Plastic Casing Vs. Metal Casing: A Complete Comparative Analysis of B2B Procurement

This article covers the following content.

If you are an electrical wholesaler or EPC procurement officer selecting enclosure materials for your project, this article will help you figure it out:

1️⃣ What are the differences between plastic, stainless steel, and aluminum?

2️⃣ Comprehensive comparison across five core dimensions (cost, corrosion resistance, weight, heat dissipation, and strength)

3️⃣ Quickly locate the material orientation based on the application scenario

4️⃣ The 5 most common material selection problems in procurement

This article was written by the BSUMWELL technical team. We are a manufacturer specializing in waterproof electrical enclosures, with products covering three major material series: PC/ABS plastic, stainless steel, and aluminum enclosures, with protection levels ranging from IP55 to IP68. We also support OEM/ODM customization.

Plastic vs. Metal: Why is material selection the most important decision in casing procurement?

The cost of choosing the wrong material – real-world scenarios

An EPC contractor used ordinary ABS plastic casing in a coastal photovoltaic project to reduce BOM costs. As a result, in less than two years, the plastic severely powdered and cracked due to the combined effects of high-intensity ultraviolet radiation and salt spray, and rainwater backflow burned out the internal inverter.

The initial 30% savings in the procurement budget led to tens of thousands of dollars in equipment damage claims.

This is not an isolated case. In the procurement of electrical enclosures, material selection is the decision most easily misled by the "initial price" — and it is also the decision that should least be based solely on the initial price.

Different materials vary greatly in cost, corrosion resistance, weight, heat dissipation, strength, and processability. Choosing the wrong material might save you a little money, but cost you a lot more.

Three main materials: plastic, stainless steel, and aluminum

There are currently three main types of electrical enclosure materials on the market:

Our product line covers all three material series, with protection levels ranging from IP55 to IP68. No matter the environment or specific requirements of your project, you can find the appropriate material option.

Selection Recommendation Summary

• Coastal/Chemical → Stainless steel (316)

• Outdoor environment → PC/ABS plastic (UV resistant)

• High-heat equipment → Aluminum casing

• Corrosion-resistant and lightweight required → Aluminum casing (ocean-grade coating)

Plastic vs. Metal Casing: A Comprehensive Comparison Across Five Key Dimensions

Initial Costs – Which is Cheaper?

Initial cost conclusion: plastic is the cheapest, stainless steel is the most expensive. But the initial price is just the tip of the iceberg—the total life cycle cost is the real accounting.

Corrosion resistance – which is more corrosion resistant?

Corrosion resistance conclusion: Stainless steel is the strongest, plastics have zero corrosion but require UV resistance, and aluminum relies on coating protection.

Key reminder: Ordinary ABS will age within 1-2 years under direct outdoor sunlight (industry-standard data based on UL 746C outdoor aging test standard). UV-resistant PC/ABS can extend its lifespan to 10-15 years (industry-standard data based on ASTM G154 QUV test). When choosing a plastic casing, be sure to check whether UV stabilizers have been added.   Learn about PC/ABS plastic housing products

Weight vs. Installation – Which is Easier?

Weight conclusion: Plastic is the lightest, followed by aluminum, and stainless steel is the heaviest.

Installation hidden cost reminder

While stainless steel casings offer high strength (IK10, according to IEC 62262 standard), their weight is significant—making the costs of bracket reinforcement, high-altitude hoisting, and manual handling negligible. In pole-mounted or high-altitude operations, the weight advantage of aluminum and plastic casings can significantly reduce overall installation costs. View our stainless steel casing product series

Heat dissipation performance – which is better suited for heat-generating devices?

Heat dissipation conclusion: Aluminum casing provides optimal heat dissipation and is the preferred choice for high-heat-generating equipment such as frequency converters, drives, and communication base stations. Plastic is a thermal insulator, so high-power-consumption internal components require careful heat dissipation design. View our aluminum casing product series

Mechanical strength vs. grounding – which is safer?

Strength and safety conclusions:

• Metal casings (stainless steel/aluminum) offer greater impact resistance and inherent electromagnetic shielding capabilities—making them suitable for environments with strong electromagnetic interference, such as those used in frequency converters and PLC control cabinets.

• The plastic casing provides insulation and eliminates the need for grounding—saving time on grounding work, but it's not suitable for scenarios requiring EMI shielding.

• Plastics must meet UL 94 V-0 flame retardancy standards; metals are naturally non-flammable and automatically comply with regulations.

Selection Recommendation Summary

• EMI shielding required → Metal casing (aluminum/stainless steel)

• IK10 is required to withstand impact. → Stainless steel or thickened PC

• Groundless application required → Plastic casing

Comparison of the advantages and disadvantages of the three materials

The core positioning of the three materials:

• PC/ABS plastic: Zero corrosion, lowest cost, lightest weight – suitable for general outdoor and inland environments and scenarios requiring insulation.

