Type 86 Recessed Electrical Wall Back Box – Switch & Socket Mounting Box with Wire Slots, 5pcs

Standard 86-type (86×86mm) recessed wall back boxes for switch and socket installation in residential and commercial buildings. The back box is embedded into the wall during construction or renovation — the switch or socket plate then mounts to the front of the back box using the two M4 fixing screws. Wire entry slots on all four sides and the rear allow cable routing from any direction. Available in white (for standard plasterboard/drywall installation) and blue (for concrete and masonry installation with additional fixing lugs).

Key Specifications

• Type: 86-type (86×86mm face, standard Chinese/European square format)
• Depth: 40mm (standard) or 50mm (deep, select above)
• Material: Flame-retardant ABS plastic
• Colors: White (plasterboard) / Blue (concrete/masonry)
• Fixing: M4 screw fixing for switch/socket plate
• Wire Entry: Knock-out slots on all four sides and rear
• Compatible Plates: All standard 86×86mm switch and socket plates
• Quantity: 5 pieces

86-Type vs 118-Type Back Boxes

• 86-type (86×86mm, this product): Square format. Standard in China, most of Europe, and countries following Chinese/European electrical standards. Accepts single-gang 86×86mm switch and socket plates. The most common back box format globally.
• 118-type (118×75mm): Rectangular format. Standard in Italy, Chile, Brazil, and countries following Italian electrical standards. Wider format accommodates multiple switch/socket modules side by side. Not interchangeable with 86-type.

White vs Blue Back Boxes

• White back box: For plasterboard (drywall) installation. Thinner walls, designed for cavity wall fixing with plasterboard fixing lugs or direct screw fixing into timber studs.
• Blue back box: For concrete and masonry installation. Thicker walls with additional fixing lugs for embedding in mortar or concrete. The blue color is a convention in Chinese electrical installation to distinguish masonry boxes from plasterboard boxes — not a functional difference.

Frequently Asked Questions

How deep should a back box be?

Standard depth is 35–40mm for most switches and sockets. Use a 50mm deep box when: (1) the cable has a large bend radius that requires more space behind the plate; (2) multiple cables enter the same box; (3) the switch or socket has a deep body (e.g., sockets with USB charging modules). Never use a back box shallower than the switch/socket body depth — the plate will not sit flush against the wall.

How do I install a back box in a plasterboard wall?

Mark the box position on the wall. Cut a rectangular hole slightly smaller than the box face using a drywall saw or oscillating tool. Feed the cable through the back box wire entry slot. Insert the box into the hole and secure with the plasterboard fixing lugs (expand the lugs behind the plasterboard by tightening the fixing screws). Connect the cable to the switch or socket, then screw the plate to the back box using the two M4 fixing screws.

Can I use a 86-type back box with a 118-type switch plate?

No. 86-type back boxes (86×86mm) are not compatible with 118-type switch plates (118×75mm). The fixing screw positions and box dimensions are different. Always match the back box type to the switch/socket plate type.

What cable size fits through the wire entry slots?

Standard wire entry slots accommodate cables up to approximately 16mm OD. For larger cables or conduit connections, knock out the larger entry points on the box sides. Most residential wiring cables (1.5mm² and 2.5mm² twin-and-earth) fit through standard slots without modification.

Typical Applications

• Residential: Switch and socket installation in new build and renovation projects
• Commercial: Office and retail switch/socket installation
• Renovation: Replacing damaged or undersized back boxes during switch/socket upgrades
• New construction: First-fix electrical installation before plastering

Package Contents

5 pieces — Type 86 recessed wall back boxes (color and depth as selected). Fixing screws included.