Southwire 250-ft 10 / 3 / Romex SIMpull Solid Indoor CU NM-B W/G Individual pack ( By-the-roll )

The Southwire 10/3 NM-B 250 ft Romex SIMpull is the heavy-gauge residential branch circuit cable for 30-amp 120/240V applications, the wire contractors pull whenever an electric dryer, electric water heater, small air conditioning unit, or similar dual-voltage appliance needs a dedicated circuit. As 10 gauge wire with ground, the Southwire 10/3 NM-B 250 ft includes three insulated 10 AWG solid copper conductors plus a bare copper equipment ground, all enclosed in an orange PVC nylon jacket (orange is the industry-standard Southwire color for 10 AWG NM-B). The 10/3 Romex SIMpull jacket is the SIMpull friction-reducing version of standard NM-B, which cuts pull effort meaningfully compared to legacy Romex and matters especially on 10/3 because the larger gauge cable is heavier and more prone to binding on long pulls. As an NM-B 10/3 cable 250 ft spool, the unit length covers typical residential dryer circuit runs from panel to laundry room with comfortable headroom, plus residential water heater circuits and small AC unit branches. As a 10/3 electric dryer wire, the cable carries both hot conductors (for the 240V heating element) and the neutral (for the 120V controls, motor, and lighting) on the same cable run, which is what modern 4-prong dryer receptacles require. Every Southwire 10/3 NM-B 250 ft spool is UL Listed, made in the USA, and ships nationwide from IB Lighting with free freight and contractor volume pricing. Manufacturer specifications are available at the official Southwire website.

Southwire 10/3 NM-B 250 ft Key Highlights

10/3 Romex SIMpull: Why SIMpull Matters Most on Heavy-Gauge Cable

The defining feature of the Southwire 10/3 NM-B 250 ft Romex SIMpull is the SIMpull jacket itself. Standard NM-B jackets have always been a friction surface, especially when pulled through bored holes in framing studs or stacked through multiple knockouts in a panel. SIMpull is Southwire’s friction-reducing surface treatment that turns a sticky pull into something closer to a pipe slide. Independent contractor testing puts the friction reduction at roughly 50 percent compared to legacy non-SIMpull NM-B, which translates directly into faster rough-in and less crew exhaustion.

The SIMpull advantage matters more on 10/3 than on the smaller 14 or 12 gauge cables because 10/3 is physically larger, heavier, and meaningfully stiffer. Three insulated 10 AWG conductors plus a ground packs significant bulk inside the jacket, which means more friction against framing during pulls and more weight pulling against the installer. Standard 10/3 NM-B on a long run through ceiling joists typically requires two installers: one feeding the cable from the spool, one pulling at the receiver end. SIMpull lets a single installer handle most residential 10/3 runs solo, especially the laundry and utility room runs that consume most 10/3 on residential rough-ins.

10 Gauge Wire with Ground: What It Means

The “10/3 with ground” specification on the Southwire 10/3 NM-B 250 ft tells you everything about the conductor configuration. The “10” is the AWG gauge, which determines the current-carrying capacity of the wire. 10 AWG copper is rated for 30 amps in the National Electrical Code residential branch circuit table, which is the standard service for electric dryers, electric water heaters at 30-amp configurations, and similar dual-voltage appliances. The “3” means three insulated current-carrying conductors. In NM-B 10/3, these are typically a black hot, a red hot, and a white neutral. The “with ground” portion is the bare copper equipment grounding conductor that runs alongside the insulated conductors inside the jacket.

The third conductor matters specifically because the appliances that use 10/3 typically need both 240V (between the two hots) for the heating elements and 120V (between either hot and the neutral) for control electronics, motors, lights, and accessories. Without the neutral conductor, the appliance cannot operate its 120V components. This is why 10/3 with ground is the correct cable for modern electric dryers (which use 4-prong receptacles requiring two hots, a neutral, and a ground), water heaters with electronic controls, and similar appliances. 10/2 with ground is used for appliances that only need 240V without the 120V reference, which is a smaller category of installations.

