Why does my ceramic hob switch itself off?

A glass hob with touch controls has more ways to switch itself off than a knob-controlled one, and almost all of them are protections rather than failures. The trick is identifying which one, because each has a different signature: instant and repeatable, after a fixed period, or only when things get hot.

Step by step

1. Dry the control panel and clear it completely.Touch controls respond to anything conductive. A damp cloth left over them, a boil-over running across them, or a pan handle resting on them all read as a permanent press, and the hob shuts down as a safety response. This is far and away the most common cause.
2. Check for the child lock and the key symbol.A lock engaged by a spill or an accidental long press disables the controls and can leave the hob appearing to shut itself off. The manual gives the unlock press for your model, usually holding one key for several seconds.
3. Look for an auto-off timer you did not set deliberately.Many hobs have a per-zone timer and a stop-time function. A timer set at some point and forgotten will switch that zone off at a consistent interval, which is a very repeatable and very confusing symptom.
4. Know that there is a maximum run time on every zone.Hobs are designed to switch off after a maximum period at a given power — typically an hour or two at full power and up to eight or ten at the lowest. If your hob switches off after a long slow simmer, that is the safety limit, not a fault.
5. Check the ventilation if it cuts out only when hot.The electronics under the glass are cooled by air drawn through gaps at the front or the back of the cutout. A drawer packed tight underneath, an oven fitted directly below with no gap, or insulation stuffed around the hob will make it overheat and shut down repeatedly after twenty to thirty minutes of heavy use.
6. Check whether it is the hob switching off or the supply.If the display goes completely dead rather than showing a residual heat symbol, look at the consumer unit. A tripping circuit is a different fault entirely and is covered by the tripping guide.
7. Note the pattern before you call.Instantly and always: control panel or lock. After a fixed time: timer or run-time limit. Only when hot and heavily used: cooling. Randomly with no pattern and no display: supply or control board.

Tips

• Never leave a damp cloth on a glass hob. It is the single most common cause of this complaint and it also risks scalding when the residual heat drives steam through it.
• Residual heat indicators — an H or a dot — stay lit after the hob is off. If they are showing, the hob has power and the problem is not the supply.
• If the hob was fitted at the same time as a new oven beneath it, check the manufacturer's required clearance between the two. Insufficient gap is a common cause of overheat cut-outs in newly fitted kitchens.

If it doesn't work