Southwire NM-B 250 ft Buying Guide: All Sizes 2026 Reference
Southwire NM-B 250 ft Buying Guide: All Sizes 2026 Reference
🕑 12 min read Updated: June 2026 Table of Contents Fast Answer What Is Southwire NM-B in 250 ft Reels? Available Sizes in 250 ft Configuration Gauge Selector...
- These reels are available in common residential branch circuit sizes including 14/2, 14/3, 12/2, 12/3, 10/2, 10/3, 8/2, and 8/3 with ground, covering the full range of typical home circuit applications from 15 amp lighting circuits through 40 amp appliance circuits with the 250 ft reel length providing enough material for whole-circuit installations or meaningful multi-circuit portions of larger projects.
- Gauge selection depends on the circuit amperage and application: 14/2 for 15 amp lighting and general receptacle circuits, 12/2 for 20 amp general purpose and kitchen circuits, 10/2 for 30 amp water heater and dryer circuits, and 8/3 for 40 amp electric range circuits, with corresponding /3 configurations for 3-way switches, multi-wire branch circuits, and appliances requiring neutral.
- These reels are available in both standard and SIMpull versions with identical electrical performance and NEC compliance, with SIMpull adding a reduced-friction jacket at 10 to 25 percent material premium that provides labor time savings for difficult installations while standard Southwire NM-B provides better economic value for easy pulls and DIY installations.
- The 250 ft reel length is the popular middle-ground purchase quantity because it provides enough material for whole-circuit installations, offers better per-foot pricing than 100 ft rolls, and remains manageable for vehicle transport and workspace storage without requiring the bulk handling of 500 ft or 1000 ft reels typically used for larger commercial projects.
- All these reels are Type NM-B per NEC 334 with 60 degree Celsius ampacity limitation per NEC 334.80, restricted to indoor dry locations per NEC 334.12, and include a bare copper equipment grounding conductor as part of the cable assembly for proper equipment grounding per NEC 250.
- The interactive gauge selector tool below evaluates your circuit application, amperage requirement, and standard versus SIMpull preference to recommend the specific 250 ft reel product for your installation with rationale explaining the recommendation based on NEC ampacity requirements and typical residential branch circuit sizing.
The 250 ft reel length in Southwire NM-B is the popular middle-ground for residential branch circuit installations, available in common sizes from 14/2 through 8/3 with ground covering the full range of typical home circuit applications. This buying guide covers the complete product selection process for the reels including available sizes, application-specific gauge selection, the standard versus SIMpull decision, NEC compliance requirements, and practical considerations for storage, handling, and ordering. Use the interactive gauge selector tool to identify the specific product that matches your installation requirements.
Across thousands of Southwire orders shipped from IB Lighting nationwide, our electrician-led team helps buyers select the appropriate product for their specific installation requirements. Founded in 2013 by a licensed Master Electrician with field experience across DTE Energy and Consumers Energy projects in Michigan, IB Lighting is an independent reseller of the complete Southwire electrical wire and cable lineup including all common NM-B sizes in 250 ft reel format for both standard and SIMpull product versions.
This buying guide covers the complete product selection process using citations from the current National Electrical Code (NFPA 70) for NM-B installation requirements per NEC 334.
The Fast Answer: Southwire NM-B 250 ft Buying Guide
Southwire NM-B 250 ft product selection depends on matching the wire gauge to the circuit application and amperage requirement. The 250 ft reel length works well for whole-circuit installations, multi-circuit portions of larger projects, and general residential branch circuit work where the material quantity provides good coverage without excessive storage requirements.
Common gauge quick reference
For most residential applications, the Southwire NM-B 250 ft Product selection follows standard branch circuit sizing: 14/2 with ground for 15 amp lighting and general receptacle circuits, 12/2 with ground for 20 amp general purpose and kitchen small appliance circuits, 10/2 with ground for 30 amp water heater and dryer circuits, and 8/3 with ground for 40 amp electric range circuits. The corresponding /3 versions add a neutral conductor for three-way switches and appliances requiring separate neutral.
Standard vs SIMpull
These reels come in both standard and SIMpull versions with identical electrical performance. Choose standard for DIY installations, new construction with open framing, and cost-focused projects. Choose SIMpull for professional installations with long or difficult pulls where reduced pulling friction provides labor time savings that justify the 10 to 25 percent material premium.
