Can Romex Be Run In Conduit? When, Why & How: Full Guide

When doing electrical work around the house, it’s important to have sufficient knowledge to complete the tasks safely and successfully. When planning to use Romex wiring in your home, you need to be familiar with the conductor and its specifications, including whether you can run the wiring inside a conduit.

Running Romex in conduit is common practice but is not always essential. Conduits are often used to protect Romex in areas where it might get damaged by:

• water
• extreme weather
• people
• animals

Using conduit also reduces safety hazards and makes the installation well-organized and neat-looking.

When installing electrical wiring, it is crucial to understand the wires you intend to work with. If you’re considering installing Romex, this guide provides the knowledge needed to run this brand of non-metallic sheathed wire effectively and without creating unnecessary safety hazards.

NOTE: Wondering if a GFCI outlet can be wired on a switch? Read my article here to learn all you need to know!

Running Romex In Conduit: Necessary Or Advantageous?

Before running any electrical wire in a home, one of the vital questions to ponder is whether using a length of conduit is necessary or advantageous.

In the case of Romex wire, the answer to this question is straightforward. It is not always necessary to install this type of indoor electrical conductor with a conduit.

However, using conduit is beneficial in some Romex installation situations, and might even be essential depending on the:

• application
• budget
• materials

Let’s look at when you might want to run Romex in conduit.

When To Run Romex In Conduit

As noted, it is not always necessary to run Romex in conduit. Having said this, sometimes installing Romex with conduit is advantageous or even essential.

The National Electrical Code (NEC) requires that Romex wires are not left exposed in the home. To comply with legal regulations, Romex must be prevented from dangling by being fastened firmly to or covered by:

• conduit
• walls
• insulation

HOT TIP: Refer to your local authorities for the specific rules applicable in your area.

This regulatory requirement means you might consider using conduit when running Romex in open parts of your home, like living areas.

A conduit is also an option worth considering when installing Romex in spaces that are potentially subject to flooding, like:

• attics
• garages
• basements

When running Romex in attics and garages, a conduit provides additional mitigation against dramatic temperature changes.

Conduit is also a wise choice when you need to install an extensive length of Romex. PVC conduit, (sold on Amazon), is often the most affordable option for running Romex between two distant points.

Nevertheless, it is crucial to emphasize that you don’t need to use conduit when Romex is installed within wall interiors and underneath floor surfaces. A conduit tube is also unnecessary when the wire is inside insulation or fastened securely along its length, provided the wire isn’t at risk of getting wet.

Why Run Romex In Conduit?

There are several reasons to run Romex wiring in conduit. The principal reasons are:

• protection from damage
• safety
• organization
• aesthetics

#1: To Protect The Wire From Damage

Conduit serves to protect Romex from being exposed and damaged. Though Romex has a PVC sheath around its internal conductor wires, this covering provides limited protection against:

• water
• fire
• temperature extremes
• scratches
• dents
• cuts
• corrosion

Romex also needs protection because the wire is for permanent installations, so it is vulnerable to corrosion over time.

Using conduit is one of the most common Romex wire defense strategies. Conduit tubes are considerably thicker than Romex sheaths and are composed of more durable materials.

Most types of conduit tubing are water-proof and can withstand long-term wear-and-tear and temperature fluctuations.   

#2: Romex in Conduit for Safety

The second closely-related crucial reason to run Romex in conduit is safety. If Romex gets damaged, the internal conductors can pose serious hazards to:

• people
• pets
• buildings

Conduit tubing helps reduce the risks of electrocution and fires caused by damaged and exposed Romex wiring.

Using a conduit also keeps the wire from dangling and coming into contact with people and animals.

#3: Well-Organized Romex Installation

The third reason to run Romex in conduit is to ensure the installation is well-organized. Conduit tubes provide an orderly way to arrange the wire and demarcate its location, which is advantageous if the wiring needs to be:

• checked
• maintained
• repaired
• replaced

#4: Neat And Clean Appearance

A fourth, closely-related reason to use conduit when installing Romex wiring is aesthetics. Running Romex in conduit has a neater, cleaner appearance than loose or open wiring, which looks untidy and unprofessional.

How To Run Romex In Conduit

If you’re considering the possibility of installing Romex in conduit, here is some essential knowledge to guide you along the path to success.

Before we get into the practicalities of installation, let’s briefly examine Romex and conduit in more detail.

