Posted on by Carl Marchese
Is Polycarbonate a Metal? Understanding This Engineering Plastic
Quick answer
No. Polycarbonate is a thermoplastic polymer, not a metal. It is used for electrical enclosures because it combines high impact toughness, low weight, electrical insulation and corrosion resistance. Depending on the application, those properties can make it a practical alternative to steel, stainless steel, aluminum or fiberglass.
What is polycarbonate?
Polycarbonate is an engineered plastic whose molecular structure includes carbonate groups. It can be molded into complex, repeatable shapes and produced in opaque or transparent grades. Manufacturers can tailor formulations for ultraviolet exposure, flame performance, color, impact behavior and other requirements.
Why does it sometimes feel like a metal replacement?
A molded polycarbonate enclosure can perform many of the same protective functions as a fabricated metal box: it houses electrical and electronic components, limits access to hazardous parts and protects equipment from environmental exposure. It is therefore often compared with metal, even though its physical and electrical properties are very different.
Polycarbonate does not rust
Because polycarbonate contains no iron, it cannot rust. It can still be affected by incompatible chemicals, ultraviolet exposure if the wrong grade is used, excessive heat or poor mechanical design. “Corrosion resistant” should therefore be understood in relation to the specified environment, not as a promise that every plastic tolerates every chemical.
Polycarbonate is electrically insulating
Unlike steel or aluminum, polycarbonate does not conduct electricity under normal enclosure-use conditions. This can reduce certain grounding and bonding concerns associated with a conductive housing, although the finished electrical system must still comply with all applicable wiring, grounding and safety requirements.
Is it as rigid as metal?
No. Polycarbonate has lower stiffness and tensile strength than steel. It will flex more under load. In many enclosure applications, that controlled flexibility is useful because it can absorb impact and recover instead of denting or cracking. In applications dominated by structural loads or extreme rigidity, metal may be the better choice.
Polycarbonate versus fiberglass
Both are nonmetallic and corrosion resistant, but they behave differently. Polycarbonate is a thermoplastic; typical fiberglass enclosures use a thermoset resin reinforced with glass fibers. Polycarbonate can provide a smoother surface, cleaner machining and strong impact performance. Fiberglass can offer stiffness and chemical resistance in certain environments, but machining may expose fibers and damaged areas can crack rather than flex.
Where polycarbonate enclosures are used
Common applications include industrial automation, water and wastewater controls, renewable-energy equipment, telecommunications, monitoring systems, machine controls, building systems and outdoor junction boxes. UV-stabilized grades and suitable NEMA or IP ratings are important when the enclosure will face sun, rain, washdown, dust or temporary submersion.
Sources for technical review
Fibox Polycarbonate Enclosures VS. Fiberglass
POLYVANTIS LEXAN Polycarbonate Datasheet