NEC compliance basics
All these reels are Type NM-B per NEC 334 and are restricted to indoor dry locations per NEC 334.12. The 60 degree Celsius ampacity limitation per NEC 334.80 applies to all sizes. For applications outside these restrictions (outdoor, direct burial, wet locations), use appropriate alternative cable types like UF-B for direct burial or individual THHN conductors in PVC conduit.
What Is Southwire NM-B in 250 ft Reels?
Understanding what Southwire NM-B in 250 ft reels actually is provides the foundation for informed product selection.
NM-B cable definition
NM-B (Non-Metallic Sheathed Cable, Type B) is the standard cable type for residential indoor branch circuits in the United States. The cable consists of individual insulated copper conductors bundled together and encased in a solid outer PVC jacket. NM-B is manufactured to Underwriters Laboratories (UL) 719 standards and is covered by NEC 334.
Southwire manufacturing background
Southwire is one of the largest electrical wire and cable manufacturers in North America, based in Carrollton, Georgia. Southwire manufactures NM-B under the Romex brand name (a trademark acquired through the General Cable acquisition in 2018) and other product designations. All Southwire NM-B products meet UL and NEC requirements for Type NM-B cable.
250 ft reel format
The Southwire NM-B 250 ft reel format packages the cable on a spool for convenient dispensing during installation. The 250 ft length represents a popular middle-ground quantity between smaller 100 ft rolls (used for very small projects) and larger 500 ft or 1000 ft reels (used for large residential or commercial projects). The reel provides physical protection during shipping and organized dispensing during use.
Cable construction
The reels contain cable with individual insulated copper conductors color-coded by function (black for hot, white for neutral, red for second hot in /3 configurations) plus a bare copper equipment grounding conductor. The conductors are bundled together with paper filler and encased in the outer PVC jacket. The construction meets all UL 719 and NEC 334 requirements.
Available Sizes in 250 ft Configuration
The Southwire NM-B 250 ft reel format is available in common residential branch circuit sizes, each matching specific circuit amperage requirements.
14 AWG configurations (15 amp circuits)
Southwire NM-B 14/2 with ground in 250 ft reels covers 15 amp branch circuits for lighting and general receptacles. The 14/3 with ground reel adds a red conductor for three-way switch installations and split receptacle applications. Both configurations use 14 AWG copper conductors with the 15 amp ampacity limit per NEC 334.80 and NEC 240.4(D).
12 AWG configurations (20 amp circuits)
Southwire NM-B 12/2 in 250 ft reels covers 20 amp branch circuits for general purpose receptacles, bathroom circuits, and kitchen small appliance circuits. The 12/3 with ground reel adds a red conductor for three-way switches, multi-wire branch circuits, and split-receptacle installations. Both use 12 AWG copper with the 20 amp ampacity limit per NEC 240.4(D).
10 AWG configurations (30 amp circuits)
Southwire NM-B 10/2 in 250 ft reels covers 30 amp dedicated circuits including water heaters, some dryer installations, and small appliance circuits. The 10/3 with ground reel adds a red conductor for standard 30 amp electric dryer circuits requiring separate neutral. Both use 10 AWG copper conductors.
8 AWG configurations (40 amp circuits)
The 8/2 with ground reel covers 40 amp circuits for some water heater and appliance installations. Southwire NM-B 8/3 with ground in 250 ft reels adds a red conductor for 40 amp electric range circuits and other appliances requiring separate neutral. Both use 8 AWG copper conductors.
Which Size for Which Application
Matching the product to specific applications ensures proper circuit sizing and NEC compliance.
14/2 with ground applications
Southwire NM-B 14/2 with ground in 250 ft reels covers 15 amp branch circuits including bedroom and living area lighting circuits, general receptacle circuits in bedrooms and living areas, hallway lighting, and closet lighting. The 15 amp ampacity limit per NEC 240.4(D) small conductor rule restricts 14 AWG to 15 amp maximum overcurrent protection.
14/3 with ground applications
The 14/3 with ground reel covers 15 amp circuits requiring the extra conductor including three-way switch installations, split receptacle configurations, switched receptacle wiring, and multi-wire branch circuits for 15 amp applications. The additional red conductor provides the traveler wire between three-way switches.
12/2 with ground applications
Southwire NM-B 12/2 with ground in 250 ft reels covers 20 amp branch circuits including general purpose receptacle circuits in kitchens and bathrooms, kitchen small appliance circuits (per NEC 210.11 requirements), bathroom circuits, laundry circuits, and garage receptacle circuits. The 20 amp ampacity limit per NEC 240.4(D) applies to 12 AWG conductors.
