INTERMEDIATE METAL CONDUIT (IMC)
IMC Steel Conduit
Marathon Intermediate Metal Conduit (IMC) is manufactured from high-strength steel to deliver mechanical protection and long-term reliability in electrical raceway systems. Lighter than traditional rigid conduit but built for demanding environments, IMC provides a durable, cost-effective solution for commercial, industrial, and residential applications.
Available in standard trade sizes from ½ inch to 4 inches and a nominal length of 10 feet, each conduit is precisionthreaded on both ends per ANSI/ASME B1.20.1. A threaded coupling is pre-installed on one end; the other is protected with a color-coded thread cap for easy handling and identification.
Features and Benefits
- Lightweight and Durable: Constructed from ductile steel, IMC is up to 30% lighter than standard rigid conduit, reducing strain during transport and installation.
- Cost-Effective Solution: Cuts material and labor costs by up to 30% compared to galvanized rigid conduit, while maintaining code-compliant strength and function.
- Corrosion-Resistant Coating: Hot-dip galvanized exterior protects against corrosion and white rust for reliable performance in indoor and outdoor environments.
- Smooth Interior Finish: Provides a continuous, low-friction raceway that simplifies wire pulling and reduces abrasion.
Certified and Code-Compliant: UL 1242 listed, meets ANSI C80.6 standards, complies with NEC Article 250.118 (3).
- Size Availability: Offered in trade sizes from ½" (16 mm) to 4" (103 mm) for varied installation needs.
Ordering Information
| Part Number | Size (U.S.) | Size (Metric) | Outside Diameter (in.) | Outside Diameter (mm) | Inside Diameter (in.) | Inside Diameter (mm) | Feet Per Bundle | Pieces Per Lift |
| 40156400001 | ½" | 16 | 0.82 | 20.83 | 0.81 | 20.57 | 100 | 35 |
| 40156400002 | ¾" | 21 | 1.03 | 26.26 | 1.02 | 26.01 | 50 | 50 |
| 40156400003 | 1" | 27 | 1.3 | 32.89 | 1.29 | 32.64 | 50 | 34 |
| 40156400004 | 1 ¼" | 35 | 1.65 | 41.78 | 1.63 | 41.4 | | |
| 40156400005 | 1 ½" | 41 | 1.89 | 48.01 | 1.88 | 47.62 | | |
| 40156400006 | 2" | 53 | 2.37 | 60.12 | 2.35 | 59.74 | | |
| 40156400007 | 2 ½" | 63 | 2.87 | 72.82 | 2.85 | 72.31 | | |
| 40156400008 | 3" | 78 | 3.49 | 88.54 | 3.47 | 88.04 | | |
| 40156400009 | 3 ½" | 91 | 3.98 | 101.12 | 3.96 | 100.61 | | |
| 40156400010 | 4" | 103 | 4.48 | 113.69 | 4.46 | 113.18 | | |
* The lengths indicated are designed to produce a 10-foot (3.05-m) length of conduit when a standard coupling is attached.
Tolerance: Thread length: ±1 thread; recommended practice +0, -1; Pitch diameter: +1 turn maximum variation from the gauging face of working thread gauges