What Size Screws Are For An Electrical Box? (Find Out Now!)

Upgraded Home Team
by Upgraded Home Team

Most new electrical boxes and configurations will come with the needed electrical screws in the package. If you are simply replacing an electrical box or have lost the original screws, you may need to purchase new screws to attach your electrical box safely. Determining the correct size and type of electrical screw can be difficult, though, especially with so many screw options available on the market.

The most common size screw to use in an electric box is a 6-32 flathead screw. For heavier applications, like ceiling lighting and ceiling fans, an 8-32 screw will work better. Ground screws in electrical boxes are always 10-32 and must be painted visibly green.

Remember, screws that are flat head work best because they will sit flush with your electrical application. The screw head can be either Philips or slotted screw, but usually, a slotted screw is the electrician’s preferred type. Be sure to always work with stainless steel or zinc-coated screws when working in electrical applications. Not only are these screw materials the safest, but they will also keep the physical, electrical box in good condition.

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How Is a Screw Measured?

It may seem like a different language looking at how a screw is measured. The terminology for sizing relates to three pivotal measurements of the screw. These measurements include gauge, threads per inch, and length.


The gauge measurement determines the diameter of the screw itself. Screw diameters are available in a range of sizes to accommodate different projects. Most commonly, a #6 gauge is used for electrical boxes and other electrical work. The gauge measurement is the first number listed when giving a screw size.

Threads Per Inch

Next, the threads per inch measurement determines how many individual threads exist in a one-inch screw shaft. When working with electrical boxes, most electricians recommend using 32 threads for every inch of the screw. This number is always given after the gauge of the screw.


Lastly, the length of the screw is given in the screw description. Length is an important measurement, especially when it comes to working with electrical boxes. Usually, a one-inch screw is perfect for working with standard outlets or switches.

How To Choose An Electrical Box

What Screw Material Should Be Used for Electrical Boxes?

When working with electrical boxes, you want to ensure you have the right size and diameter screw and the suitable screw material. Electricity can be dangerous, and working with the wrong screw material can inadvertently damage an electrical box or conduct electricity incorrectly.

Always be sure to use stainless steel screws when working with electricity. These screws are safe and intended for electrical use. You want to avoid using drywall screws and sheet metal screws. While these screws may fit the needed application, they can do more harm than good and potentially damage your electrical boxes. In most areas of the country, drywall screws and sheet metal screws will not pass electrical code in most residential homes.

What Screws Should I Use For a Cover Plate?

A face cover plate is the part of an electrical construct that covers the electrical outlet or switch to keep it safely protected inside the wall. Face cover places usually use slightly different electrical screws that have an oval shape, flat head. These screws will commonly be 6-32 and be about 5/16 inches in length. When the cover plate is covering an empty outlet box, a one-inch length can be used.

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What Screws Should I Use For Switches and Outlets?

When attaching switches and outlets to the studs in your wall, you want to ensure a strong connection. Like other electrical screws, you will want to use a 6-32 screw for the electrical outlet. However, try using a larger one-inch screw to ensure the screw is safely anchored to the studs in your wall. Most new electrical outlets will come packaged with the needed screws.

What Screws Should I Use For Recessed Outlets?

If you have an area of a thicker wall than usual, a recessed outlet may have to be used. This outlet type features an extended electrical box to help accommodate the added thickness. The deeper box will also require longer screws.

To attach a recessed outlet, usually a 6-32 1.5 inch length screw should work perfectly. While more extended screw options are available in the 6-32 inch size, you never want to use something longer than two inches to attach an electrical box. Remember that the deeper recessed box will also require longer screws than usual to attach the face cover plate as well.

What Screws Should I Use For Ceiling Lights?

Usually, ceiling lights and ceiling fans will use a round electrical box due to the different installation style. Round electrical boxes will require slightly different screws to hold them in place. For a round electrical box, an 8-32 screw is recommended. This screw has a slightly larger diameter which makes it better suited for ceiling applications.

What Screws Should I Use for Exterior Electrical Applications?

Many residential homes have exterior outlet boxes, which create a safe and convenient way to add power and electricity to the outdoors. Many exterior outlets are identical to an interior outlet, just with added insulation and weather protection. You’ll want to use a 6-32 screw to attach your exterior outlet.

Of course, consider that many exterior outlets are placed in extra-thick walls that may add depth to your application. A slightly longer electrical screw that is 1.5 inches or 2 inches may be needed to safely and securely attach your exterior outlet to the wall. Always be sure to use a stainless steel electrical screw for exterior applications.

What Is A Ground Screw?

While there are standard electrical screws that help hold the electrical box in place, there is also a ground screw. Usually, the ground screw is thicker with a hex head and is painted green. The purpose of the ground screw is to keep the ground wire held in place, keeping your electrical outlet safe and grounded.

Usually, a ground screw is a hex head shape in either a slot head or Philips style. The screw is typically a 10-32 size and is 5/16 inches long. The ground screw is essential for a safe electrical box. In most residential areas, the screw must be very clearly painted green to pass the electrical code.

Can I Use Any Screw as a Ground Screw?

Ensuring your electrical box has a ground screw is essential for a safe installation and application. But, what happens if the ground screw options available do not fit or won’t work? Technically speaking, to meet code, a ground screw must be identifiably green in color to alert other homeowners and electricians that the screw is the ground.

However, using any 8-32 screw with a washer will work as a ground for functionality’s sake. Often, electricians report a simple stainless steel screw with a washer attached works better than a hex-head screw used to meet code requirements. Remember, though, that while this setup may function safely, it will not pass electrical code.

Where Can I Buy Electrical Screws?

Luckily, electrical screws are standard necessities for many DIYers and homeowners. These materials are regularly available at local hardware stores like Home Depot or Lowe’s. They can be purchased as a simple 2-pack or purchased in bulk for larger home products.

It is also possible to buy electrical screws from online retailers like Amazon. Often, you’ll see more options for sizes and materials, and packages will be sold in larger bulk quantities online. The only downside with ordering screws online is waiting for delivery, which can be problematic if you are in the middle of an active project.

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Related Questions

Can I use plastic screws in electrical boxes?

Screws are versatile, and there are many materials they can be made of. Usually, screws are metal, but sometimes plastic screws are made for specialized applications. Remember, though, that plastic screws may not have the rigidity and longevity as metal screws. They also may not be able to support as much weight compared to metal screws.

How Much Weight Can an Electrical Box Screw Hold?

Determining how much weight your screws can be essential to ensure your electrical box is held securely and safely. Usually, a 6-32 electrical screw can support about 12 pounds. For larger or heavier applications, you may need to use multiple electrical screws to support the weight.

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Upgraded Home Team
Upgraded Home Team

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