Engineer’s Practical Guide • Eterna Global Solutions

How to Select the Right Industrial Electrical Enclosure

A step-by-step selection guide for enclosure size, indoor vs outdoor installation, IP/NEMA ratings, material choice, and thermal management — written for engineers & procurement teams.

Made for OEMs • Panel Builders • EPC Focus: Export-ready builds Updated:

Use the Selection Tool Request Custom Enclosure

Why enclosure selection matters

Incorrect enclosure specification is a frequent root cause of field failures — overheating, corrosion, water ingress, gasket failure, and certification issues. If the enclosure is selected late in the design, you’re often forced into compromises that increase cost and risk.

Practical approach: Select the enclosure first (environment + thermal), then place electronics inside it.

Indoor vs Outdoor: selection rules

“Outdoor” is not just rain. Sunlight, humidity cycles, dust load, and corrosion are usually the real killers. If your equipment can ever see direct sunlight, humidity, or washdown exposure, treat it as an outdoor application.

Indoor applications

Dust control + filtered ventilation
Service access + cable routing
Thermal management (fans often enough)

Outdoor applications

UV + rain + humidity cycles
Corrosion resistance matters
Sun load may require AC / heat exchanger

Decision rule: If direct sunlight or rain is possible at any time → design as outdoor.

IP Rating vs NEMA Rating: what’s the difference?

IP ratings focus on ingress protection (dust/water). NEMA ratings (common in the US) include broader environmental considerations and test conditions. Many teams get stuck converting them — the key is to match the real exposure.

IP Rating	Typical protection	Common use
IP54	Dust-protected + splashing water	Indoor industrial
IP55	Dust-protected + water jets (limited)	Workshops / covered outdoor
IP65	Dust-tight + water jets	Outdoor (general)
IP66	Dust-tight + powerful water jets	Heavy rain / washdown

Quick equivalence (practical): NEMA 4 ≈ IP66. NEMA 4X ≈ IP66 + corrosion protection.

Material selection (CRCA vs Galvanized vs SS304 vs Aluminum)

Material choice drives corrosion performance, durability, weight, and total cost of ownership. Below is a practical selection logic used by many OEMs.

CRCA Steel (Powder Coated)

Cost-effective for indoor environments. Ensure correct pre-treatment + coating thickness.

Galvanized Steel (GI)

Best general-purpose option for outdoor industrial use. Strong balance of cost + corrosion resistance.

Stainless Steel 304

Preferred for food/pharma, coastal, high-corrosion zones, and washdown-prone environments.

Aluminum

Lightweight and corrosion-resistant; common in telecom/solar where weight and handling matter.

Most common “sweet spot”: For outdoor industrial applications, galvanized steel often delivers the best balance of durability and cost.

Enclosure sizing: the engineer’s method

A reliable sizing rule is to keep electronics at ≤ 60% of the internal usable volume to allow air circulation, service clearances, and thermal headroom.

Rule: If you can’t route cables or place airflow paths without crowding, the enclosure is undersized — even if “it fits.”

Thermal decision (quick logic)

ΔT ≤ 10°C: filtered fan ventilation is usually sufficient
ΔT 10–20°C: intake + exhaust fan strategy + better airflow path
ΔT 20–30°C: consider heat exchanger (sealed) or higher airflow
ΔT > 30°C: enclosure AC / active cooling is recommended

Interactive enclosure selection tool (no cost — only spec guidance)

Choose your environment and constraints. This tool outputs a practical recommendation you can use as a starting point for a proper datasheet/spec.

Installation environment

Dust level

Estimated heat load (rough)

Preferred mounting

Suggested protection: —

Suggested material: —

Cooling direction: —

Get a custom enclosure recommendation Jump to ordering checklist

Cooling & ventilation: avoid the most common failure

Most enclosure failures are thermal failures, not electrical failures. Good design means controlled airflow paths, correct filter selection, and sealing strategy that matches your IP/NEMA requirements.

Key principle: If you need a sealed enclosure (high IP), a heat exchanger or AC is often safer than “adding more fans”.

Pre-order checklist (use this before sending RFQ)

Environment

Indoor / Outdoor / Washdown / Coastal
Ambient temperature range
Dust load and cleaning method

Electrical & thermal

Heat load estimate (W)
Ventilation allowed or sealed required
Fan/Filter/AC requirement

Mechanical

Mounting type: wall / floor / pole
Cable entry side + gland plate
Service access and door swing

Compliance

Target rating: IP / NEMA
Material requirement (GI / SS / Al)
Finish requirement (powder coat / SS brush)

Request a custom enclosure recommendation

Share the basics below — we’ll recommend a starting spec (IP/NEMA, material, ventilation direction, and form factor).

Name

Company

Phone (optional)

Project details (environment, size, heat load, quantity)

FAQ

What is the most common enclosure mistake? +

Choosing the enclosure after finalizing electronics. This often leads to poor airflow, undersized volume, and wrong ingress/corrosion protection — increasing failures and redesign cost.

Is IP65 always enough for outdoor? +

For general outdoor rain exposure, IP65 is commonly used. For heavy rain, washdown, or directed water jets, IP66 (or higher) is safer. Always match to your real exposure conditions.

When should I use stainless steel 304? +

Use SS304 for coastal/high-corrosion zones, food/pharma environments, and frequent washdown. It improves corrosion resistance and long-term appearance compared to coated mild steel.

Fans vs AC — how do I decide quickly? +

If your enclosure must remain sealed (high IP) and heat is moderate-to-high, AC/heat exchanger is usually better. Fans are effective when you can allow ventilation and control dust with proper filters.