Find the isolator before doing anything else
Look along the wall near the oven and above the worktop for a switch, often marked for the cooker or oven, sometimes with an indicator light. Check it is on. Then check the breaker at the consumer unit, fully off and fully on. Between them, those two switches account for a large share of built-in ovens declared dead.
What you find
- The display is completely dark with no response at all — Total absence of power rather than a control problem.
- A switch near the oven that is off or that nobody uses — The top cause, and it is invisible until you go looking for it.
- Other kitchen appliances work normally — It narrows the problem to this circuit rather than the supply generally.
- The oven worked until somebody cleaned or worked in the kitchen — The circumstance in which an isolator gets switched off.
- The display lights but no function will start — A different branch, pointing at modes, locks or the control.
- NEAR MISS: a clock flashing after a power cut — Power is present, so this is not the no-power case at all.
Ranked for a dark built-in oven
- An isolating switch turned off — First. It is on the wall rather than the appliance, it is unlabelled on many installations, and it is switched by accident regularly.
- A tripped or partly tripped breaker — Second. A breaker that looks on can still be tripped, so it needs cycling fully rather than inspecting.
- A supply fault in the connection behind the appliance — Third, and it belongs to an electrician rather than an owner.
- An internal fault — Last, and it is what remains once both switches are confirmed.
Two switches, then hand over
- Find and check the isolating switch near the oven — The top cause, free, and often behind something on the worktop.
- Switch the breaker fully off and fully on — It clears a partial trip, which looks identical to a healthy breaker.
- Check whether other appliances on the same circuit work — It separates this appliance from the circuit as a whole.
- Call rather than investigating the connection — A built-in oven is hardwired and its connection is not owner work.
Owner steps
- Look along the wall and above the worktop for an isolating switch — It is often unlabelled and frequently hidden behind something on the counter.
Tools: flashlightAbout 10 min
- Switch it off and on once and check for an indicator light — Many have a neon indicator that shows whether the circuit is live.
About 5 min
- Switch the oven breaker fully off, wait, and switch it fully on — A partly tripped breaker supplies nothing while still looking on from a distance.
About 10 min
- Check whether other appliances on the same circuit still work — If they do not either, the problem is the circuit rather than the oven.
About 10 min
- STOP before the oven is withdrawn or any connection is opened — It is hardwired, heavy and awkward, and that connection is electrician's work.
Before anything is opened
Safety
Switch off the breaker rather than looking for a plug: most built-in ovens are hardwired and cannot be unplugged. Never reset a breaker repeatedly if it trips again. Do not attempt to withdraw a hardwired oven from its housing. Let the cavity cool completely before going near it, and stop at once if you smell burning.
When to call
Call an electrician if the breaker trips when switched on, if the isolator has no indication of life, or if other appliances on the circuit are affected. Call an appliance technician if both switches are confirmed live and the oven is still dark. Say which switches you have already checked: it saves the visit starting from the beginning.
Nearest pages of this class
Scope
Written for the Bosch oven class rather than one model line. Isolator positions belong to the kitchen rather than the appliance, and the installation instructions for your model describe its own supply arrangement.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
