Romex is one of the most popular types of non-metallic cables used in American homes. It is generally protected by conduits and runs through walls.
However, there are instances when you might have to run it on finished concrete surfaces.
The easiest way to secure Romex to concrete is with non-metallic cable straps and concrete nails. You might be able to use staples – in pre-drilled holes – or masonry cable clips in areas that are difficult to reach. To secure the cable:
- Check the regulations in your area and make sure running Romex in exposed areas is legal.
- Plan the route and establish fastening spots.
- Secure Romex to concrete with cable straps and nails.
- Drill fastening holes in difficult-to-reach spots.
- Secure the Romex cable in these spots with non-metallic cable staples or clips.
Running Romex along with concrete in exposed areas might or might not be possible in your area.
Consult your local code or contact the building department to make sure you respect the regulations.
What To Know Before Installing Romex Cables
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Romex is a brand name for a type of electrical conductor with non-metallic sheathing. This cable type is generally employed in branch wiring for residential applications.
It is so popular that people now refer to these cables as Romex regardless of the brand.
While there are different types of cables Romex manufactures, a few NEC regulations apply to all of them. Here are the things to know before installing and securing them to concrete:
- Romex conductors cannot be installed in buildings that are over three stories tall.
- You cannot use overdriven staples or bent nails to secure them to surfaces.
- The first fastener should be installed no further than 12 inches from the junction box or panel to which the cable is attached to. A fastener is needed for each 4-1/2 feet of cable.
- Romex cables can only be used as permanent wiring. You cannot use them as substitutes for extension cords or appliance wiring.
According to most building codes, non-metallic (NM) sheathed wiring can be used for branch circuits inside a building. You can also run them exposed or run them through masonry cells and voids that are not exposed to dampness.
However, this cable is not suitable to use in areas exposed to dampness or in areas where the cable may be subject to physical damage. Also, Romex cables can’t be embedded in non-cinder concrete.
Securing Romex To Concrete
Following the rules above is paramount to minimizing the fire hazard. Depending on the application, the cable might also have to be wired in a GFCI terminal in the junction box or panel.
With this in mind, here’s how to secure Romex to concrete:
Things You’ll Need:
- Non-metallic cable straps
- Concrete nails
- Hammer
- Non-metallic cable stapler (optional)
- Staples (optional)
- Drill (optional)
- Masonry drill bit (optional)
- Screwdriver (optional)
- Masonry cable clips – self-adhesive (optional)
1. Check The Regulations In Your Area
The above are general guidelines that apply in most areas in jurisdictions. However, you should check your local code before running Romex exposed – or at all.
For instance, NM cables are generally not used in Chicago, but other municipalities in Illinois allow them.
2. Plan The Route
Whether you want to run electricity to a kitchen island or have to install an exposed wire from a junction box to a new fixture, you should plan the route before buying the cable and fasteners.
This step allows you to decide the best route to run the wire so that it’s not exposed to moisture or physical damage. You can also mark all fastening spots and buy an appropriate quantity of fasteners.
To recap, the first fastener should be installed within the first 12 inches from the panel or junction box the cable is connected. All additional fasteners must be installed at a distance of no more than 4-1/2 feet from one another.
3. Secure Romex To Concrete With Cable Straps
Cable straps are the easiest to install on concrete surfaces. Most straps come with nails, so you should check the nails are suitable to use with concrete or other masonry materials.
Alternatively, you can purchase the straps and nails separately. You can find all the necessary supplies at a local home improvement store.
Use the marks you did earlier to install the cable and fasten it to concrete according to the planned route.
4. Pre-drill Holes For Cable Staples
Stapling electrical cables to a wall is common practice when securing them to drywall or wood surfaces. However, driving staples in concrete or masonry is challenging.
Predrilling the staple holes can make it easier if you have to staple lengths of cables in narrow or difficult-to-reach spots where you can’t fit a hammer.
Use a masonry drill bit with a diameter slightly smaller than the one required by the staples.
5. Secure Romex In Hard-To-Reach Areas
You can now staple the cable to the concrete surface – staplers are generally narrower than a hammerhead and could fit into a difficult spot.
Alternatively, you can use straps and nails, driving the nail into the surface with the handle of a screwdriver.
You can also fasten Romex in a difficult spot with self-adhesive masonry clips. This peel-and-stick method is perfect for areas where you can’t fit any kind of tool; however, the method is temporary.
Even if these clips are designed for masonry surfaces, they will peel off sooner or later. You should check the cable periodically and re-secure the lengths as needed.
Keep in mind that using insufficient fasteners can lead to sagging, premature damage, and an increased risk of fire.
Key Takeaways
Romex – and other types of non-metallic cables – are generally safe to run exposed in dry areas that are not prone to physical damage.
Fastening Romex with cable straps and masonry nails is the easiest way to secure it to concrete. Alternatively, you can drive staples in pre-drilled holes or use peel-and-stick cable clips.
No matter what fasteners you use, remember to install the first one within the first 12 inches from the junction box or panel. Also, the maximum distance between fasteners is 4-1/2 feet.