Common Applications for the Southwire 10/3 NM-B 250 ft

The Southwire 10/3 NM-B 250 ft Romex SIMpull is the dedicated cable for 30-amp 120/240V residential appliance branches. The most common applications include:

• Electric clothes dryer branches. Modern 4-prong dryer receptacles require two hots, a neutral, and a ground, which 10/3 supplies in a single cable run.
• Electric water heaters at 30-amp configurations. Some larger residential electric water heaters use 30-amp 120/240V service.
• Small residential air conditioning units. Window AC units and small mini-split systems often need 30-amp 120/240V service.
• Hot tubs and spas at 30-amp configurations. Smaller residential hot tubs that fall within the 30-amp service limit.
• Some electric range hood and double oven branches. Specific appliances where dual-voltage service is required at 30 amps.
• Workshop and garage heavy equipment branches. Welders, air compressors, and similar 30-amp 120/240V tools.
• Sub-panel feeders at the 30-amp limit. Smaller detached structure sub-panel feeds where 30 amps is sufficient capacity.

For appliances needing 30-amp 240V only (without the 120V neutral reference), the Southwire 10/2 NM-B is the correct cable choice. For 20-amp 120/240V circuits, the Southwire 12/3 NM-B Romex SIMpull 250 ft is the right pick. The Southwire 10/3 NM-B 250 ft is specifically correct when the appliance is a 30-amp 120/240V device requiring both voltages.

10/3 Electric Dryer Wire: The Most Common Use

The single most common application for the Southwire 10/3 NM-B 250 ft is the dedicated branch circuit for a residential electric clothes dryer. Modern US residential code (NEC 1996 and later) requires 4-prong dryer receptacles, which need four conductors: two hots, a neutral, and a ground. 10/3 NM-B supplies exactly the three insulated conductors needed (the two hots and the neutral), plus the bare copper equipment ground that satisfies the fourth-conductor requirement at the receptacle.

Older homes built before 1996 often have 3-prong dryer receptacles, which were wired with 10/2 NM-B because the older code allowed the neutral to also serve as the ground (a configuration now prohibited in new installations). When replacing an older dryer in an existing 3-prong setup, you have two options: keep the 3-prong receptacle and buy a 3-prong dryer cord for your new dryer (legal if the wiring is original), or upgrade the wiring to 10/3 NM-B with a 4-prong receptacle (required in any new installation or panel work that triggers code update).

For new construction, additions, kitchen and laundry remodels, or any wiring work that requires updating to current code, the Southwire 10/3 NM-B 250 ft is the correct dryer circuit cable. A typical residential dryer circuit run from panel to laundry room consumes 25 to 50 feet of 10/3, so a 250 foot spool covers multiple dryer installs plus other 30-amp branches on the project.

10/3 for Electric Water Heaters

The Southwire 10/3 NM-B 250 ft also serves residential electric water heater branches at 30-amp 120/240V configurations. Most residential electric water heaters use 30-amp 240V dedicated circuits, and for water heaters with electronic controls, smart thermostats, or smart-home integration that need 120V power for the electronics, 10/3 supplies both the 240V for the heating elements and the 120V for the controls in a single cable run.

The most common A.O. Smith Signature 100 residential electric water heaters use a 30-amp 240V dedicated circuit. The Southwire 10/3 NM-B 250 ft is the right cable choice for these installations when the water heater includes 120V control electronics or smart features. Browse the A.O. Smith Signature 100 40 gallon electric water heater for the 40-gallon configuration, or the A.O. Smith Signature 100 50 gallon electric water heater for the larger 50-gallon configuration.

For older or simpler electric water heaters that use only 240V without 120V control electronics, 10/2 NM-B is the more common cable choice. The IB Lighting team can verify the specific cable requirement for your water heater install before you order.

10/3 for Small Air Conditioning Units

Small residential air conditioning units, including some window units, portable units, and smaller mini-split systems, often use 30-amp 120/240V service that requires the Southwire 10/3 NM-B 250 ft. The two hot conductors carry the 240V differential for the compressor, while the neutral provides the 120V reference for the control board, fan motor, and accessories. The cable provides everything the AC unit needs in a single run from panel to disconnect.

