Cooker Control Units and Cooker Switches — 45A DP, Metal Clad, and Cooker Hood Connections for UK Electricians

Cooker circuit wiring is one of the most common domestic installation jobs for Part P qualified electricians. Every electric cooker, range, and built-in oven requires a dedicated radial circuit protected by a 32A or 40A MCB, terminated at a 45A double pole (DP) cooker control unit within 2 metres of the appliance. Getting the right switch type — whether a standalone cooker switch, a control unit with 13A socket, or a metal clad version for a kitchen peninsula — determines both compliance and customer satisfaction.

This guide covers cooker switch selection, wiring requirements under BS 7671:2018+A2:2022, circuit protection, cooker hood connections, and how to choose between white, metal clad, and grid module formats.

What Is a Cooker Control Unit?

A cooker control unit (CCU) is a switched fused unit that provides a local isolation point for an electric cooker or range. Under BS 7671 Regulation 537.3, every fixed appliance with a rated current exceeding 13A must have a local means of isolation within sight of the appliance or capable of being locked off. The 45A DP switch in a CCU satisfies this requirement.

Cooker control units come in two main configurations:

• Cooker switch only — 45A DP switch in a single or double gang plate, no socket
• Cooker control unit with 13A socket — 45A switch plus a standard switched socket for small appliance flex, the most common domestic fitting

The 13A socket in a CCU is a convenience outlet for a kettle or toaster — but note that BS 7671 Regulation 553.1.7 prohibits placing a 13A socket within 300mm of a sink or in Zone 1/2 of a kitchen splashback area. Always position the CCU at least 300mm from the sink and on an accessible section of wall, not directly behind the hob.

Circuit Requirements for Cooker Installations

A standard domestic electric cooker circuit must meet the following minimum requirements under BS 7671:2018+A2:2022:

• Circuit protection: 32A MCB (Type B) for cookers up to 8kW demand, or 40A MCB for ranges and combination ovens up to 10kW. Most free-standing electric cookers have a declared diversity demand of 10A + 30% of remaining load — check the appliance nameplate
• Cable: 6mm² twin and earth (6243Y) for 32A circuits; 10mm² for 40A circuits run in thermal insulation. Cable must be clipped, trunked, or chased — not run loose
• RCD protection: Required for all circuits under 18th Edition Amendment 2 (2022). The consumer unit should have dual RCD or RCBO protection on the cooker circuit. Where the cooker circuit has metallic enclosure and is on a TN-C-S (PME) supply, an SPD may also be required
• Circuit length: Voltage drop must not exceed 5% (11.5V for 230V supply). For 6mm² at 32A, maximum cable length is approximately 22 metres — adequate for most domestic kitchens
• Switch rating: 45A minimum for all cooker connections. Never use a 20A DP switch on a cooker circuit — it is not rated for the continuous current demand

Choosing a Cooker Switch: White vs Metal Clad

For most domestic kitchens with standard plaster walls, a white plastic cooker control unit is the standard specification. Where the CCU is in an exposed position, a commercial kitchen, or a utility room with condensation risk, metal clad (steel) versions offer superior durability and a cleaner industrial aesthetic.

White Plastic CCUs — MK Logic Plus Range

The MK Logic Plus range is the most widely specified CCU in UK domestic installations. MK (now part of Honeywell) manufacture to BS EN 60669-1 with silver-plated contacts rated for 45A continuous operation. The Logic Plus design uses a single gang plate for the switch module and a separate socket outlet, giving a clean low-profile appearance.

For a standard kitchen installation where the CCU will be surface-mounted on a standard 35mm back box, the MK 45A Double Pole Cooker Control Unit with 13A Switched Socket (M1811) is the specification choice. The neon indicator confirms isolation — essential for compliance with the local isolation requirement in Regulation 537.3.1. The Logic Plus M1811 fits a standard 2-gang 35mm back box and suits kitchens with white or cream fitted units.

Where the circuit demand requires a 50A rated switch (typically where the installer is using a 40A MCB for a large range), the 50A Double Pole Cooker Switch with Neon (Logic Plus Range) provides the additional headroom. This 2-gang variant includes the switch only — no 13A socket — making it suitable for built-under double ovens where the socket convenience outlet would be inaccessible behind kitchen furniture.

Metal Clad CCUs — Knightsbridge

For utility rooms, boot rooms, and exposed wall positions, the Knightsbridge Metal Clad 2G 45A DP Cooker Switch with 13A Switched Socket and Neons offers a robust alternative at a lower price point. The brushed steel faceplate resists scuffs and marks better than white plastic in working environments, and the dual neons (one for the switch, one for the socket) give clear status indication. This unit mounts on a standard 2-gang 35mm metal back box.

