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Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Clear out junk files and repair common Windows errorsFree Scan →For bonding an equipment grounding conductor to a metal electrical box under the U.S. National Electrical Code (NEC), use a grounding screw that is reserved for grounding, a grounding device listed for the purpose, or equipment listed for grounding. NEC 250.148(C) sets that requirement. A common manufacturer-specified option is a green 10-32 x 3/8-inch grounding screw, but only when the box has a matching tapped 10-32 hole. Green color alone does not qualify an ordinary screw. The sections below explain how to confirm a suitable fastener, what to do when the box has no grounding hole, and where a device’s own grounding screw fits in.
What the code requires for a metal box
NEC 250.148(C) addresses metal boxes directly. It states that a connection shall be made between the equipment grounding conductor(s) and the metal box “by means of a grounding screw that shall be used for no other purpose, equipment listed for grounding, or a listed grounding device.” The text reproduced in the source material is the 2020 edition. Your jurisdiction may have adopted a different edition, with local amendments, so confirm the wording in the edition your inspector enforces.
Three options follow from that sentence:
- A grounding screw used for no other purpose. The screw is dedicated to bonding. It is not a mounting screw for a cover, plate, or bracket that is also used to bond the box.
- Equipment listed for grounding. The equipment carries a listing that covers its grounding function.
- A listed grounding device. A clip, screw, or similar part with a listing for the box and application.
The broader connection rules in NEC 250.8 frame the same choice. The cited text lists machine screw-type fasteners that engage at least two threads or are secured with a nut, thread-forming machine screws that engage at least two threads in the enclosure, connections that are part of a listed assembly, and other listed means. That list describes acceptable connection methods. It does not authorize any screw in any box.
Matching the screw to the box
The most common purpose-made option is a green grounding screw sized to a tapped hole in the box. ABB/Steel City describes its GS1-SC as a green-finish, zinc-plated steel grounding screw, 10-32 x 3/8 inch, for boxes with a #10-32 tapped hole. Those are the manufacturer’s specifications for that product. They are not a universal fit for every metal box.
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- Ensures compliance with article 250 of the national electrical code
- Accommodates hundreds of different solid or stranded wire combinations
- Thread-forming, hole-finding tip10-32 screw provides a secure grip
- Designed for making ground connections and bonding non-metallic sheathed cables
- Convenient for device grounding applications
Before buying or installing one, check these items:
- Find the tapped hole. Look inside the box for a threaded hole marked for grounding, usually near the back or side wall. Note its thread size. Common sizes in the source material are 10-32 for boxes with a tapped grounding hole.
- Match the thread. A 10-32 screw should not be forced into a hole of another size. Cross-threading damages the box and the screw, and a damaged thread may not hold the bond.
- Check the length. The source’s example is 3/8 inch. Length should be enough to engage the threads fully without projecting into the wiring space or contacting conductors.
- Read the instructions. The manufacturer’s instructions govern the installation. They may specify torque, the box types covered, or the conductor arrangement.
- Use the screw for grounding only. Once it is dedicated to the bond, do not reuse it for a cover, plate, or device mount.
Green finish is a convention that identifies grounding hardware. It is not proof of suitability. Confirm the thread, the listing or intended use, and the instructions for the specific box.
Rank #2
- Large Quantity Supply: we want to make your work easier, and that's why we provide a package that contains 100 pieces of grounding screws; It's a long lasting supply of screws that saves you the trouble of having to stop and order screws, enhancing your overall productivity
- Quality Material: our ground wire screws are made with quality carbon steel with galvanization process, offering durability and resistance to corrosion; Coupled with an attractive green finish, high hardness and resistance to wear, these screws are designed to last and withstand the harsh environmental conditions
- Proper Size: each of the electrical box screws boasts a proper size with about 3/8 inches in length, and the number of threads is 10-32; The suitable size ensures you have a comfortable fit with easy installation, and it's suitable for a wide range of grounding applications
- Easy Installation: the bright green color makes them easy to recognize, and the user friendly design of our hex head outlet screws makes them straightforward and easy to install; You don't need professional skills, making it a convenient installation process for almost everyone; Simply wrap the grounding wire around the screw head and tighten, applied in electrical junction boxes to help provide a solid accessory
- Wide Applications: the junction box screws are made versatile and can be applied in various applications; Whether it's for commercial, industrial, or residential, these ground screws for electrical box will serve you accordingly; Hex washer head allows you to quickly and easily screw it into most threaded ground holes and box edges
When the box has no grounding hole
If the box does not have a matching tapped hole, do not substitute a standard machine screw and assume it is acceptable. Use one of these alternatives:
- A listed grounding device intended for that enclosure and application. Check the listing, the box material and thickness it covers, and its installation directions.
