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Conduit Fill Table: Your Guide to Sizing Conduits
WARNING
For electrical work, consult a licensed electrician or the NEC for safety. Licensed electricians are well-versed in the NEC, state, and local codes.
Selecting the right conduit size in electrical installations is essential for safety and functionality. Our comprehensive conduit fill chart simplifies this process, offering recommended sizes for various wire types, including EMT, IMC, Rigid, and Flexible Metal conduit. It's important to prevent overcrowding and ensure optimal performance. Conduit fill charts are invaluable when online tools are unavailable.
How to Use a Conduit Fill Chart
Using a conduit fill chart is straightforward and helps determine how many wires can safely fit inside a given conduit without exceeding a 40% fill rate.
Identify Your Conduit Type and Size:
Locate your conduit type and size in the first column. Follow these three steps.
- Determine the Wire Gauge: Find the wire gauge you intend to use along the top row.
- Find the Maximum Wire Count: The point where the chosen row and column intersect will indicate the maximum number of wires that can be accommodated.
- Verification: Verify that the fill rate is correct and ensure compliance with the 40% fill rate limit.
| Conduit Trade Size in Inches |
Wire Size (THWN, THHN) Conductor Size | |||||||||||||||||||||||
| AWG | MCM (kcmil) | |||||||||||||||||||||||
| 14 | 12 | 10 | 8 | 6 | 4 | 3 | 2 | 1 | 1/0 | 2/0 | 3/0 | 4/0 | 250 | 300 | 350 | 400 | 500 | 600 | 700 | 750 | ||||
| 1/2 | EMT Conduit | 12 | 9 | 5 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | |||||||||||||
| IMC Conduit | 14 | 10 | 6 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||||
| Rigid Conduit | 13 | 9 | 6 | 3 | 2 | 1 | 1 | 1 | 1 | |||||||||||||||
| Flexible Metal | 13 | 9 | 6 | 3 | 2 | 1 | 1 | 1 | 1 | |||||||||||||||
| 3/4 | EMT Conduit | 22 | 16 | 10 | 6 | 4 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||
| IMC Conduit | 24 | 17 | 11 | 6 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||
| Rigid Conduit | 22 | 16 | 10 | 6 | 4 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||
| Flexible Metal | 22 | 16 | 10 | 6 | 4 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||
| 1 | EMT Conduit | 35 | 26 | 16 | 9 | 7 | 4 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||
| IMC Conduit | 39 | 29 | 18 | 10 | 7 | 4 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||
| Rigid Conduit | 36 | 26 | 17 | 9 | 7 | 4 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||
| Flexible Metal | 33 | 24 | 15 | 9 | 6 | 4 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||
| 1 1/4 | EMT Conduit | 61 | 45 | 28 | 16 | 12 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||
| IMC Conduit | 68 | 49 | 31 | 18 | 13 | 8 | 6 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||
| Rigid Conduit | 63 | 46 | 29 | 16 | 12 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| Flexible Metal | 52 | 38 | 24 | 14 | 10 | 6 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||
| 1 1/2 | EMT Conduit | 84 | 61 | 38 | 22 | 16 | 10 | 8 | 7 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||
| IMC Conduit | 91 | 67 | 42 | 24 | 17 | 11 | 9 | 7 | 5 | 4 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||
