Light Switches — 1-Way, 2-Way, Intermediate, and Metal Clad Wiring Accessories for UK Electricians

Light switches are the most frequently installed wiring accessory on any domestic or commercial electrical job. Whether you're fitting a single one-way switch in a bedroom, wiring a two-way circuit for a staircase, or running metal clad accessories in a garage or outbuilding, selecting the right switch and wiring it correctly saves time and ensures compliance with BS 7671 and BS EN 60669.

This guide covers the switch types UK electricians encounter most, explains one-way, two-way, and intermediate wiring configurations, and recommends stocked APM products for the core scenarios.

Switch Rating: What 10AX Means

Most domestic light switches are rated 10AX — 10 amps resistive. The "X" suffix (from BS EN 60669) indicates the switch is rated to break inductive loads (fluorescent starters, motor loads) at full rated current, not just resistive lamp loads. For standard LED downlights and pendant fittings, a 10AX switch is suitable. For 20AX retractive switches used with mechanical bell pushes or 20A circuits, a higher-rated module is required.

Key ratings you'll see on site:

• 10AX — standard domestic, suitable for LED, halogen, incandescent
• 20AX — retractive/momentary switches, heavy-duty or commercial
• 6A — older or budget accessories (check before fitting on circuits with multiple downlights)

1-Way vs 2-Way Switches: The Practical Difference

A 1-way switch has two terminals (L1 and COM) and controls a light from a single position. This is correct for a room with one switch point — a bedroom, utility room, or single-access space.

A 2-way switch has three terminals (COM, L1, L2) and is designed for circuits where a light is controlled from two locations — the top and bottom of a staircase, or both ends of a corridor. Both switches in the circuit must be 2-way. The wiring uses a 3-core and earth cable (grey, black/brown, blue) between the two switch positions.

In practice, many electricians fit 2-way switches everywhere, even in single-switch positions, because it costs almost nothing extra and means you're not stocking two types.

Intermediate Switches

When a light circuit requires three or more switch positions — a long corridor with three entrances, a large room with multiple doors — intermediate switches are inserted between the two 2-way switches at each end. An intermediate switch has four terminals and crosses or connects the two traveller wires depending on its position.

The wiring configuration is: 2-way switch → intermediate switch(es) → 2-way switch. Each intermediate switch adds one more control point. BS 7671 Appendix 6 contains the standard switch wiring diagrams.

Single Gang, Double Gang, and Multi-Gang

Gang refers to the number of switch rockers on a single faceplate:

• 1-gang (1G) — one rocker; controls one circuit
• 2-gang (2G) — two rockers on one plate; controls two circuits from a single back box
• 3-gang, 4-gang, 6-gang — used where multiple lighting circuits need control from one point (open-plan, commercial, garden circuits)

Multi-gang switches reduce the number of back boxes required. A 3-gang 2-way switch in a kitchen controls worktop lights, pendant, and extractor fan isolator from a single 35mm single-gang back box with suitable grid wiring.

White Plastic vs Metal Clad

White plastic (polycarbonate) accessories are standard for domestic interiors — living rooms, bedrooms, hallways. They're fast to install, widely available, and accepted under most Part P works without additional specification.

Metal clad (grey pressed steel) accessories are required or preferred in:

• Garages, workshops, and outbuildings
• Commercial kitchens and catering areas
• Utility rooms and plant rooms
• Surface-wired conduit installations
• Any location where mechanical protection is needed

Metal clad switches have a higher impact rating and are surface-mounted directly to conduit boxes or Kavakos style metal surface boxes. They do not require a separate back box in surface wiring — the metal switch plate itself sits on the wall or conduit system.

Screwless Flat Plate and Designer Styles

For higher-specification domestic work — kitchens, bathrooms (outside zones), reception rooms — screwless flat plate switches in brushed chrome, polished chrome, or matt black offer a cleaner finish. These use a separate cover plate that clips over the module without visible screws. They require slightly deeper back boxes (35mm minimum) for the wiring connections.

Knightsbridge, Hamilton, and BG Nexus all produce flat-plate ranges compatible with standard back box sizes and standard 10AX switch modules.

Wiring a 2-Way Staircase Circuit

The most common multi-switch wiring task on domestic jobs:

1. Run 1.0mm² or 1.5mm² twin and earth from the consumer unit lighting circuit to the first switch (downstairs)
2. Run 1.0mm² 3-core and earth between the two switch positions as the "strapping" cable
3. Connect COM terminals to the feed/return at each switch; L1 and L2 carry the two traveller wires between them
4. Connect the lamp in the ceiling between the switched live return from the upstairs switch and neutral

Old notation used red/yellow/blue for 3-core; new installations use brown/black/grey (the "harmonised" colours introduced in 2004 and mandatory from 2006). When extending old circuits, add appropriate identification sleeving.

Part P and Notification

Like-for-like replacement of a switch (same position, same circuit, no new cable) is exempt from Part P notification in England. New switch positions, new circuits, or work in kitchens and bathrooms (special locations) require notification to building control or a competent person scheme (NICEIC, NAPIT, ELECSA). Always issue a Minor Works Certificate for like-for-like and an Electrical Installation Certificate for new circuits.

Recommended Products

The four switch types APM stocks cover the majority of domestic jobs:

Thrion 1G 2-Way 10AX Slimline White Switch

Handle: 1g-2way-10ax-switch | Price: £1.60

Entry-level 10AX 2-way switch for standard domestic circuits. Slim profile, standard back box fit, white finish. Suitable for bedrooms, hallways, and secondary switch positions where budget is the priority. 2-way rated so compatible with staircase and corridor circuits.

Click Curva 10AX 1G 2-Way Plate Switch

Handle: click-1-gang-2-way-10a-plate-switch | Price: £2.20

Mid-range 10AX single-gang 2-way switch from Click's Curva range. Curved-edge faceplate, positive rocker action, standard screw terminals. Suitable for main domestic switch positions in living rooms, bedrooms, and hallways. Compatible with standard 25mm single-gang back boxes.

Click Curva 10AX 2G 2-Way Plate Switch

Handle: click-2-gang-2-way-10a | Price: £2.99

Double-gang 2-way plate switch for controlling two lighting circuits from one position — ideal for kitchen worktop lights + pendant, or living room + hall. Same Curva curved-edge faceplate as the single gang. Sits on a standard 2G back box (35mm). Reduces number of back boxes on multi-circuit boards.

Knightsbridge Metal Clad 10AX 1G 2-Way Switch

Handle: metal-clad-10ax-1g-2-way-switch | Price: £5.20

Surface-mount metal clad switch for garages, workshops, outbuildings, and any surface-wired installation. 10AX 2-way rated. Grey pressed steel body with earth connection. Designed for use with 20mm conduit surface boxes or direct to masonry. Mechanical impact resistance far exceeds plastic accessories — correct specification for any area subject to knocks or damp environments.

Summary

Light switches appear on every job. Stocking a range of 1G and 2G 2-way switches in both white plastic and metal clad ensures you can handle any domestic circuit without a trip to the merchant. Budget white switches work for rental and volume domestic; Click Curva covers the mainstream; metal clad is the correct choice for surface wiring, garages, and commercial premises.

Related articles: #223 Wiring Accessories | #274 13A Sockets | #275 Dimmer Switches | #271 FCUs | #262 Metal Back Boxes