Common Cable Types Used in the United States

The United States has a broad array of cable types designed to meet the needs of residential, commercial, industrial, and specialty applications. These cables are manufactured to conform to strict guidelines set forth by organizations such as the National Electrical Code (NEC), Underwriters Laboratories (UL), and the Institute of Electrical and Electronics Engineers (IEEE). Below is an in-depth exploration of the most widely used cable types in the U.S., their specifications, applications, and unique features.

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1. THHN/THWN (Thermoplastic High Heat Nylon-Coated Wire)

Description:
THHN is one of the most widely used wire types in the U.S. It features a thermoplastic insulation with a nylon outer jacket and is rated for high temperatures. THWN is a similar variant that adds water resistance.

Applications:

- Used in residential and commercial wiring systems.
- Common for conduit installations.
- Power distribution in low-voltage applications (up to 600 volts).

Features:

- Heat-resistant up to 90°C in dry locations.
- Nylon outer jacket provides abrasion resistance.
- Available in single conductors.
- Often used with conduit to meet NEC standards.

Standards:

- Compliant with NEC Article 310.
- UL Standard 83.

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2. NM-B (Non-Metallic Sheathed Cable)

Description:
NM-B cables, commonly referred to as "Romex," are used in residential applications for interior wiring. These cables consist of two or more insulated conductors encased in a plastic jacket.

Applications:

- Residential wiring for lights, outlets, and appliances.
- Installation within walls, ceilings, and floors.

Features:

- Typically rated for 600 volts.
- Easy to strip and install.
- Not suitable for outdoor or wet locations.

Standards:

- NEC Article 334.
- UL Standard 719.

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3. MC (Metal Clad Cable)

Description:
MC cables have a metal sheath, typically aluminum or steel, that provides mechanical protection. These cables are preferred for commercial and industrial environments where durability is critical.

Applications:

- Power distribution in industrial facilities.
- Wiring in commercial buildings.
- Indoor installations in exposed or concealed locations.

Features:

- Fire-resistant and durable.
- Can be installed without conduit in some cases.
- Provides electromagnetic interference (EMI) shielding.

Standards:

- NEC Article 330.
- UL Standard 1569.

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4. XHHW (Cross-Linked Polyethylene High Heat Water-Resistant Wire)

Description:
XHHW wire features cross-linked polyethylene insulation, which provides superior heat and water resistance compared to THHN wires.

Applications:

- Underground service entrances.
- Power distribution in industrial and commercial buildings.
- Wet or damp locations.

Features:

- Rated for up to 90°C in wet or dry environments.
- Higher insulation durability.
- Can be installed in conduit for added protection.

Standards:

- NEC Article 310.
- UL Standard 44.

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5. SOOW (Service Oil-Resistant Wire)

Description:
SOOW cables are flexible, portable power cables with resistance to oil, water, and weather conditions.

Applications:

- Portable equipment and tools.
- Temporary power installations.
- Industrial equipment connections.

Features:

- Rubber insulation for flexibility.
- Resistant to oil, chemicals, and UV.
- Available in various conductor sizes.

Standards:

- NEC Article 400.
- UL Standard 62.

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6. Tray Cables (TC)

Description:
Tray cables are versatile cables used in cable trays, raceways, and conduit systems. They are often used in industrial environments.

Applications:

- Power and control circuits.
- Industrial manufacturing facilities.
- Process control and automation systems.

Features:

- Flame retardant and oil resistant.
- Available in shielded and unshielded versions.
- Multi-conductor options for complex installations.

Standards:

- NEC Article 336.
- UL Standard 1277.

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7. URD (Underground Residential Distribution Cable)

Description:
URD cables are designed for underground service entrance installations and are suitable for direct burial.

Applications:

- Underground power distribution to homes and buildings.
- Utility company wiring systems.

Features:

- Weather-resistant polyethylene insulation.
- Available in multi-conductor configurations.
- Rated for high voltages (up to 15 kV in some cases).

Standards:

- NEC Article 310.
- UL Standard 854.

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8. Coaxial Cables

Description:
Coaxial cables are widely used for signal transmission, including television and internet services.

Applications:

- Cable TV and satellite connections.
- Broadband internet.
- Closed-circuit television (CCTV) systems.

Features:

- Shielded to reduce interference.
- High-frequency signal transmission.
- Durable and weather-resistant versions available for outdoor use.

Standards:

- ANSI/SCTE Standards.
- UL Standard 444.

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9. Fiber Optic Cables

Description:
Fiber optic cables transmit data as light signals, providing high-speed and high-capacity communication capabilities.

Applications:

- Internet and telecommunication networks.
- Medical imaging and equipment.
- Data centers.

Features:

- Immune to electromagnetic interference.
- High bandwidth and speed.
- Can cover long distances without signal loss.

Standards:

- ANSI/TIA-568.
- NEC Article 770.

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10. Plenum-Rated Cables (CMP)

Description:
Plenum cables are designed for use in plenum spaces (air-handling spaces in buildings) and are required to meet strict fire safety standards.

Applications:

- Data and communication cabling in commercial buildings.
- HVAC systems and ceiling spaces.

Features:

- Flame-retardant and low-smoke characteristics.
- Suitable for high-density installations.
- Compliant with NEC requirements for plenum spaces.

Standards:

- NEC Article 800.
- UL Standard 910.

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11. Welding Cables

Description:
Welding cables are robust and flexible cables designed to carry high currents needed for welding applications.

Applications:

- Welding equipment.
- Power supply to industrial machines.

Features:

- Rubber insulation for flexibility and durability.
- Designed to handle high temperatures.
- Resistant to oil, flame, and abrasion.

Standards:

- NEC Article 630.
- UL Standard 527.

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12. High-Voltage Cables

Description:
High-voltage cables are used to transmit electricity over long distances and are rated for voltages above 1,000 volts.

Applications:

- Utility transmission lines.
- Large-scale industrial power distribution.

Features:

- Typically shielded for safety.
- Insulated with cross-linked polyethylene or ethylene propylene rubber.

Standards:

- NEC Article 490.
- UL Standard 1072.

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Conclusion

The cable industry in the United States supports a wide range of applications, each with specific requirements and standards. Whether for residential wiring, industrial installations, or advanced communication networks, there is a cable type that meets the necessary safety, performance, and durability criteria. Standards such as UL, NEC, and IEEE ensure these cables are manufactured to the highest quality and reliability.