Combination Rotary Dimmers and Toggle Switches by Forbes & Lomax

The Combination Plate by Forbes & Lomax pairs rotary dimmers and toggle switches on a single plate, based on the elegant nickel and brass switches of the 1930s. Dimmers and toggles can be repositioned on the plate during installation.

Established in 1987, Forbes & Lomax is a UK-based heritage electrical brand recognized by architects and designers for refined switch and outlet design.

• Can I order this now? Yes, if your lights are standard dimmable LED, you know the plate type, and one of the six fixed layouts below suits your position. Standard means a line voltage bulb or fixture that dims on its own, with no driver, transformer or power supply in the run. If there is one, the module is chosen by that device rather than the fixture, so check Electrical & LED Compatibility below.
• Do I need to check anything first? Junction box depth, and that each device on the plate has its own circuit. A 4 gang plate needs four circuits behind it. Your electrician will know both.
• Does the Painted or Invisible plate need finishing? Yes. The Painted plate is painted and the Invisible inner plate is papered or painted, both before the electrician fits them. Allow for it in the schedule.
• When should I request a custom quote? Drivers, transformers, 0-10 V, any layout not listed below, or anything you are unsure about should be confirmed by our sales team in order to ensure compliance and compatibility. Please reach out to us at contact@cassonhardware.com.
• Can I install it myself? No. Line voltage, licensed electrician only.

Full specifications, module ratings and installation requirements are below.

The dimmer and switch mechanisms are identical across all three plates. What differs is how the plate meets the wall, which finishes are offered, and what has to happen on site before the electrician fits it.

Metal

• Construction: solid metal, finished by hand. Plate and mechanisms are supplied in the same finish.
• Site work: none. Fitted as supplied.
• Finishes: the full range. Aged Brass is the one exception, and applies to the plate only.

Invisible

• Top plate: transparent acrylic with bevelled edges, secured without visible fixing screws.
• Inner plate: primed aluminium, supplied ready to be papered or painted. Each unit ships with both plates.
• Wallpaper: the inner plate can be used as a template to cut a piece to fit.
• Over stone or tile: the inner plate can be faux painted to match the surrounding surface.
• Sequence: the inner plate is decorated as part of the wall finish, before the top plate goes on. Allow for it in the schedule rather than at handover.
• Finishes: applied to the toggle, knob and screws only. Aged Brass is not offered.

Painted

• Construction: etch-primed metal, supplied unpainted. The plate itself carries no metal finish.
• Method: lay the plate flat and apply two to three coats with a small roller. Rolling, hand-painting and spraying each give a different look.
• Top coat: a clear matte varnish can be applied to protect against marks.
• Glaze paint: undercoat the plate in the same colour as the walls.
• Sequence: paint the plate separately and let it dry completely before fitting. Screw heads can be painted to match and touched in afterwards.
• Finishes: applied to the toggle and knob only. Aged Brass is not offered.

Plate heights, widths and thicknesses are listed under Specifications below.

Each combination is a fixed layout. Dimmers and toggles can be repositioned on the plate during installation.

Toggles, rotary dimmers, push buttons and outlets can be mixed on the same plate, and multi-gang plates up to 8 gang are supplied to accommodate as many devices as required. Contact us with your device schedule for any layout not listed above.

Plate widths for each gang count are listed under Specifications below.

• Supply: line voltage, for conventionally wired installations.
• Toggle: 3-way, 15 A. Works as single pole or 3-way. 4-way available on request.
• Rotary dimmer: LED module only on this plate, max. 120 W LED or 300 W incandescent / halogen (TRIAC).
• Specialty modules: incandescent, magnetic low voltage and 0-10 V are available in every finish by request. They are needed only when a specific fixture calls for one, so they are not sold online.
• Minimum load: no formal minimum is stated for the LED module, though Forbes & Lomax recommend at least 5 W. Below that the dimmer may not register that a fixture is connected.
• Electronic low voltage: not supported. Forbes & Lomax do not make an ELV or reverse phase dimmer. Where a fixture requires one, a non-dimming toggle switch is the only option.

Dimming LED

Dimming LED is difficult across the whole lighting industry, not just this range. Compatibility can usually be predicted from a fixture's specification sheet, which is why we ask for it, but some trial and error is normal. Send your lighting schedule to contact@cassonhardware.com and we will review it with Forbes & Lomax.

