M3.5 x 75mm Raised Head Countersunk Electrical Screw - Nickel (100 Pack)

The Knightsbridge M3.5 x 75mm raised head countersunk electrical screw is a machine screw designed for fixing electrical accessories to UK back boxes and mounting frames. The 3.5mm diameter thread matches the standard mounting holes on UK faceplates, switches, sockets and modular accessories, while the 75mm length allows the screw to pass through the accessory, through the mounting frame, and into the back box lugs with enough thread engagement for a secure fixing.

The raised countersunk head sits flush with the faceplate surface when driven in, eliminating screw protrusion on wall-mounted accessories. The nickel finish provides corrosion resistance in typical indoor environments and matches polished chrome, brushed chrome and steel-finish faceplates. Sold in packs of 100, the quantity covers approximately 12-16 dual-gang accessories or 25-33 single-gang accessories depending on the number of mounting points per plate.

These screws are a direct replacement for the fixing screws supplied with Knightsbridge and most other UK electrical accessory ranges. The M3.5 thread is the UK standard for electrical accessory mounting, so these screws are compatible with back boxes, grid frames and mounting plates from all major UK manufacturers. The 75mm length is longer than the typical 40mm screw supplied with most accessories, making it suitable for deep back boxes, stacked mounting frames, or installations where additional mounting depth is needed.

Product Specification Sheet

What are these screws used for?

These screws fix electrical faceplates, switches and sockets to UK back boxes and mounting frames. The M3.5 thread is the UK standard for electrical accessory mounting, so they fit all major brands of UK electrical accessories.

Why would I need a 75mm screw instead of a standard 40mm screw?

The 75mm length is needed for deep back boxes, stacked modular grid frames, or installations where the accessory sits further from the wall surface. Most single accessories use 40mm screws, but 75mm screws are required when additional mounting depth is present.

How many screws are in a pack?

The pack contains 100 screws. This is enough to fix approximately 25-33 single-gang accessories or 12-16 dual-gang accessories, depending on the number of mounting points per faceplate.

Are these compatible with screwless faceplates?

No. Screwless faceplates use a separate sub-frame that fixes to the back box with screws, and then a cover plate clips onto that frame without screws. These screws would be used to fix the sub-frame to the back box, but the cover plate itself does not use screws.