• Stainless steel: Strongest corrosion resistance and longest lifespan – suitable for highly corrosive environments such as coastal areas, chemical plants, and offshore areas.

• Aluminum casing: Optimal heat dissipation, lightweight yet strong – suitable for heat-generating equipment such as photovoltaic inverters, energy storage cabinets, and frequency converters.

Shell Material Selection Guide: Quickly Determine the Material Direction Based on Application Scenarios

Quick Reference Table for Material Selection Based on Application Scenarios

How do I use this table?

1️⃣ Identify your application scenario

2️⃣ Find the corresponding recommended material in the table.

3️⃣ Check if there are any additional notes in the Special Requirements section.

4️⃣ For customization, please contact customer service to confirm the plan.

The above selections are general suggestions only. For material selection support tailored to specific projects, please contact our technical team — we can provide a free selection assessment based on your project environment and needs. Contact us for material selection advice.

Material selection decision-making process based on procurement needs

Three steps to lock material orientation:

• Step 1: In what environment is the project located?

• Coastal/Chemical Industry → Stainless Steel

• General outdoor use → PC/ABS plastic or aluminum

• Indoor → PC/ABS plastic is sufficient

• Step 2: Does the equipment generate a lot of heat?

• High heat generation (inverter/power supply) → Aluminum casing

• Low heat generation → Can be made of plastic or stainless steel

• Step 3: Is EMI shielding required?

• Requires → Metal casing (aluminum/stainless steel)

• No need → Plastic casing is sufficient

Our product line covers IP55-IP68, with materials including PC/ABS plastic, stainless steel, and aluminum housings, allowing for flexible matching to project requirements. View the full range of waterproof housing products

Frequently Asked Questions (FAQ) about Procurement

Frequently Asked Questions Quick Answers

Q: How many years can a plastic shell last outdoors?

A: Ordinary ABS will age within 1-2 years under direct outdoor sunlight (industry-standard data based on UL 746C outdoor aging test standard). UV-resistant PC/ABS can extend its outdoor lifespan to 10-15 years. When selecting a product, be sure to confirm whether UV stabilizers have been added to the material.

Q: Which is more corrosion resistant, stainless steel or aluminum casing?

A: Stainless steel (especially 316) offers far superior corrosion resistance compared to aluminum casings. 316 stainless steel contains molybdenum, which helps it withstand marine salt spray and chemical media. Aluminum casings rely on coatings for protection, and pitting corrosion can occur once the coating is damaged.

Q: Must metal casings be grounded? Are plastic casings safer because they don't need to be grounded?

A: The metal casing is a conductor and must be reliably grounded; otherwise, the casing may become charged if the internal insulation fails. The plastic casing is an insulator and does not require grounding. However, the metal casing naturally possesses electromagnetic shielding capabilities, while the plastic casing does not.

Q: When doing OEM customization, which is more cost-effective, plastic or metal?

A: It depends on the batch size.

• Small batch/multiple varieties → Metal (aluminum profiles/sheet metal) mold-free, fast delivery

• Mass production/standardization → Extremely low unit price after plastic mold making

Q: What materials do your products cover?

A: Our product line covers three major material series:

• PC/ABS plastic housing: suitable for general outdoor and inland environments.

• Stainless steel casing: suitable for highly corrosive environments such as coastal areas and chemical plants.

• Aluminum casing: Suitable for high-heat devices and applications requiring heat dissipation.

Protection levels range from IP55 to IP68.

Summary of the key points of this article

1️⃣ Each of the five materials has its own advantages and disadvantages. Plastics are non-corrosive but require UV resistance; stainless steel offers the best corrosion resistance but is expensive; aluminum provides the best heat dissipation but relies on coatings.

2️⃣ Comprehensive comparison across five dimensions — Cost, corrosion resistance, weight, heat dissipation, strength + grounding

3️⃣ Lock materials by scene — Stainless steel for coastal/chemical applications, aluminum for high-heat applications, and PC/ABS for general outdoor use.

4️⃣ Initial cost ≠ total cost — When selecting materials, consider the entire life cycle, not just the purchase price.

5️⃣ Our products cover three materials. — IP55-IP68, flexible to match project requirements

(Next article preview: Having learned the basic comparison of the three materials? Next, let's look at how to choose for specific application scenarios—what materials are used in coastal areas/chemical industries/photovoltaics/charging piles? Please read the second article in this series, "Scenario-Based Selection Guide: Coastal Areas, Chemical Industries, Photovoltaics, Charging Piles—Selection of Shell Materials for Different Application Scenarios."):  Contact us for material selection advice.