12/3 with ground applications
The 12/3 with ground reel covers 20 amp circuits requiring the extra conductor including three-way switch installations for 20 amp circuits, multi-wire branch circuits for 20 amp applications, and split-receptacle configurations. Multi-wire branch circuits share a neutral between two 120V hot conductors on opposite phases.
10/2 with ground applications
The 10/2 with ground reel covers 30 amp dedicated circuits without neutral requirement including electric water heaters (typically 240V only), some 30 amp appliance circuits, and 30 amp air conditioning circuits (for units under 30 amp continuous load). Water heaters are the most common 10/2 application in residential installations.
10/3 with ground applications
The 10/3 with ground reel covers 30 amp circuits requiring separate neutral including standard 30 amp electric dryer circuits, some 30 amp appliance circuits requiring 120V control components, and legacy applications requiring 4-wire circuits. Electric dryers are the most common 10/3 application.
8/2 with ground applications
The 8/2 with ground reel covers 40 amp circuits without neutral requirement including some water heater installations, larger appliance circuits, and specific commercial applications. The 40 amp ampacity per NEC 334.80 60 degree column applies to 8 AWG NM-B.
8/3 with ground applications
The 8/3 with ground reel covers 40 amp circuits requiring separate neutral including standard 40 amp electric range circuits, larger 40 amp appliance circuits with 120V control components, and some HVAC circuits. Electric ranges are the most common 8/3 application in residential installations.
Why 250 ft Is the Popular Reel Length
The Southwire NM-B 250 ft reel length has become the popular middle-ground purchase quantity for several practical reasons that make it work well for typical residential installations.
Coverage for whole-circuit installations
A Southwire NM-B 250 ft reel provides enough material for most whole-circuit installations without requiring multiple purchases. A typical residential branch circuit runs 40 to 100 feet from the panel to the last device, meaning a 250 ft reel covers 2 to 6 typical circuits depending on runs. This coverage matches how residential electrical projects are typically scoped.
Better per-foot pricing than smaller rolls
The 250 ft reel typically offers better per-foot pricing than 25 ft, 50 ft, or 100 ft roll sizes. Manufacturers offer volume pricing that scales with reel size, and the 250 ft length hits a meaningful volume threshold. Buyers get material cost efficiency without the storage requirements of larger reels.
Manageable storage and transport
The 250 ft reel format is manageable for typical residential storage and transport. The reel fits in a typical vehicle trunk, moves easily through doorways, and stores in workshop or garage spaces without requiring dedicated storage rooms. Larger 500 ft and 1000 ft reels present more challenging handling for smaller projects.
Suits multi-circuit projects
The 250 ft reel length suits multi-circuit residential projects like whole-room electrical work, small addition wiring, or several new circuits added to an existing home. This scope matches many typical residential electrical projects where buyers need meaningful coverage but not commercial-scale material quantities.
Standard vs SIMpull in 250 ft Reels
Southwire NM-B 250 ft is available in both standard and SIMpull versions, with each providing specific advantages for different installation types.
Same electrical performance
Standard Southwire NM-B and SIMpull NM-B have identical electrical performance including same copper conductor material, same insulation ratings, same ampacity per NEC 334.80, same voltage ratings, and same NEC compliance. Both are Type NM-B per NEC 334 with identical installation restrictions per NEC 334.12. Both use the same standard cable clamps, connectors, and installation hardware.
The jacket technology difference
The only functional difference is the outer jacket technology. Standard Southwire NM-B uses traditional PVC jacket construction. SIMpull uses Southwire proprietary reduced-friction jacket technology designed to reduce pulling force during installation per Southwire product literature. The internal cable construction is identical between the two versions.
Cost premium for SIMpull
SIMpull typically adds a 10 to 25 percent material premium per foot compared to standard Southwire NM-B in equivalent sizes. On a 250 ft reel, this premium translates to a meaningful absolute dollar difference. Whether the premium is worthwhile depends on installation type and whether the reduced friction provides labor time savings that offset the material cost.
When to choose each version
Choose the standard version for DIY installations, new construction with open framing before drywall, small projects with short pulls, and cost-focused installations. Choose the SIMpull version for professional installations with long or difficult pulls, retrofit installations through existing walls, bundled cable pulls of multiple cables, and installations where reduced installer fatigue provides value. See our detailed Southwire SIMpull vs standard Romex comparison for the complete decision framework.
NEC Compliance for Southwire NM-B
All Southwire NM-B products are subject to identical NEC compliance requirements regardless of size or standard versus SIMpull version.
