Standard Distribution Box Materials

Distribution boxes are commonly made from metals like steel and aluminum, plastics such as polycarbonate and PVC, and fiberglass, each chosen for durability, fire resistance, and environmental suitability.

Metal Materials

Steel is widely used for its strength and impact resistance, making it ideal for high-voltage, industrial, or outdoor applications. It can be galvanized or stainless to resist corrosion in wet or salty environments and provides shielding against electromagnetic interference. Aluminum is lighter than steel, naturally corrosion-resistant, and suitable for damp or outdoor locations, offering easier handling without compromising durability .

Plastic Materials

Polycarbonate (PC) and PVC are common thermoplastics used for indoor or low-voltage distribution boxes. They are lightweight, non-corrosive, and can be flame-retardant, often rated according to UL 94 standards. Thermoset plastics like SMC (Sheet Molding Compound) provide high mechanical strength, fire resistance, and stability in harsh environments .

Fiberglass and Composite Materials

Fiberglass-reinforced plastics are used in corrosive or marine environments due to their excellent resistance to rust, chemicals, and UV exposure. These materials maintain structural integrity under prolonged outdoor conditions and are often selected for industrial or coastal installations .

Key Considerations

• IP Ratings: Indicate protection against dust and water; higher ratings (IP65–IP67) are essential for outdoor or wet locations .
• Fire Resistance: Materials should prevent fire spread and protect internal circuits, especially in residential and industrial settings .
• UV Resistance: Important for outdoor boxes to prevent brittleness or discoloration over time .
• Environmental Suitability: Stainless steel or coated metals and thermoset plastics are preferred in corrosive or chemical-prone areas . Selecting the right material ensures safety, longevity, and compliance with standards such as NEC and OSHA, while matching the box to its intended environment and electrical load .