12/2 romex 100 ft is a common residential wiring choice for standard 120V circuits in homes and small commercial spaces. This configuration typically uses 12 AWG copper conductors in a non-metallic sheathed cable, protected by a 20 amp breaker.
When planning a project, understanding exact specifications, pricing, and installation best practices helps you buy the right product and avoid rework. The following sections break out key technical data, applications, and real world guidance for 12/2 romex 100 ft runs.
| Specification | Value | Notes |
|---|---|---|
| Cable Type | NM-B Non-Metallic Sheathed Cable | Standard residential wiring rated for dry, protected locations |
| Conductor Size | 12 AWG | Copper conductors for general purpose circuits |
| Conductor Count | 2 Conductors + Ground | Two insulated wires and a bare equipment grounding conductor |
| Length | 100 ft | Single continuous reel for large run jobs |
| Typical Use | 20 Amp Lighting and Outlet Circuits | Pairs with 20 amp breakers in residential panels |
Key Electrical Specifications for 12/2 Romex 100 ft
Conductor Material and Insulation
12/2 romex 100 ft usually contains copper conductors with THHN/THWN style insulation inside a PVC jacket. This design provides moisture resistance and protection against chemical exposure in walls and ceilings.
Ampacity and Derating Factors
At standard ambient temperatures, 12 AWG copper in free air is rated around 20 amps. When bundled in walls or in high temperature environments, local codes may require derating to stay within safe operating limits.
Appropriate Applications and Installation Practices
Residential Lighting and Outlet Circuits
Homeowners and electricians often specify 12/2 romex 100 ft for bedroom lighting, general purpose outlets, and small appliance circuits where a 20 amp load is expected.
Best Practices for Long Runs
For a 100 ft run, plan to minimize sharp bends, maintain proper support spacing, and verify voltage drop, especially on long feeder segments that supply heavy loads.
Pricing, Brands, and Where to Buy
Brand Options and Availability
Major brands like Southwire, Romex, and True offer 12/2 cables in 100 ft lengths at home centers, electrical distributors, and online marketplaces.
Cost Considerations
Pricing varies by retailer, region, and whether you choose a well known brand or a value option. Buying a full 100 ft reel can be more economical than multiple shorter pieces for large jobs.
| Brand | Typical Price for 100 ft | Where to Buy | Warranty or Support |
|---|---|---|---|
| Southwire | Mid range | Home centers, electrical suppliers | Manufacturer limited warranty |
| Romex | Mid to high range | Authorized dealers, online | Brand backed support |
| True | Value pricing | Online and local stores | Standard retail return policy |
| Local Private Label | Budget friendly | Discount builders supply | Store specific guarantees |
Safety, Code Compliance, and Best Practices
Electrical Code Requirements
Local and national codes specify permitted uses, termination methods, and required grounding for 12/2 romex 100 ft installations. Always check with your local authority having jurisdiction.
Protective Devices and Labeling
Use a 20 amp breaker and appropriate box fittings to protect the cable and ensure safe access for future maintenance. Label circuits clearly to help troubleshooting and home inspections.
Planning and Execution Recommendations for 12/2 Romex 100 ft Projects
- Confirm circuit amperage and local code before selecting 12 AWG NM cable.
- Measure the run length and plan the reel placement to minimize sharp bends and excess waste.
- Use proper support spacing and junction boxes for safe, accessible terminations.
- Test voltage at the far end under load to verify performance before finishing walls.
- Document the circuit path and label breakers to simplify future troubleshooting.
FAQ
Reader questions
Can I use 12/2 romex 100 ft for a 240V appliance circuit?
No, 12/2 cable with a ground is typically rated only for 120V circuits. A 240V appliance usually requires 12/3 cable to provide two hot conductors plus neutral and ground.
How many outlets can I put on a 12/2 romex 100 ft circuit limited by a 20 amp breaker?
Follow the 80 percent rule and local code guidance, generally loading the circuit to no more than 16 amps, and installing enough outlets so each does not exceed recommended load per outlet and wire capacity.
Is aluminum wiring ever used in 12/2 romex 100 ft installations?
Aluminum conductors are uncommon in typical NM residential cable, which is predominantly copper, and special rated aluminum cables and compatible devices are required where permitted.
What should I do if the voltage drop is too high on a 100 ft 12/2 romex run?
Check for excessive bends, verify proper wire gauge for the load, consider using a larger conductor size, or shorten the run to reduce voltage drop and keep equipment operating correctly.