Romex: An Everyday Home Electrical Conductor

Romex is a brand of non-metallic sheathing electrical wire typically for indoor home use. The wire is often the conductor connecting lighting and plug outlet circuitry and appliances such as:

• clothes dryers
• refrigerators
• water heaters

The Romex sheath surrounds a bare copper wire (ground), and two to three conductors (hot and neutral) covered with layers of plastic insulation. 

The different types of Romex are rated according to their gauge (diameter) and the number of insulated conductors the wires have. Each category conducts a specific amperage and is better suited for some applications than others.

A two-number classification represents the various categories of Romex, with the first digit indicating the gauge and the second digit indexing the number of conductors. Here are the most widely-used types of Romex:

• 12-2 (20 amps)
• 14-2 (15 amps)
• 10-2 (30 amps)
• 10-3 (30 amps)

12-2 is a ubiquitous type of Romex in the home and is an optimal wire for lighting and outlet circuits. Romex 12-2 is also suitable for connecting refrigerators.

Romex 10-2 is usually for connecting electric water and wall heaters, while 10-3 is for clothes dryers. Romex marked as 14-2 is primarily limited to lighting circuit applications.

National Electrical Code Regulations For Romex Installation

When installing Romex with or without conduit, it is necessary to comply with the National Electrical Code (NEC). Before installation, consult the NEC’s regulations and contact your county building inspector to ascertain if there are specific local regulations that also apply to your project.    

Local variations aside, the NEC regulations broadly stipulate that Romex must:

• not remain exposed after installation
• be installed as permanent wiring
• not be used in residential buildings higher than 3 stories

One of the most critical of these regulations highlighted above is that Romex must not be left exposed where it might get damaged or pose a safety hazard. The NEC regulations advise that Romex is protected, by running the wire inside:

• conduit
• insulation
• flooring
• building walls

If installing Romex outside of the coverings stated above, the regulations require you to fasten the wire taught and securely every 4 to 5 feet with:

• hooks
• nails
• clamps

NOTE: The NEC regulations also specify that Romex must be firmly fastened about 12 inches from the junction box.

Types Of Conduit for Romex

Now we have a basic understanding of Romex, and the regulations governing its installation, let’s have a closer look at a conduit. Some of the most widely-installed types that are sold on Amazon are:

• PVC conduit
• electrical metal tubing (EMT)
• flexible metal conduit (FMC)

PVC (polyvinyl-chloride) conduit is the most budget-friendly type of protective tubing for Romex and other electrical conductors. PVC conduit tubing is an excellent choice when installing Romex across large areas. PVC conduit is water-proof and doesn’t corrode.

This type of conduit is rigid but it is relatively easy to cut through and join with glue. Conduit made of PVC is also malleable when heated with the appropriate tools. These physical characteristics mean that the PVC conduit is adaptable to your specific spatial requirements.

Electrical metal tubing (EMT) is a galvanized aluminum conduit that is lightweight and thin while also having significant rigidity. EMT is unusual because it has electrical conductivity and enhances the amount of current passing through the wires inside it.

TIP: The wiring for indoor lighting circuits is often installed with EMT.

A flexible metal conduit (FMC) is a coiled conduit usually made of aluminum or steel. FMC is more expensive than PVC conduit. FMC also lacks the durability of PVC conduit and is only installed in dry areas of the home.

However, FMC is more flexible than its PVC and EMT cousins, so this conduit is ideal for installation in small spaces and around convoluted angles.

Steps To Installing Romex In Conduit

Installing Romex in conduit is not particularly complicated. These are the essential steps to follow.

Step #1:

Select an appropriate type of conduit for the task, which will depend on several factors, such as the:

• kind of outlet or appliance being connected
• length of the wire
• size of the area
• possible risk of environmental damage (water and temperature extremes)

Step #2:

Insert the Romex into the conduit. If you’re using PVC conduit, cut and adapt the conduit to the space before inserting the Romex wire.

Step #3:

Place the conduit with the Romex inside along the intended route.

Step#4:

Secure the conduit into position with fasteners.

Conclusion

It is possible to run Romex in conduit tubing. In some cases, it is beneficial to use a conduit to install Romex.

Conduit helps to protect Romex from damage and minimizes potential safety hazards. Using conduit tubes also makes the installation neater and more well-organized.

Conduit is unnecessary, and potentially problematic if Romex is run:

• under the floor
• behind a wall
• inside insulation
• firmly secured out of sight
• in an area of potential water damage

However, it is advisable to install Romex in the conduit if the wire is not covered and protected by:”

• insulation
• walls
• flooring
• fasteners

You might also be interested in:

• Can Romex Touch Insulation?
• Can Romex be Used in a Commercial Building?