

Enclosure Modifications

Modifications

A stock enclosure dose does not remain stock for long, at some point, an engineer or technician will alter the box with holes, cutouts, and recesses. These changes are necessary to make the enclosures functional. Fiberglass and polycarbonate respond differently to such modifications.

Comprised of layers resin and glass fibers, Fiberglass when cut, drilled, or otherwise modified can splinter like wood, resulting in a rough, chipped edge (image 2). Delamination is a common problem and can eventually compromise the overall structural integrity of the enclosure – resulting in a system failure of the internal components.  Replacing either the enclosure or the entire unit may be required, costing time and money.

Moreover, the cutting process produces a dust containing glass particles. This dust can irritate the eyes and any exposed skin. Inhaling the dust can impact respiratory function. Handling fiberglass modifications require the user to “suit up” to ensure safety.

Conversely, modifying polycarbonate produces larger specks of material that are too heavy to become airborne. These specks will not irritate the skin and can be easily swept up or vacuumed. Additionally, if a window is required, this is easily accomplished with a polycarbonate enclosure. Polycarbonate offers many transparent cover options, or can easily install a polycarbonate window. (image 3).

Winner: Polycarbonate

Weight

Fiberglass outweighs polycarbonate by varying amounts. Fiberglass enclosures have thicker walls than a polycarbonate enclosure. For example, a 16x14x8 inch polycarbonate enclosure weighs 7.3 pounds. Compare that to a smaller sized, 16x14x6 inch fiberglass enclosure which weighs 8.9 pounds.

The costs associated with greater weight can go well beyond the initial shipping costs from the supplier’s warehouse until the unit arrives at its final destination. Shipping costs can quickly increase the overall product cost – not to mention the additional strain on human resources when carrying and installing heavier enclosures.

These costs are magnified when working with larger sized boxes. Using a polycarbonate enclosure will save money on shipping and human resources right off the bat.

Winner: Polycarbonate

Cost

Polycarbonate and fiberglass are comparably priced, however, with all the factors stated above fiberglass can cost you and your company more in time and money. These possible cost drivers include shipping, potential redoing modifications and a shorter, less reliable field life.

Winner: Polycarbonate

If you have any questions, or want to start increasing your productivity and profits, contact your local Fibox representative to learn more about Fibox polycarbonate enclosing solutions.