Plastic Electrical Enclosures: The Complete Guide for Industrial Applications
Plastic Electrical Enclosures Built for Harsh Industrial Environments
Today's electrical systems demand more from an enclosure than simply housing components. Modern installations must withstand moisture, corrosion, ultraviolet exposure, chemicals, vibration, washdowns, and extreme temperatures while protecting sensitive electronics for years of reliable operation.
For many OEMs, panel builders, system integrators, and electrical contractors, plastic electrical enclosures have become the preferred alternative to painted steel, stainless steel, and fiberglass. Advances in polycarbonate materials now provide exceptional durability while reducing weight, eliminating corrosion, and simplifying installation.
This guide explains everything you need to know about selecting the right plastic enclosure for industrial applications.
What Is a Plastic Electrical Enclosure?
A plastic electrical enclosure is a protective housing designed to safeguard electrical and electronic equipment from environmental hazards, accidental contact, dust, water, chemicals, and physical impact.
Unlike consumer-grade plastic boxes, industrial electrical enclosures are engineered to meet demanding standards such as UL, NEMA, and IP ratings. They are commonly used to protect:
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PLCs
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Variable Frequency Drives (VFDs)
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Power supplies
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Terminal blocks
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Relays
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Network switches
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Communication equipment
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Solar combiner components
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Building automation controls
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Instrumentation
Selecting the proper enclosure helps improve system reliability, extend equipment life, and reduce maintenance costs.
Why More Engineers Are Choosing Polycarbonate
Polycarbonate has become one of the most widely specified enclosure materials because it offers an excellent combination of strength, durability, and long-term environmental resistance.
Compared to many traditional enclosure materials, polycarbonate provides:
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High impact resistance
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Excellent UV stability
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Outstanding corrosion resistance
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Electrical insulation
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Lightweight construction
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Long service life
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Chemical resistance
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Excellent dimensional stability
Because polycarbonate does not rust or oxidize, it performs exceptionally well in coastal, wastewater, food processing, chemical processing, and outdoor installations.
Plastic vs Metal Enclosures
Metal enclosures have long been the industry standard, but they aren't always the best solution.
Plastic enclosures offer several important advantages.
| Plastic Enclosures | Metal Enclosures |
|---|---|
| Won't rust | Can corrode |
| Lightweight | Heavy |
| Electrically insulating | Conductive |
| RF transparent | Acts as a Faraday cage |
| Easier to machine | Requires metalworking |
| Lower maintenance | May require repainting |
| Resistant to many chemicals | Coatings can be damaged |
For wireless devices, IoT equipment, remote monitoring, and modern industrial automation, RF transparency has become a major benefit because antennas can often remain inside the enclosure without significantly reducing signal strength.
Plastic vs Fiberglass
Fiberglass has traditionally been selected for corrosive environments, but modern polycarbonate offers several advantages.
Polycarbonate typically provides:
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Better impact resistance
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More consistent dimensional accuracy
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Lower weight
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Cleaner appearance
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Easier machining
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Transparent cover options
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Improved aesthetics
Fiberglass remains a good option for certain applications, but many engineers now specify polycarbonate for new installations because it combines strength with easier fabrication.
Indoor vs Outdoor Applications
Not every enclosure is designed for outdoor use.
Outdoor electrical enclosures should provide protection against:
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Rain
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Snow
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Ice
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UV exposure
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Dust
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Wind-driven water
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Temperature fluctuations
UV-stabilized polycarbonate helps maintain appearance and mechanical performance during long-term outdoor exposure, making it well suited for applications such as:
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Solar energy
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Traffic systems
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Water treatment
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Telecommunications
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Utility infrastructure
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Security systems
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Building automation
Understanding NEMA Ratings
NEMA ratings describe how well an enclosure protects equipment from environmental hazards.
Common industrial ratings include:
NEMA 4
Protection against rain, splashing water, hose-directed water, and dust.
NEMA 4X
Adds corrosion resistance for harsh industrial environments.
NEMA 6
Provides protection during temporary submersion.
NEMA 6P
Provides protection during prolonged submersion under specified test conditions while maintaining environmental integrity.
Choosing the correct NEMA rating ensures the enclosure matches the installation environment.
IP Ratings
Many global projects also reference IEC IP ratings.
Common ratings include:
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IP65
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IP66
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IP67
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IP68
NEMA and IP ratings address similar environmental concerns but are based on different testing standards.
Industries That Benefit from Plastic Enclosures
Plastic electrical enclosures are used across numerous industries, including:
Solar Energy
Protecting combiner boxes, disconnects, monitoring equipment, trackers, and battery storage systems.
Industrial Automation
Housing PLCs, HMIs, sensors, motor controls, and communication equipment.
Water and Wastewater
Providing corrosion-resistant protection around chemicals, washdowns, and humid environments.
Building Automation
Protecting HVAC controls, access control systems, lighting controls, and security equipment.
Telecommunications
Supporting wireless infrastructure while allowing RF signals to pass through non-metallic enclosures.
Transportation
Protecting signaling, communications, and control equipment in demanding outdoor environments.
Factory Modifications Save Time
Many manufacturers now offer value-added services that eliminate secondary machining operations.
Common factory modifications include:
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CNC machining
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Custom cutouts
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Printing and labeling
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DIN rail installation
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Assembly services
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Custom hardware
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Cable gland installation
Factory machining helps reduce labor while maintaining enclosure integrity and consistency.
Choosing the Right Size
Selecting the correct enclosure involves more than fitting today's components.
Consider:
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Future expansion
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Cable bend radius
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Heat generation
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Mounting hardware
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Service access
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Door clearance
Providing additional room often simplifies maintenance and future upgrades.
Frequently Asked Questions
Are plastic electrical enclosures waterproof?
Many are designed to resist water intrusion when properly installed. Always verify the enclosure's NEMA or IP rating for your application.
Are plastic enclosures suitable for outdoor use?
Yes. UV-stabilized polycarbonate enclosures are widely used in demanding outdoor environments.
Do plastic enclosures rust?
No. Polycarbonate does not rust or corrode like steel.
Can plastic enclosures replace stainless steel?
In many applications, yes. Polycarbonate offers excellent corrosion resistance, lighter weight, and easier installation while remaining electrically insulating.
Are plastic enclosures good for wireless equipment?
Yes. Unlike metal enclosures, polycarbonate does not create a Faraday cage, allowing wireless signals such as Wi-Fi, Bluetooth, cellular, and LoRa to pass with far less attenuation.
Can enclosures be customized?
Yes. Many manufacturers offer factory CNC machining, printing, assembly, and accessory installation.
Why choose a UL Listed enclosure?
A UL Listed enclosure has been evaluated as a complete product to meet applicable safety standards, providing confidence for engineers, installers, inspectors, and end users.
Why Fibox Polycarbonate Enclosures?
Fibox has spent decades developing non-metallic enclosure solutions for demanding industrial applications. Fibox polycarbonate enclosures are designed to deliver long-term performance in corrosive, outdoor, and washdown environments while supporting modern electrical and automation systems.
Available across multiple product families, Fibox enclosures offer solutions ranging from compact junction boxes to large industrial cabinets, with options for factory machining, direct printing, custom assembly, and a broad selection of accessories.
Whether your application involves solar energy, industrial automation, water treatment, transportation, telecommunications, or building automation, selecting the right enclosure helps protect valuable equipment while reducing maintenance and extending service life.
Ready to Specify the Right Enclosure?
Explore the complete Fibox enclosure portfolio or contact our enclosure specialists for assistance selecting the best solution for your application. Our team can also provide factory machining, printing, and assembly services to help reduce installation time and simplify your next project.