Why do more and more charging pile projects specify the use of 304 stainless steel distribution boxes?

I. Harsh Working Conditions of Charging Pile Distribution Boxes

Electric vehicle charging piles are usually installed in outdoor parking lots, on the ground of residential areas, in highway service areas, and even in coastal regions. Their accompanying distribution boxes are exposed to complex environments all year round.

• Dampness and rain: Direct exposure to rain and condensation caused by temperature differences between day and night
• Salt spray erosion: In coastal cities or areas where de-icing agents are sprayed in winter, the salt content in the air is high
• High-temperature exposure: The temperature inside the box can reach over 60℃ in summer
• Dust and exhaust gas: Roadside charging piles are affected by vehicle exhaust and road dust
• Human vandalism: High requirements for anti-theft and anti-prying

Traditional carbon steel distribution boxes (with surface plastic spraying) often start to rust within 2 to 3 years in such harsh environments, leading to a decline in protection levels, damage to internal components, and even safety accidents. Therefore, an increasing number of operators and engineering contractors explicitly require the use of 304 stainless steel distribution boxes when making purchases.

II. Why 304 stainless steel?

304 stainless steel contains 18% chromium and 8% nickel, which can form a dense chromium oxide passivation film on the surface, preventing oxygen and moisture from coming into contact with the substrate. Even if the passivation film is scratched, it will quickly self-repair in the air. In the neutral salt spray test (NSS), 304 stainless steel can withstand over 1,000 hours without developing red rust, while ordinary carbon steel spray-painted parts usually can only endure 72 to 240 hours.

For coastal charging piles or areas where salt is spread in winter, the resistance of 304 stainless steel to chloride ion corrosion is far superior to that of 201 stainless steel, effectively preventing pitting and crevice corrosion.

III. Actual case: The effect was remarkable after replacing the 304 stainless steel distribution box at the coastal charging station

In a coastal city in southern China, the bus charging stations initially used carbon steel spray-painted distribution boxes in early 2021. Within less than two years, large areas of rust appeared at the bottom and welds of the boxes, and some box doors could not be closed properly.

Rust on the internal circuit breaker terminals led to poor contact. In 2023, the operator replaced all the distribution boxes with 304 stainless steel ones produced by Ouyue Electric (1.5mm thickness, IP65 protection grade, and surface RAL 7035 spray coating). After two rainy seasons and one typhoon, there was no rust on the boxes, the interiors were dry and clean, and the failure rate dropped by over 90%.

IV. Four key points for choosing a 304 stainless steel distribution box for charging piles

• Verify the authenticity of the material: Request the supplier to provide material proof.
• Sheet thickness: It is recommended that the main body be 1.5mm and the door panel be over 1.2mm to ensure strength.
• Protection grade: At least IP54. IP65 is recommended for coastal areas with abundant rainfall.
• Welding process: Outdoor boxes must be continuously and fully welded. Spot welding is not allowed. The weld seams need to be ground smooth.

V. Ouyue Electric: Specializing in customizing 304 stainless steel charging pile distribution boxes

China Ouyue Electric Co., Ltd. specializes in manufacturing 304 stainless steel charging pile distribution boxes. The plates are made from 304 coil materials from steel mills and processed through multiple procedures such as laser cutting, CNC bending, continuous full welding, and surface brushing/spraying. 

The product's protection level can reach IP65 and supports customization of various sizes and reserved positions for internal components. We have supplied in bulk to many domestic charging pile brands and customers in South Korea and Southeast Asia. We welcome charging pile operators, engineering companies, and traders to consult and customize with drawings and samples.