What Is the Difference Between NM-B and UF-B Wire?

NM-B (Romex) is for indoor dry locations only. UF-B (Underground Feeder) is rated for direct burial, outdoor, and wet locations. NM-B has a loose paper wrap around conductors inside a thermoplastic jacket. UF-B has conductors molded directly into a solid thermoplastic sheath, making it moisture-resistant. Use NM-B for interior walls and ceilings. Use UF-B for underground runs, outdoor circuits, and anywhere exposed to moisture.

What Size Wire Do I Need for a 200-Amp Electrical Panel?

A 200-amp residential service entrance requires 2/0 AWG copper or 4/0 AWG aluminum conductors. The most common cable type is SER (Service Entrance Rated) aluminum, typically 4/0-4/0-4/0-2/0 aluminum SER cable. Copper SER at 2/0-2/0-2/0-1/0 is also used but costs significantly more. The wire runs from the meter base to the main breaker panel.

What Is the Difference Between THHN and Romex NM-B Wire?

THHN is a single insulated conductor designed for installation inside conduit (EMT, PVC, or flexible). Romex NM-B is a multi-conductor cable with 2 or 3 insulated wires plus a ground bundled inside a thermoplastic jacket, designed for direct installation through wood framing without conduit. Use NM-B for standard residential wiring through walls and ceilings. Use THHN in conduit for garages, basements, commercial installations, and outdoor/exposed runs.

What Is 12/2 Romex Wire? Uses, Specs, and Buying Guide

12/2 Romex (NM-B) is a non-metallic sheathed cable containing two insulated 12 AWG copper conductors plus a bare ground wire, rated for 20-amp circuits. It is the standard wire for kitchen countertop outlets, bathroom outlets, garage circuits, outdoor receptacles, and any general-purpose 20-amp branch circuit in residential construction. The "12" indicates the wire gauge (12 AWG) and the "2" indicates two insulated conductors inside the sheath.

What Is 14/2 Romex Wire? Uses, Specs, and Buying Guide

14/2 Romex (NM-B) is a non-metallic sheathed cable containing two insulated 14 AWG copper conductors plus a bare ground wire, rated for 15-amp circuits. It is used for general-purpose lighting circuits, bedroom and living room outlets on 15-amp breakers, and other low-to-moderate demand branch circuits. The "14" indicates 14 AWG gauge and the "2" indicates two insulated conductors plus ground.

What Is 12/2 MC Cable? When to Use Metal Clad Instead of Romex

12/2 MC (Metal Clad) cable contains two insulated 12 AWG conductors plus a ground wire inside an interlocking aluminum or steel armor jacket. MC cable is required in commercial construction, exposed installations where physical damage is possible, and jurisdictions that do not permit NM-B (Romex). The metal armor provides superior physical protection compared to the plastic sheath on Romex. MC cable costs more per foot but eliminates the need for conduit in many applications.

12/2 vs 14/2 Romex: Which Wire Size Does My Project Need?

Use 12/2 Romex for any circuit on a 20-amp breaker, including kitchen outlets, bathroom outlets, garage circuits, outdoor receptacles, and laundry outlets. Use 14/2 Romex for circuits on a 15-amp breaker, including general lighting, bedroom outlets, and living room outlets. Never connect 14/2 wire to a 20-amp breaker. When in doubt, 12/2 is always the safer choice because it handles both 15-amp and 20-amp circuits.

Romex (NM-B) vs MC Cable: Which Wiring Method for My Project?

Romex (NM-B) is the standard and most affordable wiring method for residential interior walls and ceilings. MC (Metal Clad) cable is required for commercial buildings, exposed installations, and jurisdictions that prohibit NM-B. Romex costs 30% to 60% less per foot but offers no physical protection beyond its plastic sheath. MC cable costs more but its metal armor protects against physical damage, rodents, and provides better fire resistance.

10/2 Romex Wire Guide: Uses, Amp Rating, and 30-Amp Circuits

10/2 Romex is a nonmetallic-sheathed NM-B cable with two 10 AWG copper conductors plus a bare ground. It is rated for 30 amps and powers dedicated circuits such as electric water heaters, air conditioner condensers, and baseboard heat. Per NEC 334.80, NM-B cable is held to the 60 degrees Celsius ampacity column, which sets 10 AWG copper at 30 amps and pairs it with a 30-amp breaker.

What Is 10/2 Romex Wire? Uses, Specs, and 30-Amp Circuit Guide

10/2 Romex (NM-B) is a non-metallic sheathed cable containing two insulated 10 AWG copper conductors plus a bare ground wire, rated for 30-amp circuits at 240 volts. It is the standard wire for electric dryers, electric water heaters, AC disconnect sub-feeds, EV charger dedicated circuits (30-amp Level 2), and other high-draw 240-volt appliance circuits in residential construction.

