Grey vs Orange vs White vs Black Conduit: What’s the Difference

1.  Introduction

❓ Do you ever wonder about the difference between grey, orange, white and black conduits?

You’re not alone—many people aren’t sure why these colors exist, or what they’re really for.

🔧 The truth is: conduit colors usually mean something, and choosing the wrong one could lead to confusion, code violations, or costly rework.

🌏 It’s also worth noting that conduit color standards can vary between countries. What’s used for electrical wiring in one place might be used for communication systems elsewhere.

🧱 PVC conduits in particular tend to come in more varied colors compared to metal or steel conduits. This is largely due to the flexibility of the manufacturing process and the wide range of applications PVC is used for.

📍 In this post, we’ll focus on the typical practices in Australia and New Zealand, where conduit color coding is especially important for keeping projects compliant and organized.

📘 Whether you’re a contractor, engineer, or planning a project, this guide will help you clearly understand the difference between grey, orange, and black conduit—what they’re used for, and when to use each one.

The following table is based on AS 1345-1995, the Australian Standard for the identification of contents in pipes, conduits, and ducts.

➡️ Let’s begin with one of the most commonly seen options: grey conduit.

2. Grey Conduit: The Standard for General Electrical Wiring

In Australia and New Zealand, grey conduit is the most commonly used type for general electrical conduit applications.

⚙️ Grey conduits are typically manufactured to medium duty specifications, meaning they can withstand a compressive load of around 750 Newtons.

🏋️ This makes them strong enough for most standard installations where moderate mechanical protection is needed.

The mechanical strength balances durability with ease of handling and installation, making grey conduit a reliable choice for everyday electrical wiring.

3. Orange Conduit: Heavy-Duty Electrical Conduit for Underground Use

Orange PVC conduit is designed for electrical cables, particularly those that run underground or in outdoor environments.

In Australia and New Zealand, orange conduit is commonly used for underground electrical installations.

🟠 Its bright color helps clearly identify buried electrical routes and avoid accidental damage during excavation work.

Orange conduit is generally manufactured as Heavy Duty (HD), with a compressive strength of 1250 Newtons, in line with AS/NZS 2053 standards.

This ensures it can handle soil pressure, shifting ground, and mechanical impacts after installation.

4. White Conduit: For Telecommunications and Data Cabling

In Australia, white conduit is commonly used for telecommunications and data cable installations, especially in residential or commercial projects connected to the National Broadband Network (NBN).

⚪It is the standard color for identifying communication pathways separate from power cables.

White communication conduits are typically made to Medium Duty (MD) specifications, with a compressive strength of 750 Newtons.

This makes them suitable for most indoor and low-impact environments.

While strong enough for regular building applications, white conduit is not designed for underground or heavy mechanical stress, unless specifically upgraded.

5. Black Conduit: For Solar and Outdoor Electrical Installations

When it comes to solar systems and outdoor wiring, black conduit is the common choice in Australia.

⚫ Its standout feature is excellent UV resistance, which makes it suitable for environments exposed to direct sunlight and harsh weather conditions.

Most black conduit is made to Heavy Duty (HD) specifications, with a compressive strength of 1250 Newtons, in compliance with AS/NZS 2053.

This ensures it can handle physical impacts, UV degradation, and outdoor mechanical stress.

You might be asking: Why is black conduit commonly chosen for solar or outdoor use?

In short, black isn’t just a color—it’s part of the performance.

🛡️ UV Protection: Black PVC naturally absorbs UV rays more effectively and can be blended with higher amounts of carbon black, a pigment that provides strong UV resistance. This helps slow down material degradation in outdoor conditions.

🌦️ Heat Resistance: Black surfaces handle thermal cycling (heat during the day, cool at night) better than lighter-colored conduits. This is especially important on rooftops or in exposed environments.

👀 Easy Visual Identification: In Australia and New Zealand, black conduit is commonly understood on job sites as the standard for solar or outdoor electrical applications, helping avoid confusion with grey (general) or orange (underground) conduits.

6. Conclusion  

Choosing the right conduit color isn’t just about looks—it signals different uses, durability levels, and compliance with local standards.

In Australia and New Zealand, grey conduit is usually for medium duty electrical work, orange conduit for heavy duty underground, black conduit for outdoor and solar projects, and white conduit for telecommunications and data cables. 

Knowing these differences helps ensure safety and project success.

At Ctube, we specialize in providing high-quality PVC conduit, UPVC solar conduit, and LSZH conduits and fittings tailored to meet various industry needs.

With extensive experience and participation in numerous projects, we offer customized solutions backed by reliable certifications to support your electrical installations.

If you’re interested in learning more about our products or need expert advice, feel free to contact us anytime.

Thank you for reading! We hope this guide is helpful.

Wishing you great success in your electrical projects!

FAQs

☀️ Q1: Can You Use Grey Conduit Outdoors?

Yes, but with caution. While some grey conduits are suitable for outdoor use, they must be UV-rated. Standard grey conduit without UV protection can become brittle and discolored over time if exposed to direct sunlight.

👉 Always check the manufacturer’s specs or look for markings that indicate UV resistance if you’re using grey conduit in outdoor or partially exposed settings.

💡Q2: What’s the difference between medium duty and heavy duty conduit?

Medium duty conduit is rated to 750N and used for indoor or low-impact areas, like walls and ceilings.

Heavy duty conduit is rated to 1250N and designed for underground or outdoor use, where higher strength is needed.

👉The choice depends on your installation environment and compliance with AS/NZS 2053.

📚If you’re interested in learning more about the differences between HD and MD conduits, here a post for you: The Main Differences Between HD PVC Conduits and MD PVC Conduits in Australia.

🌐Q3: Is conduit color coding the same in every country?

No, conduit color coding varies by country or region. While some colors are commonly used, there’s no global standard.

Conduit colors in Australia and New Zealand typically align with the standards described above.

However, in the United States, conduit color coding may vary depending on the state, contractor, or utility company.

Typically, grey and white PVC conduits are used for electrical wiring, while blue or orange conduits are often designated for telecommunications and data cables.

📌 This information is for reference only. Always follow your local regulations and project specifications to ensure compliance and safety.