For larger central air conditioning systems and heat pumps, larger gauge cables are typically required (8 AWG or larger depending on the specific unit’s amperage requirements). The Southwire 10/3 NM-B 250 ft is specifically the right pick when the AC unit’s specification calls for 30-amp 120/240V service. Verify the manufacturer’s electrical specifications before ordering cable for any AC installation.

Code Compliance and Ratings

The Southwire 10/3 NM-B 250 ft Romex SIMpull is UL Listed and meets every requirement of the National Electrical Code (NEC) for residential branch circuit wiring. The cable carries a 600-volt insulation rating with a 90-degree Celsius temperature rating in dry locations. NM-B specifically means “Non-Metallic, B-rated,” which is the code designation for the residential branch circuit cable approved for installation in dry, indoor locations protected from physical damage by the building structure.

NM-B is not approved for wet locations, direct burial, conduit fill in damp environments, or exterior installations where the cable would be exposed to weather. For those applications, UF (Underground Feeder) cable, THHN/THWN conductors in conduit, or Type SE service entrance cable are the correct alternatives. The orange jacket color of the 10/3 NM-B is part of Southwire’s industry-standard color coding system: white for 14 AWG, yellow for 12 AWG, orange for 10 AWG, and black for larger 8 AWG and 6 AWG feeder cables. This makes visual sizing verification fast for both inspectors and crew during rough-in.

Southwire began rolling out new color codes for 3-conductor NM-B variants in 2024 (pink for 10/3, purple for 12/3, blue for 14/3) to make 3-conductor cables visually distinct from 2-conductor cables on the jobsite. Both the traditional orange 10/3 and the newer pink 10/3 are valid and code-compliant Southwire NM-B products. The IB Lighting team can confirm which color variant is currently in stock at the time you order.

Southwire 10/3 NM-B 250 ft Specifications

Southwire 10/3 NM-B 250 ft FAQs

Who the Southwire 10/3 NM-B 250 ft Is Built For

The Southwire 10/3 NM-B 250 ft Romex SIMpull is built for two clear buyer types. The first is licensed electrical contractors running residential rough-ins, kitchen and laundry remodels, water heater installations, and AC unit projects. For these buyers, 10/3 is a stocked SKU because almost every residential project includes at least one 30-amp 120/240V circuit. The SIMpull jacket pays for itself in labor savings on every long pull through joists, especially because 10/3 is the heaviest residential NM-B cable contractors regularly pull.

The second buyer is the homeowner doing a permitted electrical upgrade, particularly a dryer circuit upgrade from 3-prong to 4-prong (required when wiring is updated to current code) or a water heater replacement where the new unit’s specifications require the dedicated 30-amp 120/240V circuit. For these buyers, the Southwire 10/3 NM-B 250 ft is the same wire your electrician would pull, with no compromise on quality or code compliance.

Browse the broader IB Lighting electrical wire collection for the complete range of NM-B sizes plus other cable types. If your project includes an A.O. Smith electric water heater installation, the A.O. Smith Signature 100 40 gallon and A.O. Smith Signature 100 50 gallon models pair with the Southwire 10/3 NM-B 250 ft for the dedicated 30-amp circuit they require.

10/3 vs 12/3 Wire: Which Should You Buy?

The Southwire 10/3 NM-B 250 ft and the Southwire 12/3 NM-B 250 ft share the same three-conductor-plus-ground configuration but differ in gauge and amp rating. 10/3 is rated for 30 amps. 12/3 is rated for 20 amps. The choice between them is determined entirely by the amperage of the circuit you are wiring.

Choose 10/3 NM-B like the Southwire 10/3 NM-B 250 ft if your circuit is a 30-amp 120/240V appliance branch. This includes electric clothes dryers (the most common 10/3 application), electric water heaters at 30-amp configurations, small air conditioning units, smaller hot tubs and spas, workshop heavy equipment circuits, and 30-amp sub-panel feeders.

