A new outlet in a finished living room and a circuit running through an unfinished basement may need very different wiring methods. That is the practical difference between Romex and conduit wiring: one is a cable assembly commonly used inside finished walls, while the other is a protective pathway that can house individual electrical wires.

Neither option is automatically better. The right choice depends on where the wiring is installed, whether it could be damaged, local code requirements, moisture exposure, future access, and the electrical load being served. For homeowners planning a renovation, EV charger, hot tub, panel upgrade, or basement project, knowing the distinction can help make contractor recommendations easier to understand.

What Is Romex Wiring?

Romex is a widely used brand name that homeowners often use to describe nonmetallic-sheathed cable, usually labeled NM-B. It bundles insulated current-carrying wires, a bare or insulated grounding wire, and an outer plastic jacket into one flexible cable.

For a standard 120-volt household circuit, a common example is 14/2 or 12/2 NM-B cable. The first number refers to wire size, and the second refers to the number of insulated conductors inside the cable. A 12/2 cable, for example, typically includes a black hot wire, a white neutral wire, and a bare ground wire. The ground is not included in the “2.”

Romex is popular because it is efficient to install in dry, protected areas. Electricians can run it through drilled holes in wood framing and behind drywall without having to install a separate raceway first. That makes it a practical option for many bedrooms, living rooms, kitchens, and other finished indoor spaces.

The outer jacket is protective, but it is not armor. NM-B cable is not intended for wet locations, direct burial, or places where it is likely to be struck, crushed, or otherwise physically damaged. It also must be supported and protected correctly where it passes through framing or comes near the face of a stud.

What Is Conduit Wiring?

Conduit is a tube or raceway that protects electrical conductors. Rather than pulling one fully assembled cable through a wall, an electrician may install conduit and then pull individual wires through it. The conduit creates a defined, protected route for the electrical system.

Conduit can be made from metal or plastic. Common residential types include electrical metallic tubing, often called EMT; rigid metal conduit; flexible metal conduit; and PVC conduit. Each has a different use. PVC is common underground and in damp or corrosive environments, while metal conduit may be selected where stronger physical protection or an exposed, finished appearance is needed.

A conduit system may contain THHN or THWN-rated conductors, depending on the location and installation requirements. These individual wires are rated differently from NM-B cable, which is why an electrician cannot simply substitute one for the other without considering the environment and code.

Conduit can be installed inside walls, across unfinished basements, in garages, outdoors, underground, and in certain service areas. It is especially useful where wiring remains exposed or may need a higher level of protection.

Difference Between Romex and Conduit Wiring at a Glance

The most direct difference between Romex and conduit wiring is that Romex is the cable itself, while conduit is the protective channel that carries wires. In many installations, the comparison is really NM-B cable versus individual conductors installed in conduit.

Romex is usually faster and less expensive to install in dry, concealed residential areas. It requires fewer parts and less labor, which can make it a sensible choice during whole-home rewiring or a straightforward interior remodel.

Conduit generally takes more planning and labor. The raceway must be properly sized, secured, routed, and fitted with approved connectors. Wires must be pulled without damaging their insulation, and conduit fill rules limit how many conductors can occupy a given size of pipe. Those details can add cost, but they deliver meaningful protection and may be required in the location.

There is also a future-access advantage with conduit. If a properly installed conduit run has room for additional conductors, it may be possible to pull in new wiring later. That can help with a workshop upgrade, a detached garage, a smart-home addition, or another planned electrical change. It is not a guarantee, though. Long runs, tight bends, undersized conduit, and crowded conduit can make future work difficult.

Where Romex Usually Makes Sense

NM-B cable is commonly used inside the dry, protected cavities of a home. A typical example is wiring a new bedroom circuit through wall studs and ceiling joists before drywall is installed. It can also be a good fit for a finished-home repair when an electrician can fish the cable through walls without exposing it to damage.

It is often the practical choice when the wiring will be concealed behind drywall, paneling, or another approved finish. The cable must still be installed according to code, including proper fastening, box fill limits, and protection from screws and nails.

Romex may also be used in accessible spaces such as basements or attics when it is installed in a way that protects it from damage. An unfinished basement is not automatically a place for loose cable. Wiring running across exposed framing, near storage areas, or along walls may need additional protection or a different wiring method.

When Conduit Is the Better Choice

Conduit is often selected or required when cable needs more protection than a plastic jacket can provide. In a garage, utility room, unfinished basement, crawlspace access area, or workshop, exposed wiring can be vulnerable to ladders, stored items, tools, and everyday contact. Conduit creates a more durable installation.

Outdoor circuits are another common example. Wiring for landscape equipment, detached structures, HVAC equipment, generators, and some EV charging equipment may need a wiring method rated for weather, sunlight, moisture, burial depth, and potential impact. The exact material and conductor type matter just as much as the conduit itself.

Conduit is also common for certain equipment connections and service-related work. A new electrical panel, a whole-home generator, or a Level 2 EV charger may involve exposed runs near the panel or equipment location. A qualified electrician will determine whether conduit is required, preferred, or unnecessary based on the path, environment, equipment instructions, and locally adopted electrical code.

Safety and Code Details Homeowners Should Not Guess At

The National Electrical Code provides broad rules for wiring methods, but counties and municipalities can adopt different code editions and local requirements. A method that looks acceptable in one home may not meet requirements in another jurisdiction.

Wire sizing is another area where appearances can mislead. A 20-amp circuit typically needs 12-gauge conductors, while a 15-amp circuit may use 14-gauge conductors. Larger appliances, EV chargers, hot tubs, dryers, and HVAC equipment often need dedicated circuits with specific conductor sizes, breaker ratings, and disconnect requirements. Putting wires in conduit does not correct an undersized circuit, and using Romex does not make an installation suitable for every environment.

Moisture is particularly important. Outdoor conduit can collect condensation, which means the conductors inside must be rated for wet locations. Standard NM-B cable is not approved for wet locations, even if it is placed inside a raceway. This is a frequent source of costly mistakes in do-it-yourself projects.

Grounding, bonding, GFCI protection, AFCI protection, box sizing, and proper connections all affect whether a project is safe. These are not cosmetic details. They help reduce shock hazards, overheating, nuisance tripping, and fire risk.

Choosing the Right Method for Your Project

Start with the location. Is the wiring inside a dry finished wall, exposed in a garage, routed outdoors, buried underground, or serving high-demand equipment? Then consider the circuit’s purpose and whether you may need access for future upgrades.

For a simple interior lighting or outlet project, Romex may be the efficient solution. For exposed, outdoor, underground, or damage-prone runs, conduit may be the safer and code-appropriate route. Some projects use both. An electrician might run NM-B cable through protected wall cavities, then transition to conduit where the circuit becomes exposed near equipment.

A professional evaluation can prevent a small project from becoming a patchwork of mismatched materials and repeat repairs. Stella Electric helps homeowners across the Baltimore area assess wiring conditions, explain the options in plain language, and complete upgrades with safety and long-term use in mind.

If you are seeing damaged cable, loose exposed wiring, repeated breaker trips, or signs of overheating, do not wait for a renovation to address it. A timely electrical inspection can clarify what is behind the walls and what will keep your home protected for the years ahead.