Electrical

Electrical Wire Types: Choosing the Right Wire

May 18, 2025

Electrical Team

5 min read

Electrical Wire Types: Choosing the Right Wire

When you look at the wiring in your home, you might see a variety of colors and sheathing types. Each type of electrical wire is designed for a specific purpose, and using the right wire for the job is essential for a safe, code-compliant electrical installation. This guide covers some of the most common types of residential wiring.

🏠 Non-Metallic (NM-B) Cable

Also known by the popular brand name "Romex," this is the most common type of wiring found inside modern homes.

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Description: A flexible cable containing two or more insulated conductors (hot and neutral) and a bare copper ground wire, all wrapped in a plastic outer sheathing.

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Use: For interior use in dry locations only. It's used for nearly all standard circuits, including outlets, switches, and light fixtures.

💧 Underground Feeder (UF-B) Cable

This is the workhorse for outdoor and underground applications.

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Description: Similar to NM-B, but the insulated conductors are individually embedded in solid plastic sheathing, making it highly water-resistant.

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Use: For direct burial underground without conduit. It's used to run power to outdoor lights, detached garages, and sheds.

🔧 THHN/THWN Wire

These are individual, insulated conductors typically used inside conduit.

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Description: Single conductors with thermoplastic insulation. THHN is rated for high heat, and THWN is rated for wet locations. Most modern wire is dual-rated.

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Use: Pulled through conduit (metal or PVC pipe) in unfinished areas like basements, garages, and commercial buildings.

🔢 Understanding Wire Gauge (Size)

The size of the wire, or its gauge, determines how much current it can safely carry. The smaller the gauge number, the thicker the wire.

14-Gauge

Used for 15-amp circuits (e.g., standard lighting and outlets).

12-Gauge

Used for 20-amp circuits (e.g., kitchen outlets, bathrooms, and garages).

10-Gauge

Used for 30-amp circuits (e.g., clothes dryers, some water heaters).

6/8-Gauge

Used for high-power appliances like electric ranges and central air conditioners.

Using a wire that is too small for the amperage of the circuit is a serious fire hazard. Always match the wire gauge to the circuit breaker rating.

Choosing the correct wire type and gauge is a critical safety decision. For any new wiring or circuit installation, trust the professionals at Aircare In A Box to ensure the job is done safely and up to code.