14/3 vs 12/3 Romex: When You Need the Third Conductor

14/3 and 12/3 Romex both add a red conductor on top of the usual black hot, white neutral, and bare ground. You need three-conductor cable for three-way and four-way switch travelers, multi-wire branch circuits that share a neutral, and appliance circuits that use both 240-volt and 120-volt power. Use 14/3 on 15-amp circuits and 12/3 on 20-amp circuits.

What Is 14/3 and 12/3 Romex? When You Need a Three-Conductor Cable

14/3 and 12/3 Romex contain three insulated conductors (black, white, and red) plus a bare ground wire. The third red conductor is used for multi-wire branch circuits sharing a neutral, switched outlets where the switch controls only part of a receptacle, three-way switch wiring requiring a traveler wire, and 240-volt circuits requiring two separate hots plus a neutral. Use 14/3 on 15-amp circuits and 12/3 on 20-amp circuits.

UF-B Wire Buying Guide: Direct Burial and Outdoor Use

UF-B is underground feeder cable rated for direct burial and wet, sunlight-exposed locations. It powers detached garages, sheds, outdoor outlets, pumps, and landscape lighting without conduit. Per NEC Table 300.5, direct-buried UF-B needs 24 inches of cover, 18 inches under a residential driveway or in PVC conduit, and as little as 12 inches for a GFCI-protected 120-volt 20-amp residential branch circuit.

What Is UF-B Wire? The Complete Guide to Direct Burial Underground Cable

UF-B (Underground Feeder cable, Type B) is a moisture-resistant cable rated for direct burial in the ground without conduit. Unlike NM-B (Romex), UF-B has a solid PVC filler that encases all conductors in a single waterproof jacket, making it the only NEC-approved cable type for direct earth burial in residential applications. It is used for outdoor circuits, outbuildings, landscape lighting, irrigation controllers, pool equipment sub-feeds, and generator connections.

CAT 6 vs CAT 5e Cable: Which Ethernet Cable Do You Need?

CAT 5e supports speeds up to 1 Gigabit per second at distances up to 328 feet and is sufficient for most home and small office networks. CAT 6 supports up to 10 Gigabits per second at distances up to 164 feet and 1 Gigabit at 328 feet, with better interference rejection. For most home runs, CAT 5e is adequate. For new construction, home offices, and any run that will serve high-bandwidth devices for the next 10 years, CAT 6 is the recommended future-proof choice.

THHN Wire Buying Guide: Individual Conductors and Conduit Use

THHN is a single insulated building wire pulled through conduit rather than bundled like Romex. Modern THHN is dual-rated THHN and THWN-2, so it works in dry and wet locations and is rated to 90 degrees Celsius for derating. It is used for conduit runs, outdoor circuits in conduit, service and feeder conductors, and commercial wiring. Terminations usually limit you to the 75 degrees Celsius ampacity column.

CAT 6 vs CAT 5e: Which Ethernet Cable Should You Run?

CAT 5e supports gigabit speeds up to 1 Gbps over 100 meters and is fine for everyday internet and streaming. CAT 6 also delivers 1 Gbps to 100 meters but adds tighter noise control and supports 10 Gbps over shorter runs up to roughly 55 meters. For new in-wall wiring, CAT 6 is the better future-proof choice. Both use the same RJ45 connectors.

CerroMax vs Southwire Romex: Which NM-B Cable Should You Buy?

CerroMax is the premium NM-B brand manufactured by Cerrowire in Hartselle, Alabama. Southwire NM-B is manufactured primarily in Carrollton, Georgia. Both meet the same NEC and UL standards for NM-B cable and are interchangeable in any residential wiring application. CerroMax is known for consistent conductor concentricity, smooth jacket finish, and reliable stripping characteristics. The choice between the two typically comes down to pricing and availability on a given order.

SER Cable Guide: Service Entrance, Subpanels, and Generator Feeds

SER is service entrance cable, style R, used for service entrances and as an interior or exterior feeder to subpanels and equipment such as a standby generator transfer switch. It is sold in copper and aluminum. For a one-family dwelling, NEC 310.12 allows service and feeder conductors carrying the entire load to be sized at 83 percent of the rating, so a 200-amp service commonly uses 4/0 aluminum or 2/0 copper.

What Is THHN Wire? Complete Guide to Individual Conduit Conductors

THHN (Thermoplastic High Heat-resistant Nylon-coated) is a single-conductor wire pulled through conduit rather than a multi-conductor cable run through walls. It is the standard conductor for commercial wiring, service panels, conduit runs, and any installation where individual conductors are routed through electrical metallic tubing (EMT), rigid conduit, or PVC conduit. THHN/THWN-2 dual-rated wire is the current standard, adding wet-location capability.