- A grounding clip or other listed hardware recommended by the box manufacturer for that model.
- A different, listed enclosure that already includes a tapped grounding point, if the existing box cannot take a listed device.
The option you choose depends on the box and the work. A listed device that fits the enclosure is the reliable path. Improvising a fastener is the failure mode to avoid.
Rank #3
- Bulk Supply: We are committed to making your work easier, and thus offer a package of 100 grounding screws per set. A long-lasting and stable supply enables you to replenish goods frequently without interrupting work, effectively enhancing overall work efficiency.
- Premium Material: The grounding screw is made of high-quality carbon steel and combined with galvanizing process, featuring excellent durability and corrosion resistance. With an attractive green coating treatment, it features high hardness and wear resistance, capable of withstanding harsh environmental tests and ensuring a long service life.
- Precise Dimensions: The length of each screw in the electrical box is accurate to 3/8 inches, with thread specifications ranging from 10 to 32. The just-right size design ensures a perfect fit during installation, simplifies the installation process, and is suitable for a variety of grounding application scenarios.
- Easy Installation: The bright green appearance makes it easy to identify quickly. The hexagonal head design makes the installation of socket screws intuitive and simple. No professional skills are required. Ordinary people can easily complete the installation - just wrap the grounding wire around the screw head and tighten it, and a firm connection can be provided in the electrical junction box.
- Wide Application: These junction box screws feature multi-functional characteristics and can be flexibly applied in commercial, industrial and residential fields. The hexagonal washer head is designed to be quickly screwed into the vast majority of threaded grounding holes and the edges of the box, meeting diverse grounding requirements.
Grounding screws with a pigtail
Sometimes the box needs a short conductor from the grounding screw to the device, such as a receptacle’s grounding terminal. In that case, a grounding screw with a pigtail can be used where appropriate. ABB/Steel City’s GSB12 listing describes a 10-32 screw with a six-inch, solid copper #12 AWG bare pigtail. That product’s conductor size is a manufacturer specification. It does not decide the conductor size for your circuit. Determine conductor sizing and connection method from the applicable code and the installation details.
A device’s grounding screw is a different part
The grounding terminal on a receptacle or switch is for the device’s own equipment grounding conductor. It is not the screw that bonds the metal box. A Leviton receptacle product page lists a brass 8-32 grounding screw for that particular model. That is a device specification, and it does not describe a general box screw. Do not treat a device’s terminal screw as the box bonding screw unless the device instructions or listing say it is designed for that use.