| Rigid Conduit | 85 | 62 | 39 | 22 | 16 | 10 | 8 | 7 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||
| Flexible Metal | 76 | 56 | 35 | 20 | 14 | 9 | 7 | 6 | 4 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||
| 2 | EMT Conduit | 138 | 101 | 63 | 36 | 26 | 16 | 13 | 11 | 8 | 7 | 6 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | ||
| IMC Conduit | 149 | 109 | 69 | 39 | 28 | 17 | 15 | 12 | 9 | 8 | 6 | 5 | 4 | 3 | 3 | 2 | 2 | 1 | 1 | 1 | 1 | |||
| Rigid Conduit | 140 | 102 | 64 | 37 | 27 | 16 | 14 | 11 | 8 | 7 | 6 | 5 | 4 | 3 | 3 | 2 | 2 | 1 | 1 | 1 | 1 | |||
| Flexible Metal | 135 | 98 | 62 | 35 | 25 | 16 | 13 | 11 | 8 | 7 | 6 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | |||
| 2 1/2 | EMT Conduit | 241 | 176 | 111 | 64 | 46 | 28 | 24 | 20 | 15 | 12 | 10 | 8 | 7 | 6 | 5 | 4 | 4 | 3 | 2 | 2 | 1 | ||
| IMC Conduit | 211 | 154 | 97 | 56 | 40 | 25 | 21 | 17 | 13 | 11 | 9 | 7 | 6 | 5 | 4 | 4 | 3 | 3 | 2 | 1 | 1 | |||
| Rigid Conduit | 200 | 146 | 92 | 53 | 38 | 23 | 20 | 17 | 12 | 10 | 8 | 7 | 6 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | |||
| Flexible Metal | 202 | 147 | 93 | 53 | 38 | 20 | 24 | 17 | 12 | 10 | 9 | 7 | 6 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | |||
| 3 | EMT Conduit | 364 | 266 | 167 | 96 | 69 | 43 | 36 | 30 | 22 | 19 | 16 | 13 | 11 | 9 | 7 | 6 | 6 | 5 | 4 | 3 | 3 | ||
| IMC Conduit | 326 | 238 | 150 | 86 | 62 | 38 | 32 | 27 | 20 | 17 | 14 | 12 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 3 | 3 | |||
| Rigid Conduit | 309 | 225 | 142 | 82 | 59 | 36 | 31 | 26 | 19 | 16 | 13 | 11 | 9 | 7 | 6 | 5 | 5 | 4 | 3 | 3 | 3 | |||
| Flexible Metal | 291 | 212 | 134 | 77 | 55 | 34 | 29 | 24 | 18 | 15 | 12 | 10 | 8 | 7 | 6 | 5 | 5 | 4 | 3 | 3 | 2 | |||
| 3 1/2 | EMT Conduit | 476 | 347 | 219 | 126 | 91 | 56 | 47 | 40 | 29 | 25 | 20 | 17 | 14 | 11 | 10 | 9 | 8 | 6 | 5 | 4 | 4 | ||
| IMC Conduit | 326 | 238 | 150 | 86 | 62 | 38 | 32 | 27 | 20 | 17 | 14 | 12 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 3 | 3 | |||
| Rigid Conduit | 309 | 225 | 142 | 82 | 59 | 36 | 31 | 26 | 19 | 16 | 13 | 11 | 9 | 7 | 6 | 5 | 5 | 4 | 3 | 3 | 3 | |||
| Flexible Metal | 291 | 212 | 134 | 77 | 55 | 34 | 29 | 24 | 18 | 15 | 12 | 10 | 8 | 7 | 6 | 5 | 5 | 4 | 3 | 3 | 2 | |||
| 4 | EMT Conduit | 608 | 443 | 279 | 161 | 116 | 71 | 60 | 51 | 37 | 32 | 26 | 22 | 18 | 15 | 13 | 11 | 10 | 8 | 7 | 6 | 5 | ||
| IMC Conduit | 562 | 410 | 258 | 149 | 107 | 66 | 56 | 47 | 35 | 29 | 24 | 20 | 17 | 13 | 12 | 10 | 9 | 7 | 6 | 5 | 5 | |||
| Rigid Conduit | 531 | 387 | 244 | 140 | 101 | 62 | 53 | 44 | 33 | 27 | 23 | 19 | 16 | 13 | 11 | 10 | 8 | 7 | 6 | 5 | 5 | |||
| Flexible Metal | 518 | 378 | 238 | 137 | 99 | 61 | 51 | 43 | 32 | 27 | 22 | 18 | 15 | 12 | 11 | 9 | 8 | 7 | 5 | 5 | 4 | |||
WARNING
Follow the conduit fill capacity guidelines diligently. Overloading the conduit with excessive wires can generate heat, potentially leading to the melting of the vinyl insulation on the wires and posing a fire hazard.
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What are EMT Conduits?
EMT conduits, or Electrical Metallic Tubing, protect and route electrical wiring in various settings. They are made of lightweight steel or aluminum, offering durability and cost-effectiveness.