CerroMax vs Southwire Romex: NM-B Brand Comparison

CerroMax is the NM-B Romex line made by Cerrowire, a copper building wire manufacturer based in Alabama, while Southwire is one of the largest wire manufacturers in the country. Both are UL-listed NM-B copper cable that meet the same NEC requirements and follow the same color-by-gauge convention, white for 14 AWG, yellow for 12 AWG, and orange for 10 AWG. The choice usually comes down to price and availability.

Electrical Wire Gauge Chart: AWG Size, Ampacity, and Common Uses

In residential wiring, 14 AWG handles 15 amps, 12 AWG handles 20 amps, 10 AWG handles 30 amps, 8 AWG handles 40 amps, 6 AWG handles 55 amps, 4 AWG handles 70 amps, and 2 AWG handles 95 amps. Smaller AWG numbers mean larger, heavier-gauge wire. Wire gauge must always match the circuit breaker size: never protect 14 AWG wire with a 20-amp breaker, and never protect 12 AWG wire with a 30-amp breaker.

How to Run Wire in an Existing House Without Opening the Walls

Running wire through finished walls requires using a fish tape or fish sticks to navigate through wall cavities, drilling through top and bottom plates to pass between floors, and using drill bits with attached wire guides to pull cable through insulation. Key techniques include finding the shortest path between the electrical panel and the outlet location, using the attic or crawl space to bypass most wall obstructions, and making strategic access holes that can be patched with standard drywall repair kits.

Wire Gauge Chart for Common Household Circuits

For common copper NM-B Romex circuits, 14 AWG is rated for 15 amps, 12 AWG for 20 amps, 10 AWG for 30 amps, 8 AWG for 40 amps, and 6 AWG for 55 amps. These follow the 60 degrees Celsius column of NEC Table 310.16 because NEC 334.80 limits NM cable to that column. Always match the wire gauge to the breaker amperage, never put a smaller wire on a larger breaker.

How to Run Wire in an Existing House Without Opening Walls

You can run new wire in a finished house by fishing cable through hidden paths instead of opening walls. The most common routes are dropping cable down from the attic, pushing it up from a basement or crawlspace, and pulling it between boxes using fish tape or flexible glow rods. Flexible drill bits let you bore through top and bottom plates from a single access hole. Plan the path, then fish to each opening.

What Wire Do I Need? How to Choose the Right Electrical Cable for Any Project

The right wire depends on three factors: where it will be installed (indoors in walls, exposed, or underground), how many amps the circuit needs (which determines the gauge), and whether you need multiple conductors in one cable or individual conductors in conduit. For standard indoor residential work, use NM-B (Romex) in the correct gauge. For outdoor and underground runs, use UF-B. For conduit work, use THHN. For exposed or commercial installations, use MC cable.

What Is SER Cable? Service Entrance Cable for Subpanels and Generator Feeders

SER (Service Entrance cable, Round) is a multi-conductor cable used to feed residential electrical panels, subpanels, and generator transfer switches. It contains multiple aluminum or copper conductors inside a tough PVC outer jacket and is rated for service entrance and feeder applications. Common uses include feeding a detached garage subpanel, connecting a generator transfer switch to the main panel, and supplying 60-amp to 200-amp subpanel installations.

What Wire Do I Need for a New Circuit? A Simple Decision Guide

Pick wire in three steps. First, set the gauge by the circuit amperage: 14 AWG for 15 amps, 12 AWG for 20 amps, 10 AWG for 30 amps. Second, choose the cable type by location: NM-B Romex for dry indoor runs, UF-B for direct burial outdoors, THHN for conduit, and SER for service or subpanel feeders. Third, set the conductor count by the load, two-wire for most circuits and three-wire when a neutral or extra hot is needed.

How Many Outlets Can You Put on a 20-Amp Circuit?

The National Electrical Code does not set a fixed limit on the number of receptacles on a general-purpose branch circuit in a home. The common rule of thumb is about 10 outlets on a 20-amp circuit and 8 on a 15-amp circuit, based on roughly 1.5 amps per outlet and the 80 percent loading guideline. A 20-amp circuit uses 12 AWG copper wire.

Electrical Wire Color Code Explained

In standard US residential wiring, black, red, and blue conductors are hot, white or gray is the grounded neutral, and green, green with a yellow stripe, or bare copper is the equipment ground. The code requires white or gray for the neutral and green or bare for the ground. Hot conductors must be any color other than those, with black and red being the most common.