Induction Hob Installation: Electrical Requirements, Cut-Outs and Safety

Quick Answer: Induction hobs typically require a dedicated 32A or 40A circuit on a 6mm² cable, with a double-pole isolation switch within 2m of the hob but out of arm's reach from the cooking surface. The circuit is Part P notifiable work requiring a registered electrician or Building Control approval. The worktop cut-out must match the hob manufacturer's specified dimensions exactly — induction hobs have 3–5mm clearance tolerances and incorrect cut-outs cannot be remedied by shimming.

Summary

Induction hobs are now the dominant new installation choice in UK kitchens. They are faster to heat than ceramic, faster than gas, and far easier to clean. They also have the highest electrical demand of any domestic cooking appliance — a 4-zone induction hob at full power draws 7–14 kW, requiring a dedicated circuit that many older UK homes don't have.

The electrical installation is the critical constraint. For a like-for-like replacement of an existing induction or ceramic hob, the existing circuit may be sufficient; for a new installation, or where the hob wattage has increased, an electrician must assess the circuit and potentially upgrade the supply. This work involves both Part P notification and coordination with the kitchen fitter for the worktop cut-out timing.

Kitchen fitters should understand the electrical requirements well enough to identify potential problems early, coordinate with the electrician, and advise clients when their planned hob spec requires an electrical upgrade.

Key Facts

Quick Reference Table — Circuit Sizing by Hob Rating

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Hob Rated Power Required Fuse/MCB Min Cable Size Notes
Up to 7.2 kW 32A 6mm² T&E Standard domestic; most common
7.2–9.6 kW 40A 6mm² T&E Check voltage drop for longer runs
9.6–11.0 kW 45A 10mm² T&E High-performance hobs
11.0–14.4 kW 50A 10mm² T&E Full-width induction ranges
Single induction plate 13A Spur from ring Some small plates are plug-in; check

Detailed Guidance

Electrical Circuit Requirements

An induction hob must have a dedicated radial circuit — it cannot be connected to the ring final circuit with other sockets. The circuit runs from the consumer unit to the cooker control unit (CCP) and then to the hob connection point.

Circuit design (BS 7671:2018+A2:2022):

  1. Calculate the load current: I = P/V = (kW × 1000) / 230 = A
  2. Allow for the diversity factor: for a single hob, use 100% of rated current; for a range cooker with hob, oven, and grill, use a maximum demand diversity per BS 7671 Table 4A of Appendix 4
  3. Select cable cross-section to carry the current without exceeding the maximum operating temperature; 6mm² T&E has a current-carrying capacity of 32–46A depending on installation method (clipped direct, in conduit, in wall)
  4. Verify voltage drop: maximum 11.5V at 230V supply (3%) for a cooker circuit; for a 20m run at 32A in 6mm², V-drop = 32 × 20 × 7.3mV/A/m ÷ 1000 = 4.67V — within limit

Cooker control unit — this is the double-pole switch (45A or 50A) with an indicator neon. It provides local isolation within sight of the hob. Positioned at eye level on the wall adjacent to the hob, but NOT directly above the cooking surface (reaching across a hot hob to operate a switch is a fire/burn hazard). Some kitchen designs position the CCP on the wall to the side of the run rather than behind.

RCBO vs MCB — BS 7671 Amendment 2 requires RCD protection for circuits in kitchens (special locations); an RCBO (combined MCB + RCD) in the consumer unit provides this. An existing Type B MCB without RCD does not comply with current regulations for a new installation.