NEC 334 governance
NEC 334 covers Non-Metallic Sheathed Cable Types NM, NM-B, and NM-C. Southwire NM-B falls under Type NM-B classification with the specific requirements defined in NEC 334.10 (uses permitted), NEC 334.12 (uses not permitted), NEC 334.15 (installation methods), NEC 334.30 (securing and supporting), and NEC 334.80 (ampacity).
NEC 334.80 ampacity limitation
NEC 334.80 requires NM-B ampacity to be determined using the 60 degree Celsius column of NEC Table 310.16 regardless of individual conductor insulation rating. This restriction results in the following ampacity: 14 AWG at 15 amp, 12 AWG at 20 amp, 10 AWG at 30 amp, 8 AWG at 40 amp. These limits apply to all Southwire NM-B products.
NEC 334.10 permitted uses
NEC 334.10 permits NM-B use in one and two-family dwellings, multi-family dwellings not exceeding three stories above grade, and other specified structures. NM-B is primarily used for concealed installations within wall, floor, and ceiling cavities. The product is appropriate for all permitted NEC 334.10 applications.
NEC 334.12 prohibited uses
NEC 334.12 prohibits NM-B in specific applications including exposed installations subject to physical damage (unless protected), wet locations, direct burial applications, embedded in poured concrete, and other specified restrictions. For applications outside NEC 334.10 permitted uses, alternative cable types like UF-B or individual conductors in conduit are required.
Product Specifications and Construction
Southwire NM-B 250 ft product specifications match NEC and UL requirements for Type NM-B cable across all sizes.
Conductor material
Southwire NM-B conductors in typical residential sizes (14 AWG through 6 AWG) are solid copper for smaller sizes and stranded copper for larger sizes. The solid vs stranded transition typically occurs at 8 AWG, though specific product configurations may vary. Copper provides the standard conductor material for residential NM-B applications.
Insulation and jacket
Individual conductor insulation on Southwire NM-B is PVC-based thermoplastic rated for 60 degree Celsius operation (though the NEC 334.80 ampacity limit prevents utilizing higher temperature ratings even if the insulation itself supports them). The outer jacket is PVC-based on standard products or SIMpull reduced-friction formulation on SIMpull products.
Color coding
Standard Southwire NM-B color coding follows industry convention with black insulation for hot conductor(s), white insulation for neutral, red insulation for second hot in /3 configurations, and bare copper for the equipment grounding conductor. The specific colors may vary between manufacturers but Southwire uses standard residential color coding.
UL listings
Southwire NM-B products carry UL listing to UL 719 standards for Non-Metallic Sheathed Cable. The UL listing verifies compliance with construction requirements, dimensional requirements, electrical performance requirements, and safety requirements. The UL mark appears on the cable jacket at regular intervals along the length.
Storage and Handling
Proper storage and handling of the reels preserves the cable condition and simplifies installation.
Reel storage orientation
Store the reels flat on the ground with the reel axis vertical, or upright with the axis horizontal supported to prevent flat spots on the cable. Avoid stacking heavy items on reels which can deform the cable geometry. Original packaging protects the cable during transport and storage.
Temperature considerations
Store cable in dry conditions at moderate temperatures. Extreme heat can accelerate jacket degradation over long storage periods. Extreme cold makes the cable stiffer and more difficult to install. Temperature-controlled storage extends useful life for cable that will not be installed immediately.
Physical protection during transport
Southwire NM-B is durable but not indestructible. Protect reels from sharp objects that could pierce the jacket, from being run over by vehicles, and from being dropped from height. Damaged cable should be inspected before installation and rejected if the damage extends to individual conductor insulation.
Dispensing during installation
Use a cable dispensing reel or two-person hand dispensing to feed cable during installation. Attempting to pull cable off a stationary reel can twist the cable and cause installation problems. Proper dispensing preserves the cable geometry and simplifies threading through joists and studs during installation.
How Much Coverage 250 ft Provides
Understanding coverage helps determine whether 250 ft is the right reel length for your specific installation.
Typical branch circuit run length
Typical residential branch circuit runs range from 40 to 100 feet from the electrical panel to the last device on the circuit. Short circuits (bathroom exhaust fan, single receptacle addition) may be under 25 feet. Long circuits (whole-room receptacle circuit, distant appliance) may exceed 75 feet. A 250 ft reel typically covers 2 to 6 circuits depending on run length.
