Surface Pattress & Drywall Boxes

About Surface Pattress & Drywall Boxes

Surface pattress and drywall boxes are essential electrical installation components that provide secure mounting points and protection for switches, sockets, and other electrical accessories. These enclosures ensure that wiring connections remain safe, accessible, and compliant with UK wiring regulations. Surface pattress boxes mount directly onto walls and are ideal for retrofitting installations or where chasing cables into walls isn't practical, whilst drywall boxes are specifically designed for hollow wall applications such as plasterboard and stud partitions.

The selection at Tooled-Up.com includes boxes in various depths, gang configurations, and materials to suit different installation scenarios. Single and double gang options are most common for domestic and light commercial work, whilst deeper boxes accommodate multiple cables or bulkier connection requirements. Modern boxes often feature quick-fix lugs, adjustable depth settings, and knockouts positioned for convenient cable entry from multiple directions.

Choosing between surface-mounted pattress boxes and cavity-fix drywall boxes depends largely on the wall construction and aesthetic requirements. Surface boxes offer straightforward installation without extensive wall preparation, making them popular for workshops, garages, and industrial settings where appearance is secondary to functionality. Drywall boxes provide a flush finish ideal for modern interiors, with spring-loaded or screw-fix mechanisms that grip the back of the plasterboard securely.

Jargon Buster

• Pattress Box: A surface-mounted electrical enclosure that sits proud of the wall surface, providing space for cable connections behind switches and sockets. Available in metal or plastic construction.
• Dry Lining Box: An electrical box designed specifically for installation in hollow walls and plasterboard partitions, using spring clips or screw-fix lugs to secure from within the cavity.
• Gang: Refers to the number of modules or switches/sockets that a box can accommodate. A single gang box accepts one module, whilst a double gang accepts two side-by-side.
• Knockout: Pre-formed sections in the box that can be removed to create cable entry points. These are typically positioned at various locations around the box perimeter.
• Box Depth: The measurement from the wall surface to the back of the box, determining how much space is available for cables and connections. Typical depths range from 16mm to 47mm.
• Earth Terminal: A dedicated connection point within the box for attaching the earth continuity conductor, essential for metal boxes to maintain electrical safety.

Who Uses Surface Pattress & Drywall Boxes?

• Electricians and Electrical Contractors: The primary users for new installations, rewiring projects, and electrical system upgrades in domestic, commercial, and industrial settings.
• Shopfitters and Shopfitting Companies: Installing electrical accessories throughout retail and commercial premises, often working with various wall constructions.
• Builders and Construction Professionals: Incorporating electrical infrastructure during new builds and renovation projects.
• Maintenance Engineers: Replacing damaged boxes and adding additional electrical points in existing properties and facilities.
• Facilities Managers: Overseeing electrical modifications and improvements in commercial buildings and industrial estates.
• Competent DIY Enthusiasts: Homeowners undertaking electrical work within the scope of permitted non-notifiable work, such as adding sockets on existing circuits.
• Interior Designers and Decorators: Specifying appropriate boxes for aesthetic installations where flush finishing is important.

How to Choose the Right Surface Pattress & Drywall Boxes

Wall Construction: Identify whether you're working with solid walls, hollow partitions, or plasterboard. Solid walls typically use surface-mounted pattress boxes or boxes that recess into chased-out sections. Hollow walls require drywall boxes with appropriate fixing mechanisms that grip from behind the board.

Gang Configuration: Determine how many switches or sockets need to be accommodated. Single gang boxes suit individual accessories, whilst double gang and larger configurations allow multiple modules side-by-side. Consider future requirements to avoid costly modifications later.

Box Depth: Assess the volume of cables and connections required. Shallow boxes (16-25mm) suit simple installations with minimal cables, whilst deeper boxes (35-47mm) provide space for multiple cables, connection blocks, or 240v accessories with deeper back profiles. Regulations require adequate space to avoid cable stress.