Worktop Cut-Out Requirements

The hob installation starts with the worktop cut-out. Critical steps:

  1. Obtain the installation guide before cutting — every manufacturer specifies slightly different dimensions; do not rely on standard dimensions
  2. Mark the cut-out position — typically centred on the cooking zone, with any specified offset from the back edge (most hobs need 50–100mm clearance from the back edge to allow the connection cable and ventilation)
  3. Mark and check clearances — verify the specified side clearances to the adjacent worktop edge or upstand; most induction hobs need 5–15mm each side
  4. Cut method — use a jigsaw with a fine-tooth blade for laminate; a circular saw or router jig for a cleaner laminate cut; stone/quartz/Dekton cut-outs must be cut by the fabricator during fabrication — do not attempt to cut stone with a jigsaw on site
  5. Seal cut edges — apply iron-on edge strip or silicone sealant to any laminate cut edge to prevent moisture ingress
  6. Test the fit — place the hob dry before connecting anything; check it sits flush with no rocking and the specified clearances are met

Under-counter clearance — the hob frame sits in the worktop and the underside of the hob extends below the worktop into the cabinet. Most induction hobs need 50–80mm of free air space below the unit for ventilation and electronics cooling. Check that no drawer or shelf is positioned directly under the hob. Some hobs have forced-air cooling fans internally — the hot exhaust air exits through vents in the hob frame into the underside of the worktop; this is normal.

Connection and Commissioning

After the circuit has been installed and tested by the electrician:

  1. Lay the hob into the cut-out and route the connection cable to the CCP
  2. Connect to the CCP using the appropriate terminal block (flex outlet plate or direct hob cable)
  3. Switch on at the consumer unit and CCP; the hob display should illuminate
  4. Test each zone with an induction-compatible pan; zone indicator lights confirm detection
  5. Test the boost function on each zone briefly; listen for unusual sounds
  6. Confirm isolation: switch off at CCP, confirm hob display goes dark and cannot be operated

Leave the client with the installation guide, confirm they are aware of the induction cookware requirement, and ensure they know the location of the CCP for isolation.

Adjacent Appliance Clearances

Near gas pipework — induction hobs have no requirement for gas exclusion zones (unlike gas hobs), but do not route gas pipework through the cabinet housing the electrical supply unless proper separation is maintained.

Near refrigeration — the heat emitted from an induction hob into the cabinet below is low compared to gas, but a fridge directly under an active hob still experiences elevated temperatures; maintain at least one cabinet width separation or consult the fridge manufacturer's installation requirements.

Integrated downdraft extract — some premium hobs integrate a pop-up extract unit within the hob frame. These are wired as a single unit but may require a larger combined cable; always check the installation guide.

Upgrading from Gas to Induction

Switching from gas to induction is an increasingly common project. Specific considerations:

  1. Gas pipe abandonment — the existing gas supply to the hob must be terminated by a Gas Safe engineer; the pipe must be capped at the nearest junction or converted to a permanent sealed end; do not simply leave a capped stub under the hob
  2. New electrical circuit — a gas hob position typically has only a 13A socket for ignition; a full 32–45A circuit must be installed
  3. Worktop — gas hob cut-outs are typically larger (for pan supports and burner bowls); the induction cut-out may be a different size, which means the worktop may need replacing; quote for both scenarios when pricing the job
  4. Gas cooker control unit — if there is an existing electrical cooker control unit for a separate oven, check whether the circuit rating is adequate for the induction hob

Frequently Asked Questions

Does an induction hob need a separate circuit from the oven?

Yes, in most cases. If a range cooker (hob and oven in one unit) is being replaced with a separate hob and oven, the oven can often share the same circuit (using the diversity rules in BS 7671). But where a standalone induction hob is being installed alongside an existing separate oven already on a shared circuit, you need to calculate whether the combined load exceeds the circuit capacity.

Can an induction hob be plug-in rather than hardwired?

Small single-zone induction plates (1.2–3.0 kW) are available as plug-in units and do not require a dedicated circuit or Part P notification — they plug into a standard 13A socket. Full-size multi-zone induction hobs are hardwired only. Do not attempt to use a 13A plug-in adapter for a full-size hob; the current draw far exceeds the fuse rating.

My new induction hob is wider than the old one. Can I extend the worktop cut-out?

In laminate: yes, carefully, using a jigsaw. The cut edges must be sealed. In quartz or granite: no, without cutting the stone. If the new hob is significantly larger, the worktop will likely need to be replaced. Get the exact hob dimensions before ordering stone, and confirm compatibility with the fabricator at the template stage.

Regulations & Standards