Small addition project coverage
For small addition projects like a home office, small bedroom, or bathroom renovation, a 250 ft reel typically provides more than enough coverage for the circuit needs. Common project types requiring 250 ft or less include single-room electrical upgrades, small kitchen additions, garage electrical work, and dedicated appliance circuits.
Multi-room project coverage
For multi-room projects like whole-floor renovations or major additions, buyers may need multiple 250 ft reels or should consider 500 ft reels for cost efficiency. Calculating actual footage needs helps determine whether 250 ft is adequate or whether larger quantities are more economical for the specific project.
Waste factor consideration
Add approximately 10 to 20 percent to calculated footage requirements to account for waste, connection allowances, and unexpected routing changes. A project requiring 200 feet of calculated cable should purchase at least 220-240 feet, making the 250 ft reel appropriate. Larger projects may benefit from multiple reels or single larger reels.
Ordering Considerations
Practical ordering considerations help ensure the right products arrive for your installation timeline.
Verify size and configuration before ordering
Verify the required Southwire NM-B 250 ft size before ordering. Match the wire gauge to the circuit amperage per NEC 240.4(D) and NEC 334.80 requirements. Verify whether the application requires /2 (no separate neutral) or /3 (separate neutral required) configuration. Wrong size selection requires reordering and installation delays.
Standard vs SIMpull decision before ordering
Decide whether standard or SIMpull is appropriate before ordering. The SIMpull premium is committed at purchase. If installation type matches the SIMpull value proposition (long pulls, retrofit work, bundled cables, professional installations), order SIMpull. If installation is simple or DIY, order standard version for better economics.
Shipping considerations
These reels are moderately heavy but manageable for standard shipping. IB Lighting ships nationwide with free freight insurance included on Southwire products. Verify delivery timing before starting installation work to ensure materials arrive when needed. Contact (800) 674-9019 with questions about specific product availability and shipping timing.
Quantity planning for larger projects
For projects requiring more than 250 ft of a specific size, evaluate whether multiple 250 ft reels or single larger 500 ft or 1000 ft reels provide better economics. Larger reels typically offer better per-foot pricing but require different handling and storage. Current pricing on specific reel sizes is shown on individual product pages.
5 Common Mistakes Buying Southwire NM-B 250 ft
The mistakes below cause the most frequent problems for buyers evaluating Southwire NM-B 250 ft options when buyers purchase these reels without complete understanding.
Mistake 1: Buying wrong gauge for circuit amperage
The most common mistake is buying wrong gauge for the intended circuit amperage. Southwire NM-B 14/2 250 ft cannot be used on 20 amp circuits (NEC 240.4(D) limits 14 AWG to 15 amp). Southwire NM-B 12/2 250 ft cannot be used on 30 amp circuits. Match the gauge to the intended amperage before purchase, using the NEC 334.80 60 degree column ampacity: 15 amp for 14 AWG, 20 amp for 12 AWG, 30 amp for 10 AWG, 40 amp for 8 AWG.
Mistake 2: Buying /2 when /3 is required
Some buyers purchase /2 configuration when their application requires /3. Electric dryers require 10/3 for the standard 4-wire dryer receptacle. Electric ranges require 8/3 for the standard 4-wire range receptacle. Three-way switches require /3 for the traveler conductor. Verify neutral requirement before ordering to avoid needing to reorder the /3 version.
Mistake 3: Buying SIMpull for simple DIY projects
Some DIY buyers purchase SIMpull thinking it provides better electrical performance. It does not. SIMpull only reduces pulling friction, which provides minimal value for simple DIY installations. The material premium is essentially wasted on installations where the standard version would perform equivalently. Reserve SIMpull for installations that actually benefit from reduced friction.
Mistake 4: Buying 250 ft when a different length is more economical
Some buyers default to 250 ft without evaluating whether a different reel size provides better economics. Small projects requiring under 100 ft may be better served by 100 ft rolls. Large projects requiring over 400 ft may be better served by 500 ft reels for better per-foot pricing. Match reel size to actual project requirements including 10-20 percent waste factor.
Mistake 5: Not verifying indoor dry location requirement
Some buyers purchase NM-B for applications where the product cannot be used. NM-B is restricted to indoor dry locations per NEC 334.12. For outdoor applications, use UF-B cable. For wet locations, use individual THWN-2 conductors in PVC conduit. For direct burial, use UF-B or individual conductors in appropriate conduit. Verify the installation application matches NM-B permitted uses before ordering.
Ready to order Southwire NM-B for your installation?
IB Lighting is an independent reseller of Southwire electrical wire and cable including all common Southwire NM-B 250 ft options for both standard and SIMpull versions. Call (800) 674-9019 or browse Southwire NM-B products.
