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Can You Run Romex in Conduit? (Explained)

Generally, Romex is one of the most renowned non-metallic wiring brands. In general, we use Romex for representing non-metallic wires.

Whenever it comes to DIY projects, we use Romex cables. These cables also have plastic insulating material coverings and copper wires inside the cables.

On the other hand, we use conduit vastly for different projects related to wiring. So, you might be confused about whether you can run Romex in conduit or not.

Well, you might need to use Romex in different places. So, you have to know about the consequences of using Romex in conduit in those places.

Can you run Romex in conduit?

Romex is suitable to run in conduit. Generally, conduit protects wires from physical damage. So, it will also protect Romex. But if you don’t use conduit for Romex, it might damage more than the metallic counterparts. Moreover, you can run Romex in conduit both indoors and outdoors.

However, the medium through which you are using Romex in conduit might be different. So, let’s see whether you can run Romex in those mediums or not.


Generally, when you are using Romex outside, it is recommended to run it through a conduit. Besides, the conduit should be weather-resistant. Moreover, if you use the Romex near the utility line, it will be more protective.

This way, the Romex will be safe from both the natural effects and external damages.


When you use Romex for underground works, you will protect the Romex more. Because the underground environment is different and can be more damaging sometimes. Pressure, temperature, humidity, etc., are different there.

So, when you are working with Romex underground, you should apply a conduit for the Romex. If you run Romex in conduit for using at underground, the Romex will also remain durable.


Though conduit is more likely to use outdoors, you can also run Romex in conduit for installing indoors. It is not compulsory that you only have to use conduit only for outside.

Your Romex can get damaging environment indoors also. So, it depends on you whether you want to use conduit for Romex indoors or not. However, conduit provides overall protection.

Flex conduit:

You can run Romex in flex conduit. This type of conduit is used where there are many vibrations. So, we use a flex conduit so that the Romex can be safe from vibrational damage. So, you can use a flex conduit for protecting Romex.

Metal conduit:

You should not run Romex in a metal conduit. Because metal conduit has some drawbacks. For example, the metal conduit can get corroded easily. Besides, if there is a 90 degrees bend, the metal conduit might lose its stability.

Moreover, the metal conduit can induce heat retention problems. So, it is not recommended to run the Romex in a metal conduit.

Plastic conduit:

Running Romex in a plastic conduit is not recommended. Because plastic materials are supposed to trap heat and produce heat-related degradation. Moreover, plastic will likely be damaged by environmental effects like temperature, acidity, pollution, etc. So, you should not run the Romex in a plastic conduit.

PVC conduit:

PVC conduit is made of polymer material. So, this type of conduit traps heat, and passing heat is difficult. When the conduit holds more heat, it will affect the Romex as well.

Moreover, it will be hard for Romex to remain durable in a heated place. The conduit will be degraded and the Romex will also be damaged. So, you should not run Romex in PVC conduit.

Liquid-tight conduit:

You can also run Romex in a liquid-tight conduit. This type of conduit protects the wires from liquid and moisture. So, wherever you are using the wires, there will be no fear of corrosion from liquid or moisture.

A liquid-tight conduit is one type of flexible conduit. So, you can use this conduit for Romex protection.

Is it code to run Romex in conduit? Are you allowed to run Romex in conduit?

Generally, it is not compulsory or codes to run Romex in conduit. But it is recommended to encase the Romex in conduit where there is a chance of physical damage of the wires.

The main function of a conduit is to save the wires from environmental or physical damage. So, if you are installing the wires outside or underground, it will be wise to use a conduit. In this perspective, you are allowed to run Romex in conduit.

But sometimes, the wrong choice of conduit might damage the Romex more. For example, metal and PVC conduits are suitable for the Romex. Moreover, when the Romex has less chance of damage, running Romex in conduit is not essential.

So, it is not coded to run Romex in conduit but it is recommended based on the installing situation. That means it is code to run Romex in a conduit in damaging or corroding environments.

3 reasons why you can run Romex in conduit

Now that you know you can run Romex in conduit, you might want to know the reasons behind it. So, let’s see the reasons why you can run Romex in conduit.


The main function of the conduit is to protect non-metallic wires from physical damage. Generally, the damage to the wires might come from the environment or any mechanical deformation.

So, when you run Romex in a conduit, the conduit will protect the Romex from different types of damages. Moreover, the conduit will also protect the wires from heat, pressure, and other things.


Another important factor that conduit does is saving the Romex from harsh weather. For example, when you use Romex outdoors or underground, the weather puts many effects on the Romex.

So, if you run Romex in a conduit, the outdoor or underground weather effects will remain resistant to the conduit.

Durability of wire:

Generally, when we use Romex without any conduit, the wires might damage soon. But when you run Romex in a conduit, the wires can last a long time. So, the durability of Romex increases.

How much Romex can I put in conduit? How far can you run Romex in conduit?

How much Romex you can put in the conduit depends on the size of the conduit and the diameter of the wires. Because the more the diameter of the wire, the less amount of wire you can put in a conduit.

For example, if the conduit is of ½ inch diameter, you can put 9 Romex wires of 12 gauges. But if the wires are 14 gauges, you can put up to 12 wires.

On the other hand, if the conduit is ¾ inch, you can put 16 wires of 12 gauges. But if the wires are 14 gauges, you can put up to 22 wires. So, how far you can run Romex is conduit depends on the size of the wires and conduit.

Does Romex have to be in conduit in the garage? What size conduit do I need for 6/3 Romex?

Yes, Romex has to be in conduit in the garage. Generally, in a newly finished garage, when you run Romex on the wall, the Romex might get damaged.

Moreover, the environmental effects can also affect the wires. So, Romex will be safe in conduit in the garage.

Moreover, 6/3 Romex will require a large conduit. Generally, if you want to run a 6/3 Romex, you will need a 2 inches conduit to run the wire.

This large conduit will keep the Romex free and flexible. Otherwise, the Romex might get abraded with the wall of the conduit.

How to run Romex in conduit?

If you want to run Romex in conduit, you have to follow an appropriate way. Otherwise, the Romex might go through physical damage from the wrong installation process. Let’s see how you can run Romex in conduit.

Lubricating the wire:

You can use lubricant on the wire that comes in the form of gel, soap, or foam form. Using a lubricant will make the wire easy to insert into the conduit.

Attach pull-string and position the mouse:

Now you have to attach a pull string to the Romex wire loop. Generally, this wire loop runs through a mouse that pulls the wires easily.

Then you have to set the pull string to the mouse and position it in the conduit.

Using a shop vacuum hose:

Now you have to set the shop vacuum hose with the other end of the conduit. Then you have to turn it on. After the mouse is out, you have to turn off the vacuum.

Fasten the strings:

Finally, you have to secure the strings with Romex by fastening and lubricating the wire.

Final Thoughts

You can run Romex in conduit for the protection of wires. Generally, a conduit helps the wires to be protected from physical damage. Moreover, a conduit saves the Romex from environmental effects. Especially, while running Romex outdoors or underground, a conduit is a must.