Knightsbridge Double 35mm Pattress Box with Earth Terminal - White Square Edge

The Knightsbridge SN1800 is a double-gang 35mm surface-mounted pattress box in white thermoset resin, designed to house 2-gang switches, sockets or other wiring accessories where recessed back boxes cannot be fitted. The box includes a dedicated earth terminal with brass fixing lugs visible on the right-hand side of the interior, providing a secure earthing point for metal faceplates and metal-framed accessories.

This pattress box is intended for retrofit installations on solid walls, tiled surfaces, or areas where cutting into the wall is impractical or prohibited. Common applications include commercial fit-outs, heritage buildings with listed walls, and domestic installations on external walls where depth is limited. The 35mm depth accommodates standard wiring accessories without the bulk of deeper boxes, keeping the overall projection from the wall to approximately 50mm once a faceplate is fitted.

The white thermoset resin construction is more impact-resistant than standard plastic and carries anti-microbial properties tested to ISO 22196:2011, making it suitable for hospitality, healthcare and food preparation environments where surface hygiene matters. The square-edge profile matches the Knightsbridge Square Edge (SN) series of faceplates, giving a continuous outline between box and cover, but the box also accepts any standard double-gang accessory with 120mm fixing centres. The box measures 146mm wide, 86mm tall and projects 40mm from the wall, with pre-formed cable entry knockouts on the back and sides.

Product Specification Sheet

What is a pattress box used for?

A pattress box (also called a surface box or mounting box) provides a housing for switches, sockets and other wiring accessories when a recessed back box cannot be fitted into the wall. It surface-mounts directly onto the wall with screws or adhesive, allowing the accessory to be fitted on top without cutting into the plaster or masonry.

Does this fit standard 2-gang accessories?

Yes. The box has standard 120mm horizontal fixing centres and accepts any double-gang switch, socket or accessory designed for UK standard mounting. It pairs directly with Knightsbridge Square Edge (SN) series faceplates, but also works with any other manufacturer's 2-gang accessories.

What depth of accessory can it accommodate?

The 35mm internal depth accommodates most standard switches and sockets. Accessories with deep terminals or large cable bundles may need a 47mm pattress box instead. Check the accessory's required back box depth before ordering.

What are the anti-microbial properties?

The thermoset resin is treated with an anti-microbial additive tested to ISO 22196:2011, which inhibits bacterial growth on the surface. This makes the box suitable for healthcare, hospitality and food preparation areas where surface hygiene is monitored.