Frequently Asked Questions
What sizes are available?
Southwire NM-B 250 ft reels are available in common residential branch circuit sizes including 14/2, 14/3, 12/2, 12/3, 10/2, 10/3, 8/2, and 8/3 with ground. Each size matches specific circuit amperage requirements per NEC 240.4(D) and NEC 334.80. Available in both standard and SIMpull versions. Specific stocked sizes and current availability shown on individual product pages.
Which size do I need for a 20 amp circuit?
For a 20 amp branch circuit, use 12/2 with ground (or 12/3 if a separate neutral is required for three-way switches or multi-wire branch circuits). The 12 AWG copper conductor size provides the required 20 amp ampacity per NEC 334.80 60 degree column and NEC 240.4(D) small conductor rule.
Can these reels be used outdoors or underground?
No. The cable is restricted to indoor dry locations per NEC 334.12 regardless of size or reel length. Outdoor applications require UF-B cable rated for wet and outdoor use. Direct burial applications require UF-B or individual THWN-2 conductors in appropriate conduit. See our direct burial wire depth requirements guide for underground installation guidance.
How many circuits will a 250 ft reel cover?
A 250 ft reel typically covers 2 to 6 typical residential branch circuits depending on run length. Short circuits (25 to 50 feet each) allow 5 to 10 circuits per reel. Long circuits (75 to 100 feet each) allow 2 to 3 circuits per reel. Add 10 to 20 percent waste factor to actual footage requirements when planning.
Is this the same as Romex 250 ft?
Yes, effectively. Romex is the trademark brand name Southwire uses for their NM-B cable line (Romex was originally a General Cable brand, acquired by Southwire in 2018). The two designations refer to the same product depending on specific marketing designation. Both are Type NM-B per NEC 334.
Should I buy standard or SIMpull version in 250 ft reels?
Choose the standard version for DIY installations, new construction with open framing, short pulls, and cost-focused projects. Choose Southwire SIMpull NM-B 250 ft for professional installations with long or difficult pulls, retrofit work through existing walls, or bundled cable installations where reduced pulling friction saves labor time.
Do the reels include a ground wire?
Yes. All these products include a bare copper equipment grounding conductor as part of the cable assembly. The ground conductor is sized appropriately for the cable ampacity per NEC 250.122 and does not require separate ordering. The bare ground conductor is standard on all NM-B products regardless of size.
Where can I buy this product?
These products are available through electrical resellers nationwide including IB Lighting. Available sizes include 14/2, 14/3, 12/2, 12/3, 10/2, 10/3, 8/2, and 8/3 with ground in both standard and SIMpull versions. Contact IB Lighting at (800) 674-9019 or through the electrical wire and cable collection.
Conclusion
The 250 ft reel length is the popular middle-ground for residential branch circuit installations for residential branch circuit installations, available in common sizes from 14/2 through 8/3 with ground covering the full range of typical home circuit applications. Selecting the appropriate product requires matching the wire gauge to the circuit amperage per NEC 334.80 (15 amp for 14 AWG, 20 amp for 12 AWG, 30 amp for 10 AWG, 40 amp for 8 AWG), determining whether /2 or /3 configuration is required based on neutral requirements, and choosing between standard and SIMpull versions based on installation characteristics.
Use standard NM-B for DIY installations, new construction with open framing, and cost-focused projects. Use SIMpull for professional installations with long or difficult pulls where reduced friction provides labor time savings. All these products are Type NM-B per NEC 334 with the same 60 degree Celsius ampacity limitation per NEC 334.80 and same restriction to indoor dry locations per NEC 334.12 regardless of size or product version. Use the interactive gauge selector tool above to identify the specific product for your installation.
Ready to order Southwire NM-B 250 ft for your installation?
IB Lighting resells the complete Southwire NM-B lineup in 250 ft reels nationwide with free freight insurance included. Call (800) 674-9019 or browse Southwire electrical wire products.
This buying guide was last reviewed and updated in June 2026 to reflect current Southwire product availability and National Electrical Code requirements for Type NM-B installations (NEC 334). Southwire, SIMpull, and Romex are registered trademarks of Southwire Company LLC. IB Lighting is an independent reseller of Southwire products and does not have a manufacturer sponsorship, dealer authorization, or partnership relationship with Southwire. Product features, pricing, availability, and specific stocked sizes are subject to change and may vary by region. Current specific pricing on these products is shown on individual product pages.