• Guarantee: Forbes & Lomax cannot guarantee that every fixture labelled dimmable will dim satisfactorily on a TRIAC module. Performance depends on the make of fixture and the driver inside it.
• Minor flickering: even on a compatible fixture, some flickering can occur at the top or bottom of the range. Optimizing the dimming range resolves most of it.
• Bulb recommendation: for screw-in LED, Forbes & Lomax recommend Philips Ultra Definition. They dim smoothly to low levels and hold colour quality.
• Testing on site: where a fixture is unusual and you need certainty before committing to a full order, buy a single dimmer and test it in place.
• One lighting type per dimmer: recessed lights and a chandelier on the same dimmer will perform poorly even where each is individually compatible.

• Electrician: must be installed by a licensed electrician, in accordance with appropriate electrical codes and regulations.
• Circuits: each device on the plate is its own circuit. A 4 gang plate with two dimmers and two toggles needs four separate circuits behind it. Confirm the box and wiring support the layout before ordering.
• Circuit position: a dimmer can be wired at only one position on a 3-way or 4-way circuit. Every other position must be a non-dimming toggle.
• Junction box depth: recessed at least 1/8" below the finished wall surface. Refer to the Junction Box Assembly Diagrams below. Check existing boxes before ordering.
• Plate finishing: Painted and Invisible plates are decorated before the electrician fits them. Refer to Plate Overview above.
• Non-dimming: rotary switches are available on all three plates where a rotary style is wanted but only push on/off is required.
• Optimizing: the dimmer selects the correct dimming mode automatically once connected. Set the minimum and maximum levels for your fixtures, then apply the Program Lock. On a compatible fixture this resolves most flickering. Changing the mode by hand is a last resort, after optimizing has been tried.
• Momentary switches: not line voltage. They work only with home automation systems including Lutron Homeworks, Crestron, Savant, Vantage and Control 4.
• Areas of application: light-duty commercial, residential.

Layouts not listed above, and any circuit with a driver, transformer or 0-10 V dimming, are quoted by our sales team. Send the following to contact@cassonhardware.com and we will price it against your schedule.

• Plate type: Metal, Invisible or Painted
• Combination layout and gang count for each plate
• Fixture make and model on each dimmed circuit, and the driver or transformer type if there is one
• Total connected wattage per dimmer
• Number of switching positions on each circuit
• Fittings finish
• Junction box depth on site

Plate Sizes

All plates are 4.53" (115 mm) high. Metal and Painted plates are 1.8 mm thick. The Invisible plate is a 3 mm acrylic top plate over a 1 mm primed inner plate.

Device Dimensions

• Switch and knob: Ø 0.79" (20 mm).

Materials & Finishes

Fittings finish availability differs by plate. On the Metal plate the finish applies to the plate and mechanisms together; on Invisible and Painted it applies to the mechanisms only.

• Aged Brass: a plate finish only. Forbes & Lomax do not make Aged Brass mechanisms, so the toggle, knob and screws are supplied unlacquered brass and patina alongside the plate rather than matching on arrival.
• Living finishes: Unlacquered Polished Brass and Aged Brass darken and develop a patina with handling and exposure. This is intended and not a defect, and variation between pieces is normal.
• Lacquered finishes: Nickel Silver, Brushed Stainless Steel, Antique Bronze, Lacquered Brushed Brass and Matte Brass hold a consistent colour and will not change.
• Matte Brass: carries a baked lacquer coating that resists fingerprints.
• Care: wipe clean with a dry, non-abrasive microfiber cloth. Avoid chemical or alcohol-based cleaners.

• Toggle switches: conform to UL 20, certified to CSA C22.2 No. 111.
• Rotary dimmers: conform to UL 1472, certified to CSA C22.2 No. 184.

Review and ensure all certifications are applicable for your local code.

Product Sheets

• Rotary Dimmer Cut Sheet
• Toggle Switch Cut Sheet
• Painted Switch Range Cut Sheet
• Plate Dimensions
• Forbes & Lomax Brochure

Dimmer Documentation

• 120 W LED / 300 W Incandescent — Wiring
• 120 W LED — Optimization
• 120 W LED — Compatibility & Troubleshooting

Installation & Assembly

• General Instructions for Electricians (Switches & Dimmers)
• Toggle Switch Installation Instructions
• Junction Box Assembly Diagram (Rotary Dimmer)
• Junction Box Assembly Diagram (Toggle Switch)
• Invisible Plate Installation Notes
• Circuitry Visual Aid
• Home Automation Integration

Plates & Finishes

• Finish Swatches
• Custom Engraving
• Plate Cleaning Guidelines
• Sustainability Statement