What is the minimum screw size required to secure equipment weighing 6 lb to a box?

To determine the minimum screw size required to secure equipment weighing 6 pounds to a box, it is essential to refer to the National Electrical Code (NEC) guidelines, specifically regarding the mechanical strength needed for support. The NEC specifies that a minimum screw size of No. 6 is adequate for supporting equipment that falls within the specified weight range.

Using a No. 6 screw provides sufficient strength to securely anchor the equipment while also considering factors such as material and application. A No. 6 screw is commonly used in electrical work for securing devices to boxes, as it strikes a balance between strength and manageability. Larger screws such as No. 8 or No. 10 may offer additional strength, but they are not necessary for the 6 lb weight. Conversely, a No. 4 screw may lack the required holding strength for the specified weight.

When selecting fasteners, it's crucial to ensure that they're sized appropriately not only for the weight but also for the type of material they are securing into, thus ensuring safety and compliance with industry standards. Therefore, a No. 6 screw is deemed the minimum acceptable size for this application, making it the correct choice.