Switch Plate Screws:
Switch plate screws are generally 6-32 (thread diameter of #6 and 32 threads per inch). Our metal screws have a countersunk angle of 82. Depending on the device you are covering, you'll need different lengths of screws to hold your cover plate in place.
5/16" (rocker, Despard, vintage low voltage) for strap mount plates
1/2" (toggle, duplex, blank, simplex) for box or device mount plates
UNC (Unified Course Threads) Threads According to ANSI B1.1
6-32 screw diameter oval head: #6 equals .138" (9/64" or a little over 1/8", 3.505 mm). The pitch of the screw head is 0.794" and diameter is 1/4". This is used in the majority of electrical handy or masonry boxes.
8-32 screw diameter flat head: #8 equals .164" (a little over 5/32", 4.166 mm). The pitch of the screw head is 0.794" and diameter is 19/64". This larger size is used for diagonal screws in 4x4 square boxes, 1900 boxes, round or octagon boxes when mounting mudrings, etc. It requires a 0.18" close hole clearance which is slightly small than standard switch plate hole clearance of 0.19".
10-32 screw diameter flat head: #10 equals .1875" (3/16", 4.76 mm). The pitch of the screw head is 0.794" and diameter is typically 0.357" - 0.373". This is often used for mounting ceiling fans or other heavy items. It requires a 0.206" close hole clearance which is slightly larger than standard switch plate hole clearance of 0.19".
Types of Screws:
Screws can have a flat, round oval or pan head that's Phillips, slotted, combination or tamper-proof. They can also be self-tapping, which means they can tap their own hole as they are driven in, eliminating the need to first drill a hole in your material.
1. Phillips/slotted combination pan head screw: This is an example of the type of screw used to mount an electrical device into a handy box. Note that the bottom of the screw is tapered. This is an example of a self-tapping screw.
2. Phillips flat head screw: Flat head electrical screws are for use where the screw's head must be flush with the final surface.
3. Slotted flat head screw: Another example of a flat head screw, but made for a slotted screwdriver rather than Phillips.
4. Slotted oval head screw: Standard switch plate screws like this and are typically 5/16" or 1/2" in length.
5. Round slotted head screw: Used in specialty plates without round screw holes, such as these dryer outlet covers.
6. Plastic slotted screw: Plastic screws can be used to mount switch plates when heat transfer from metal screws may cause plastic plates to warp.
7. Spanner head screw: Special tamper proof screws that requires a special screwdriver to screw and unscrew.
8. Rosette head screw: Another type of fancy tamperproof screw used with a specialized screwdriver for installation.
How to Measure Wall Plate Screws
1/4" Screws (Nominal)
Quarter inch screws for light switch plates have a 5/16" length without the screw head.
The length, including the standard slotted oval head, is 5/16", although the length can vary +/- a 1/16".
These shortest wall plate screws are the standard for covers with strap mount screw spacing, such as Decora rocker plates.
1/2" Screws
Half inch screws can be measured including the screw head.
This size is the standard for device mount and box mount covers.