These conduits are known for easy installation, with flexibility for bending and shaping on-site. Their thin walls and smooth interiors make wire pulling easier, reducing the risk of damage during installation. These conduits are secured with compression or set-screw connectors.
However, EMT conduits are best suited for dry locations and lack corrosion resistance. Consider alternatives like PVC-coated or rigid metal conduits in wet or corrosive environments. Always follow the National Electrical Code (NEC) and local codes for safe and compliant installation.
What are IMC Conduits?
Intermediate Metal Conduit (IMC) is a robust circular steel conduit with a dual-layered defense. Its exterior wears a protective coat of hot galvanized armor, while an interior layer boasts a specialized corrosion-resistant shield. This dynamic combination shields and guides conductors and cables and doubles as an integral equipment grounding conductor when paired with the right fittings.
When it comes to IMC, you'll find various sizes, ranging from 1/2 inch to 4 inches in diameter. IMC is available in 10-foot lengths, and you can choose between threaded or unthreaded ends.
IMC adheres strictly to the safety standards set by UL under standard 1242 and ANSI C80.6. The National Electrical Code (NEC) dedicates Article 342 to provide a compass for IMC's proper and secure utilization in electrical installations.
What is a RIGID Conduit?
Rigid Metal Conduit (RMC) is a hardy, threaded tubing with substantial thickness. It's typically crafted from coated steel, stainless steel, or aluminum. RMC is a circular cross-sectioned raceway that safeguards and guides conductors and cables. It’s also an equipment grounding conductor with integral or associated coupling and appropriate fittings.
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What is Flexible Metal Conduit?
Flexible Metal Conduit (FMC) boasts a spiral design that allows it to navigate through walls and various structures, making it a versatile choice for safeguarding electrical wiring in commercial and industrial buildings.
On the other hand, Liquidight Flexible Metal Conduit (LFMC), a unique variant of FMC, features a protective plastic coating. When paired with sealed fittings, it transforms into a watertight conduit solution, adding an extra layer of protection.
Global Metal Electrical Conduit Market Trends 2023
The global Metal Electrical Conduit market is expected to exceed USD 5.5 billion by 2032, according to a Global Market Insights Inc. research study. This growth is due to a growing demand for secure electrical wiring systems.
Recent advancements in conduit manufacturing, including corrosion-resistant coatings and lightweight designs, have contributed to this trend. Strict safety standards and regulations have also boosted demand for metal electrical conduits.
Notably, the growing application of metal electrical conduits in rail infrastructure, compliance with safety regulations in the commercial sector, and the increasing construction activities in North America are key drivers of this market's growth.
Conduit Fill Charts: Key Takeaways and Final Remarks
At the core of successful electrical work is the precise selection of conduit sizes, and our expertise as a top distributor shines in this regard. We take pride in offering professionals the tools they need, with a focus on Greenlee electrician tools, renowned for quality and reliability.
Greenlee's conduit bending tools, in particular, enhance efficiency and precision on the job. As your trusted source for Greenlee tools, we're here to ensure your projects have the best tools and expertise in the industry.
Read about our Top Seven Greenlee Benders if you’re still on the fence about what conduit bender you should buy.
Conduit Fill Chart: Frequently Asked Questions
Are Conduit Fill Charts Standardized?
Yes, they are typically based on industry standards and guidelines. However, local codes may have variations, so it's essential to consult the chart and local regulations.
Is Conduit Required for All Electrical Wiring?
Conduit is not always mandatory, but it is recommended for protecting wires and cables in certain environments or when local codes require it.
What's the Difference Between Rigid Conduit and Electrical Metallic Tubing (EMT)?
Rigid conduit is thicker and more durable, while EMT is thinner and more flexible. EMT is often used where flexibility and ease of installation are required.
What are the NEC guidelines for conduit fill?
According to NEC regulations, the conduit fill chart provides the following maximum fill percentages: For a single conductor, it's 53% of the conduit space. If there are two conductors, the maximum fill is 31%. The maximum fill allowed is 40% of the conduit's capacity when dealing with more than two conductors.
What is the required spacing for conduits?
To ensure proper spacing, maintain a minimum distance of 3 inches between conduits. Use conduit chairs every 4 feet to maintain this spacing, ensuring that the conduit chair system does not create a shear point on the conduit.