Material Selection: Metal pattress boxes offer superior fire resistance and mechanical strength, making them preferred for commercial installations and locations requiring extra durability. Plastic boxes are lightweight, cost-effective, and sufficient for most domestic applications. Metal boxes require proper earthing.

Fixing Method: For drywall installations, choose between spring-loaded clips that automatically grip when inserted, or screw-fix lugs that tighten against the back of the board. Tooled-Up stocks both types, with spring-loaded versions offering faster installation and screw-fix providing adjustable security.

Compliance and Standards: Ensure boxes meet BS EN 60670 standards and are suitable for 240v UK installations. Check that knockout arrangements and dimensions match your cable routing requirements and the faceplate accessories you intend to fit.

Popular Accessories

• Blanking Plates: Cover unused boxes neatly whilst maintaining accessibility for future use.
• Box Extension Rings: Increase the depth of existing boxes without complete replacement when additional space is required.
• Grommets and Bush Entries: Protect cables from sharp knockout edges and provide a professional finish to cable entries.
• Foam Acoustic Pads: Reduce sound transmission through hollow walls where electrical boxes penetrate between rooms.
• Cable Clips and Fixings: Secure cables neatly to the rear of surface boxes before connecting to accessories.
• Earth Tails and Terminals: Essential for metal box installations to maintain earth continuity throughout the installation.
• Spirit Levels and Laser Levels: Ensure accurate positioning and alignment of boxes, particularly important for multiple gang installations.

Safety Information

All electrical work must comply with BS 7671 (IEE Wiring Regulations) and Building Regulations Part P in England and Wales. Certain electrical work is notifiable and must be carried out by a qualified electrician registered with a competent person scheme. Always isolate circuits at the consumer unit before commencing any electrical work and verify isolation with an appropriate voltage tester.

Metal pattress boxes must be properly earthed to prevent them becoming live in fault conditions. Use appropriate cable entry methods to prevent damage to insulation and maintain IP ratings where required. Ensure adequate box depth to prevent cable stress and overheating—overfilled boxes present fire risks and contravene regulations.

When working with drywall boxes in hollow walls, be aware of hidden services including cables, pipes, and structural elements. Use a cable and pipe detector before drilling or cutting. In locations subject to moisture or outdoor conditions, use appropriately rated weatherproof enclosures rather than standard pattress or drywall boxes.

Frequently Asked Questions

What's the difference between a surface pattress box and a flush-mounted box?

A surface pattress box mounts directly onto the wall surface and sits proud, whilst a flush-mounted box recesses into the wall so the faceplate sits level with the wall surface. Surface boxes are easier to install as they don't require chasing out the wall, making them ideal for solid walls or retrofit situations. Flush boxes provide a neater appearance but require more installation work.

How deep should my electrical box be?

Box depth depends on the number of cables and the type of accessory being fitted. For simple installations with one or two cables, a 25mm box is often sufficient. However, 35mm or 47mm boxes are recommended for multiple cables or where 240v sockets with switches are being fitted, as these have deeper back profiles. Adequate depth prevents cable stress and ensures compliance with wiring regulations.

Can I use a drywall box in a solid wall?

No, drywall boxes are specifically designed for hollow walls and rely on spring clips or screw lugs that grip the back of plasterboard. For solid walls, you need either a surface-mounted pattress box or a flush box designed to be set into a chased recess and secured with screws and wall plugs.

Do plastic electrical boxes need to be earthed?

Plastic boxes themselves don't require earthing as they're non-conductive. However, the earth conductor must still be properly terminated—either connected directly to the earth terminal on a metal faceplate accessory, or connected via a dedicated earth terminal within the box if metal accessories are being used.

How do I secure a drywall box in plasterboard?

Cut an appropriate-sized hole in the plasterboard using the template often provided with the box. Insert the box into the hole, then either tighten the screw-fix lugs which pull against the back of the board, or simply push the box fully home if it has spring-loaded clips that automatically grip. Ensure the board is thick enough and in good condition to support the box securely.