Choose 12/3 NM-B like the Southwire 12/3 NM-B 250 ft if your circuit is a 20-amp branch that needs three conductors. This includes kitchen counter receptacles wired as multi-wire branch circuits, three-way switch lighting on 20-amp branches, 20-amp 120/240V appliance branches with neutral reference, and similar 20-amp configurations.

10/3 vs 10/2 Wire: Which Should You Buy?

The Southwire 10/3 NM-B 250 ft and the Southwire 10/2 NM-B 250 ft share the same 10 AWG gauge and 30-amp rating but differ in conductor count. 10/2 has two insulated conductors plus a ground. 10/3 has three insulated conductors plus a ground. The choice between them is determined entirely by whether the appliance needs a 120V neutral reference in addition to the 240V differential.

Choose 10/3 NM-B if your appliance needs both 240V (for heating elements) and 120V (for control electronics, motors, lights, or accessories). This includes modern electric dryers with 4-prong receptacles, water heaters with electronic controls or smart features, AC units with control boards, and similar appliances that need both voltages on the same circuit.

Choose 10/2 NM-B if your appliance needs only 240V without a neutral reference. This includes older or simpler electric water heaters with no 120V controls, dedicated 240V baseboard heaters, and 240V-only appliances. Note that older homes built before 1996 often used 10/2 for dryer circuits because the older code allowed the neutral to also serve as the ground, but this configuration is now prohibited in new installations. For new construction or any wiring update triggering current code, 10/3 NM-B is required for dryer circuits.

Installation Tips for the Southwire 10/3 NM-B 250 ft

Pulling 10/3 Romex SIMpull through a residential framing rough-in follows the same fundamentals as smaller NM-B cables but with a few specific considerations. The cable is heavier and stiffer than 14 or 12 AWG, so drill stud and joist holes generously sized to allow the cable to slide through without binding. Holes should be at least 1.25 inches from the nearest stud edge to satisfy the NEC nail-plate requirement, and centered through the structural member when possible.

Use cable staples sized for 10 AWG to secure the Southwire 10/3 NM-B 250 ft within 12 inches of every box and at intervals not exceeding 4.5 feet along the run, per NEC code. Standard 14/2 cable staples may not provide adequate hold for the heavier 10/3 cable. Maintain at least 8 inches of free cable inside every electrical box to give yourself room to work during termination of the larger gauge conductors.

For terminations, strip about 8 to 10 inches of jacket back at each box (more than smaller cables because the conductor terminations are larger and need more working room). Use linesman pliers to make clean wire nut or device terminations. For dryer receptacle terminations, the two hots typically land on the brass screws, the neutral lands on the silver screw, and the ground lands on the green screw. Torque all terminations to the receptacle or device manufacturer’s specification. Code requires nail plates over any cable run within 1.25 inches of the stud edge to protect against drywall screws and nails.

Bulk and Contractor Pricing

The Southwire 10/3 NM-B 250 ft is one of IB Lighting’s stocked wire SKUs because contractors buy it on most residential projects that include dryer circuits, water heater work, or AC unit installations. We offer automatic volume pricing on multi-spool orders, with deeper savings on larger bills of materials. For a typical residential rough-in covering multiple 30-amp appliance circuits, a 1 to 3 spool order of 10/3 is common alongside larger 14/2 and 12/2 quantities, and these combined orders trigger our standard contractor pricing tier.

Free freight applies to every Southwire 10/3 NM-B 250 ft order regardless of quantity. Most orders ship within 1 to 2 business days and arrive within 5 to 6 business days. If you need a bill of materials priced and quoted before you order, the IB Lighting team can turn around a quote inside of a business day for most projects. Browse our complete electrical wire collection for THHN, UF, SE, and feeder cables to round out your project bill.

Browse the complete IB Lighting electrical wire and cable collection, compare against the Southwire 12/3 NM-B 250 ft (20-amp 3-conductor sibling), pair with an A.O. Smith Signature 100 40 gallon electric water heater for the dedicated 30-amp circuit it requires, explore other Southwire products, or visit our customer FAQ hub. Manufacturer technical sheets are available at the official Southwire website.