Metal clad units are also the correct specification for garages and outbuildings where the CCU might be exposed to dust or occasional moisture — provided the installation is not in a zone requiring IP-rated equipment (IP2X minimum for Zone 2 of a bathroom, which is outside the kitchen specification).

Cooker Hood Connections: 20A DP Grid Switch

A cooker hood (extractor fan above a hob) is separately wired on its own circuit, typically a 20A radial from a 20A MCB in the consumer unit, using 2.5mm² twin and earth cable. The hood must have a local isolation switch within sight — this is where the cooker hood grid switch is used.

The MK 20A DP 1-Way Grid Cooker Hood Switch is a grid module designed to fit into the MK Masterseal or K-series grid system. Grid modules allow a single plate to carry multiple functions — a 20A hood switch, a 13A switched socket, and a TV co-ax outlet all in one flush plate, which is common in modern kitchen peninsula layouts.

When specifying a cooker hood grid switch, note that:

• 20A DP is appropriate for hoods up to 4kW (all domestic hoods fall within this)
• The switch must be double pole to satisfy the isolation requirement
• Grid systems require a grid plate (purchased separately) and a 2-gang or 3-gang flush back box
• For simultaneous cooker + hood isolation, a twin plate carrying both a 45A CCU and a 20A grid module in a 3-gang back box is a common approach — verify back box depth (minimum 47mm) to accommodate the bulkier 45A switch

Wiring a Cooker Control Unit: Step-by-Step

Cooker CCU wiring follows a simple arrangement, but correct termination is safety-critical. Work is notifiable under Part P of the Building Regulations in England and Wales unless the installer holds a self-certification scheme membership (e.g. NICEIC, NAPIT).

1. Isolate at consumer unit — lock off the MCB protecting the cooker circuit and confirm isolation with a voltage indicator (GS38-compliant). Never rely on the CCU switch itself to isolate before first connection
2. Feed cable into back box — the 6mm² or 10mm² radial from the consumer unit enters the back box through a rubber grommet. Ensure the cable is adequately supported within 150mm of the back box entry
3. Cooker flex cable — the 4mm² (minimum) flex from the cooker enters a second knock-out. Many electricians prefer to run the appliance flex directly into a junction box behind the cooker rather than through the CCU, to allow easy appliance removal without exposing live terminals
4. Terminations in the CCU: Line (brown) to switch terminal L1, Neutral (blue) to N terminal, Earth (green/yellow) to earth terminal on both feed and load sides. The load terminals connect to the cooker flex. The 13A socket (where fitted) is connected in parallel with the feed side, not the load side — the socket is always live when the mains feed is connected, regardless of the 45A switch position
5. Continuity and insulation resistance — before reinstatement, verify R1+R2 continuity of the earth path and insulation resistance between conductors (minimum 1MΩ at 500V DC)
6. Test and notify — complete an EIC (Electrical Installation Certificate) for the new circuit. Self-certify via scheme membership or notify the local building control authority

Fault-Finding: Common Cooker CCU Issues

Cooker control units are generally reliable, but two common faults present during service calls:

• Neon fails but switch operates correctly: The neon indicator in CCUs is a simple 240V neon with a current-limiting resistor. Over 10–15 years, the neon element fails. This is a cosmetic fault — the unit continues to operate safely. Replace the CCU to restore the neon function, as the neon is not field-replaceable in most units
• Switch makes but cooker does not power up: Check the 13A socket outlet — it is sometimes confused with the main 45A cooker terminals. Verify with a multimeter that load terminals L and N are both live when the switch is on. If not, the switch contacts have failed (unusual but occurs after many decades of use). Replace the CCU
• Cooker trips RCD on startup: This is most commonly a fault within the cooker itself (heater element leakage to earth), not the CCU. Test with the cooker disconnected from the CCU. If the RCD holds without the cooker connected, fault is in the appliance

Related Products and Cross-Links

Cooker installations are often combined with other kitchen wiring work. Related products at APM Electricals include:

• Fused Connection Units (FCUs) — for cooker hood and washing machine connections where a direct flex from consumer unit is not practical
• 13A Switched Sockets — for supplementary kitchen socket outlets
• Metal Back Boxes and Dry Lining Boxes — 47mm depth required for 45A CCUs
• Consumer Units — for RCBO-protected cooker circuits meeting 18th Edition Amendment 2
• Dimmer Switches — leading edge, trailing edge, and LED compatibility for kitchen lighting circuits

Summary

For most domestic cooker installations, the MK 45A DP Cooker Control Unit with 13A Socket (M1811) is the standard specification. For exposed or utility locations, the Knightsbridge Metal Clad 2G 45A DP unit provides equivalent compliance at lower cost. For large ranges and 40A circuits, step up to the 50A MK unit. Cooker hood circuits use a dedicated 20A DP grid switch module. All cooker circuits require RCD protection under BS 7671:2018+A2:2022 Amendment 2, and the installation is notifiable under Part P.

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