Helpful video reference. Nick Bundy of N Bundy Electrical - a NAPIT-registered electrician from Staffordshire - walks through a real kitchen installation in "HOW TO Install an Induction Hob into an Existing Kitchen". He covers the circuit capacity checks that often catch people out, including what to do if the existing cable is undersized for a modern high-power hob.
1. Check the existing circuit is adequate
Open the consumer unit door and find the cooker circuit MCB. Note its rating - it will be 32 A, 40 A or 45 A in most UK homes. Then check the hob's rating plate (usually underneath) for the maximum rated current. The circuit MCB must be at least as high as that figure.
Cable size matters too. The most common sizes for cooker circuits are 6 mm² twin and earth (rated around 40–47 A clipped direct under BS 7671) and 10 mm² twin and earth (around 57–64 A). If the cable runs through insulation or is bunched with other cables, the effective rating drops - this is where an electrician's judgement is needed.
If you are converting from gas to induction, you need a brand new circuit run from the consumer unit. That is Part P notifiable work and you cannot legally self-certify it.
2. Isolate at the consumer unit and prove dead
Switch the cooker MCB off. If your consumer unit has locking clips, use one - it stops someone unknowingly switching the circuit back on while you are working. Tape over the MCB if you have no clip.
Go to the cooker connection unit on the wall. Unscrew the cover to expose the terminals. Touch your voltage tester to each terminal: Line, Neutral and Earth. All should read zero volts. If any reads live, go back to the consumer unit and check you turned off the correct circuit.
3. Disconnect the old appliance
Take a clear photo of the wiring before you touch anything. You will be glad you did if you need to refer back. Note which conductor - brown, blue or green-yellow - goes to which terminal (L, N, E).
Loosen the terminal screws one at a time and remove the old flex. If the flex passes through a strain-relief gland in the base of the CCU, undo that too. Put the old hob aside.
4. Check the cable, CCU rating and earthing
With the flex removed, inspect the cable tails inside the CCU. Look for discolouration, brittle insulation, or any sign that the terminals have been running hot. If you see scorch marks around any terminal, replace the CCU before fitting the new hob.
Check the CCU's current rating - it should be printed on the front cover or inside the terminal housing. A 45 A CCU suits most modern induction hobs. A 32 A unit may be fine for hobs rated under 7.2 kW but check the hob's specification to be certain.
The earth conductor (green and yellow) should be sleeved - not bare. If it is bare, slip a piece of green-yellow sleeving over it before you connect anything.
5. Connect the induction hob
Thread the hob's supply flex through the cable entry at the base of the CCU, making sure the strain-relief gland grips the outer sheath rather than the conductors. Typically you need around 100 mm of conductors inside the box to make comfortable terminations.
Connect brown to the L terminal, blue to N, and green-yellow to E. Tighten each terminal screw firmly - a loose connection here will cause overheating. Many CCUs use a tunnel-type terminal with a single clamping screw; tighten until there is no play when you tug gently on the conductor.
Close the CCU cover and tighten its two screws. Position the hob in the worktop cutout and connect any retaining clips the manufacturer supplies.
6. Restore power and test every zone
Back at the consumer unit, switch the cooker MCB back on. Turn the hob on and test each zone at a low heat setting. Leave all zones running briefly and check that the MCB and any RCD on that circuit hold - they should not trip under normal load.
Finally, press the RCD test button on the consumer unit (or the RCBO test button if the cooker circuit has its own) to confirm the protective device still operates. Reset it and you are done.
When to call us
Connecting a new induction hob to an existing, correctly rated circuit is a job many careful homeowners manage safely. The circuit upgrade side - new cable, new MCB, converting from gas - is a different matter. That needs a Part P-registered electrician with the test equipment to verify the circuit before it goes into service. Based in Sandwich and covering east Kent, Richard can assess your cooker circuit and carry out any upgrade needed.
Upgrading a kitchen in Sandwich?
Richard checks and upgrades cooker circuits for induction hob conversions across east Kent. Minor Works Certificate included with every job.
Contact Richard