6/3 UF-B (Underground Feeder) Cable with Ground is a specialized, flat-profile branch circuit and feeder wire engineered specifically for direct-burial underground applications. Unlike standard interior building wire (like NM-B Romex), which requires a protective conduit when buried, UF-B features a solid, injection-molded polyvinyl chloride (PVC) jacket that completely fills all voids between the conductors. This unique construction encapsulates each individual wire in a protective shield, protecting the copper elements from direct exposure to underground moisture, continuous dampness, soil acids, and rot.

Rated for operations up to 600 Volts, 6/3 UF-B consists of three insulated phase/neutral conductors and one bare copper ground wire. It serves as an all-in-one distribution line for safely running heavy electrical loads from a primary residential or commercial service panel out to unattached exterior structures without needing a continuous run of rigid PVC or metal conduit through the trench.

ELECTRICAL AMPACITY & PERFORMANCE DATA

Due to its heavy, solid plastic encapsulation, heat dissipates more slowly from UF-B cable than it does from traditional open-air wires. Per electrical safety standards, its current capacity must always be adjusted downwards:

• Maximum Current Capacity (Normal Conditions): 55 AMPS Ampacity limits are calculated using the 60C temperature column in accordance with National Electrical Code (NEC) Article 340. Even though the interior copper conductors are insulated with 90C thermoplastic (THHN/THWN equivalents), the overall cable installation is structurally restricted to the 60C limit for safety margin overhead.

Key Features

• Direct-Burial Self-Containment: Specifically listed for direct placement into earthen trenches without requiring a continuous conduit pipe run, dramatically reducing trenching material and labor costs.

• Solid PVC Core Encapsulation: Unlike standard house wire, which contains open air pockets inside its sheath, the gray PVC jacket on UF-B is pressure-extruded into every void, freezing the internal elements in place and stopping corrosive water tracking.

• Annealed Copper Conductors: Constructed with three high-grade 6 AWG stranded copper conductors providing excellent conductivity, high thermal performance, and pull-strength resilience.

• Corrosion & Sunlight Resistance: The outer gray PVC compound is heavily treated with UV inhibitors (SUN-RES) and specialized chemical stabilizers, allowing sections of the cable to run in open sunlight along the side of buildings without degradation.

Common Applications

• Sub-Panel Feeders to Outbuildings: Safely routing bulk 240V power lines out to detached residential garages, agricultural barns, backyard workshops, and storage sheds.

• High-Draw Outdoor Equipment: Supplying dedicated power to large electrical installations such as geothermal heat pump compressors, high-amperage hot tubs/spas, and multi-stage swimming pool filtration systems.

• Electric Vehicle (EV) Charging Stations: Providing a direct underground connection to remote, free-standing outdoor Level 2 EV charging pedestals or detached carports.

Cable Layer Architecture (From Core to Jacket)

1. Phase/Neutral Conductors: 3 independent 6 AWG stranded bare copper cores.

2. Conductor Insulation: Color-coded (Black, Red, and White) high-dielectric Polyvinyl Chloride (PVC) jacketed with a smooth Nylon skin layer.

3. Ground Conductor: One (1) uninsulated, bare stranded copper ground conductor (sized symmetrically at 6 AWG).

4. Encapsulated Web Sheath: Heavy, unified injection-molded Gray PVC jacket that locks the parallel conductors into a rigid flat-ribbon assembly.

Technical Specifications

• Conductor Size: 6 AWG

• Number of Insulated Conductors: 3

• Conductor Material: Annealed soft-drawn copper

• Conductor Stranding: 7 Strands per core

• Grounding Configuration: 1 bare copper grounding wire (6 AWG)

• Insulation Type: PVC with Nylon Covering (THHN/THWN-2 internals)

• Outer Jacket Material: Sunlight-resistant, moisture-impervious Gray PVC

• Cable Geometry: Flat profile (approx. 0.42 inches x 1.15 inches)

• Approximate Net Weight: Approx. 370 lbs per 1000 feet

• Voltage Rating: 600 Volts Maximum

• Temperature Limits: Dry locations up to 90C / Restricted to 60C for operational ampacity calculations

• Compliance Standards: UL Standard 493 (Underground Feeder Cables), ASTM Spec Requirements, National Electrical Code (NEC) Article 340, Federal Specification JC-30B, RoHS Compliant

Technical Note Regarding Installation: When burying 6/3 UF-B directly into the ground, NEC Article 300.5 mandates a minimum burial depth of 24 inches under standard soil configurations to safeguard the line against lawn aerators, shovels, or surface activity. Where the cable emerges from the deep trench to climb up a post or foundation wall to enter an electrical box, it is highly vulnerable to lawn mowers and string trimmers. In these exposed areas, the cable must be protected inside a schedule 80 PVC or rigid metal conduit sleeve starting from 18 inches below the ground line up to its final termination point.

CABLE TYPE: 6/3 AWG UF-B Underground Feeder and Direct Burial Cable (Stranded Copper with Bare Ground / Flat Gray PVC Outer Jacket)

DISCLAIMER: The technical information provided is for general reference only. All underground electrical distribution systems must be installed in strict compliance with the National Electrical Code (NEC), local municipal ordinances, and under the oversight of a licensed electrician. Always confirm trench depths, structural crossing protections, and final panel breaker pairings with local code enforcement bureaus before initiating an excavation.