Cooker keeps tripping the electrics
A cooker that trips the breaker is reporting a real electrical fault, and which function trips it usually identifies the part in one test.
What it usually means
A breaker or residual current device that trips when you use the cooker is not being oversensitive. It is doing the job it was fitted for, and the useful thing about it is that it fails informatively: what you were doing at the moment it went is most of the diagnosis.
A cooker is a set of large resistive elements — an oven element, a grill element, sometimes a second cavity, plus the hob — fed from one heavy circuit, typically thirty or thirty-two amps. Elements fail in a characteristic way. The resistance wire inside sits in packed mineral insulation, and that insulation absorbs moisture as it ages or after a spillage or a wet clean. A damp element conducts a small current to earth, and once that leakage exceeds the residual current device's threshold, the device opens. The reason it so often trips as soon as something is switched on, or a few minutes into heating, is that the leakage rises as the element warms.
That gives you the test. Try each function on its own, from cold: oven, grill, each hob zone, the second cavity if there is one. Whichever one trips it is where the fault is, and an element is a routine, inexpensive part. If it trips the moment the circuit is switched back on with everything off, the fault is not in an element being used — it is in the wiring, the terminal block, or something that is live all the time such as the lamp or a control module.
A residual current device also protects other things. On many consumer units it covers several circuits, so a cooker that appears to trip the board can be innocent — the classic is a shared device where the real fault is a kettle, an outdoor socket or a light fitting. If the trip takes half the house out rather than only the cooker, that is worth knowing before anyone is called.
What matters most is what not to do. Resetting a device that keeps tripping, repeatedly, is the one response to avoid: each reset re-energises a fault that has already been detected, and the device is the only thing currently standing between that fault and somebody touching the appliance. If it will not stay in, leave it out.
How to narrow it down
Work through these in order.
What were you doing when it tripped?
Write it down as precisely as you can: which function, how long after switching on, and whether the oven was already hot. Leakage from a damp element rises as it heats, so a trip within seconds and a trip twenty minutes in point at different things, and an engineer arriving with that information starts much further along.
Does one function trip it and the others not?
Test each in turn from cold, giving each a few minutes on its own with everything else off. If the grill trips it and the oven does not, you have found the faulty element without opening anything. If every function trips it, the fault is more likely in the supply, the terminal block or a shared component.
Does it trip the instant you switch the circuit on, with all the controls off?
Then nothing you are operating is causing it, and the fault is in something permanently connected — the internal wiring, the terminal block where the cable lands, a control module, or the oven lamp. That is not a use-it-carefully situation: leave the circuit off until it has been looked at.
Does it take out the whole house or only the cooker?
A device protecting several circuits will trip on a fault in any of them, so if the lights and sockets go too, the cooker may be innocent. Unplug everything else, reset, and add appliances back one at a time. This is worth doing before booking a cooker engineer for a kettle.
Has the cooker been cleaned recently, or has anything boiled over?
Water is the usual reason an element starts leaking to earth: a wet clean, a spillage that ran down inside, or steam from a pan boiling dry underneath a grill element. Sometimes running the oven warm with the door ajar for an hour dries it out and the trips stop, and sometimes the insulation is permanently spoiled.
Is it a breaker or an RCD that is going?
They mean different things. A breaker with only a number on it trips on overcurrent, which suggests a short or too much load. A device with a test button is a residual current device, and it trips on current leaking to earth, which is the classic failing-element signature. Which one moved is worth reporting.
Is anything scorched, discoloured or smelling hot?
Look at the cooker switch on the wall and the plate where the cable enters the appliance. Browning, a smell of hot plastic or a switch that is warm to the touch is a connection problem rather than an element one, and it is the version of this fault to treat as urgent rather than inconvenient.
Codes commonly shown with this
- U400All brandsA 400-family code means the cooker has been connected to the wrong supply or wired incorrectly. Five badges from four manufacturers publish a version of it, and it appears at installation.Get it checked
- How to isolate a range cookerAll brandsAn electric or dual fuel range cooker has no plug: five manufacturers describe a wall switch near but not above the cooker on a 30 or 32 amp circuit. All-gas ranges are the exception.Usually simple to fix
- E3 or E4BellingBelling send you outside the manufacturer for this one: the supply voltage may be too high or too low. Switch the cooker off at the wall and contact your electricity board.Get it checked
- E5SmegThe hob has judged the mains voltage signal invalid. Smeg say to check the supply voltage, which on a hardwired cooker is an electrician’s job rather than yours.Get it checked
- E6SmegPower failure to the power board. Smeg publish a timed remedy rather than a flick of the switch: turn the appliance off for a full five minutes.Get it checked
When it is urgent
Take care
What it costs
Typical repair cost
£80–£300
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Get an engineer to look at this
We do not pass enquiries to a repair firm, so there is no form here. When you book a qualified appliance engineer, tell them the make, the model and the exact code or message on the display, and ask whether they carry parts for this make — that is what turns one visit into a repair rather than a quote.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.