Rank #4
- Package Includes: This all-in-one hardware bundle contains 200PCS standard green ground screws and 1-piece 5*75mm cross screwdriver, fully covering daily repair, batch electrical wiring and long-term backup needs
- Premium Material: Built withcarbon steel and finished with professional electro-galvanized treatment, these ground screws electrical feature high hardness, strong pressure resistance and smooth uniform surface. The fine galvanized outer layer strengthens overall structural stability, resisting daily oxidation and environmental wear. Sturdy and not easy to deform or snap under tightening force, serving as long-lastingground screw hardware for all indoor and outdoor electrical work
- Precision Thread Standard Size: Features precision machine-rolled threads with uniform pitch, ensuring tight locking connection, no slipping, no loosening after installation.10-32 x 3/8 ground screws size with burr-free smooth edges. Perfect fit for all standard mounting holes on electrical accessories, no forced assembly, no component damage, effectively improving overall wiring progress and working efficiency
- Easy to Install: Hex Phillips combo head design fits all common hand screwdrivers, power drills and impact drivers, offering truly effortless installation. The supporting 5*75mm screwdrivers holds firmly and rotates steadily, speeding up repeated fastening work. These reliable ground screws electrical box cut down working time greatly, ideal for professional electricians, maintenance crews and household DIY wiring installation
- Wide Application Scenarios: Practical universal design fits most common electrical connection scenarios, perfectly suitable for junction boxes, outlet boxes, switch boxes and standard equipment grounding fixation. Great for home circuit upkeep, factory equipment wiring, building construction grounding and regular hardware replacement. This kit provides indispensable ground screws foundation support for residential, commercial and industrial electrical installation tasks
Fastener length and wiring space
Fasteners that enter a box can contact conductors or insulation if they are too long or positioned poorly. Leviton’s reproduction of 2023 NEC 314.5 discusses screw type and limits on fasteners entering wiring spaces, including machine-type screws with blunt ends in certain circumstances. The exact limits depend on the enclosure and the subsection that applies. Check the code section for your edition rather than applying one dimension to every box.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Knockouts can affect bonding
If a box has concentric or eccentric knockouts, bonding continuity can depend on the knockout’s integrity. UL Solutions explains that a bonding jumper may be required where that integrity has been compromised. This is a separate bonding concern for the enclosure. It does not change the screw-selection rule, but it matters when a box has been modified or has damaged knockouts.
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- Large Quantity Supply: we want to make your work easier, and that's why we provide a package that contains 250 pieces of grounding screws; It's a long lasting supply of screws that saves you the trouble of having to stop and order screws, enhancing your overall productivity
- Quality Material: our ground wire screws are made with quality carbon steel with galvanization process, offering durability and resistance to corrosion; Coupled with an attractive green finish, high hardness and resistance to wear, these screws are designed to last and withstand the harsh environmental conditions
- Proper Size: each of the electrical box screws boasts a proper size with about 3/8 inches in length, and the number of threads is 10-32; The suitable size ensures you have a comfortable fit with easy installation, and it's suitable for a wide range of grounding applications
- Easy Installation: the bright green color makes them easy to recognize, and the user friendly design of our hex head outlet screws makes them straightforward and easy to install; You don't need professional skills, making it a convenient installation process for almost everyone; Simply wrap the grounding wire around the screw head and tighten, applied in electrical junction boxes to help provide a solid accessory
- Wide Applications: the junction box screws are made versatile and can be applied in various applications; Whether it's for commercial, industrial, or residential, these ground screws for electrical box will serve you accordingly; Hex washer head allows you to quickly and easily screw it into most threaded ground holes and box edges
Choosing among the options
| Option | When it fits | What to verify |
|---|---|---|
| Grounding screw (for example, a green 10-32 x 3/8-inch screw) | The metal box has a compatible tapped grounding hole | Thread size and length, dedicated grounding use, listing or approved application, manufacturer instructions |
| Listed grounding device or clip | The box has no suitable hole, or the manufacturer specifies a listed device for that enclosure | Listing, box material and thickness compatibility, installation directions |
| Grounding screw with pigtail | A short conductor from the box to a device is needed | Conductor size and type, connection method, box and device requirements |
| Device grounding terminal screw | Terminating the device’s own equipment grounding conductor | Device instructions. Not the box bonding screw unless the listing says so |
Practical limits of this guidance
This guidance reflects NEC-based practice and manufacturer examples in the United States. It does not establish which code edition or local amendments apply in your area, and it cannot resolve a particular box’s condition, bonding path, conductor gauge, or layout. Confirm those points with the enclosure and device instructions and with your local authority having jurisdiction.
Work on electrical equipment can expose energized conductors. Turn off power at the breaker, verify the circuit is de-energized with a tester, and bring in a qualified electrician if you are unsure of the bonding path or the box’s condition.
ABB/Steel City product pages support the specifications cited here. They do not establish availability at any retailer. Check the current catalog or a supplier for a part that matches the thread and length your box requires.
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