Why your power keeps tripping (ICP and differential switch)

Terms used

• ICP — The ICP is the power-limiting switch that cuts supply when you use more than your contracted power.
• Diferencial — The diferencial is the safety switch that cuts power when current leaks to earth.
• Magnetotérmicos — Magnetotérmicos are the circuit breakers in your fuse board, one for each circuit in the home.
• Instalador autorizado — An instalador autorizado is a licensed electrician allowed to work on and certify home electrical installations.

Key rules

• ICP trip: An ICP trip means you are using more than your contracted power, unless it trips with little load, which points to a fault.
• Diferencial trip: A diferencial trip points to a leak or faulty appliance, so raising your power will not fix it.
• Safety: Never bypass the diferencial or replace it with a higher-rated one.
• Raising power: More contracted power means a higher fixed bill every month, even when you do not use it.

Which switch tripped decides everything

Two different switches can cut your power, and they mean different things.

• The ICP (power limiter) trips when you use more electricity than your contracted power. It is an overload, not a fault.
• The diferencial trips when current leaks to earth. It usually means a faulty appliance or wiring, and it is a safety device.

Look at your meter box or fuse board. The ICP is normally in the meter box or the fuse board. The diferencial is in the fuse board and has a TEST button. The checklist below walks you through the reset steps.

If the ICP tripped

It trips when demand stays above your contracted power for long enough. A typical case is the oven, heater and washing machine running together. Switch off some appliances, then move the lever back up.

Smart meters can also limit power, so a smart meter can be the reason for a cut-out.

If it trips even with very little running, do not assume it is overload. The fault may be in the installation, so call an electrician.

If the diferencial tripped

It reacts to a small leak of current, typically 30 mA. Common causes:

• a damaged appliance such as a washing machine, dishwasher, water heater, oven or fridge
• moisture or water in sockets, outdoor lights or garden circuits
• damaged cable insulation
• an ageing diferencial that trips on its own

Unplug everything and reset it. Then switch the circuit breakers (magnetotérmicos) off, turn the diferencial on and switch the circuits on one by one. The circuit that makes it trip again is the faulty one. Unplug its appliances one at a time to find the culprit.

Call a licensed electrician (instalador autorizado) if it trips with nothing plugged in, trips again straight after a reset, or you smell burning, see scorch marks or feel tingling from appliances. Also call one if the faulty circuit is fixed wiring or the water heater. Never bypass the diferencial or swap it for a higher-rated one.

Should you raise your contracted power?

Raise it if the ICP trips often during normal use and changing habits is impractical. This is likely if you have electric heating, air conditioning, an induction hob, an electric vehicle charger or a heat pump.

Change your habits instead if trips are occasional or your home has few big loads. Run heavy appliances at different times and use night hours. This costs nothing.

Before paying for more power, rule out a fault. A trip can come from a fault rather than overload.

What raising power costs

• Extra power is a fixed charge per kW per year. You pay it every month whether or not you use the power.
• The tariff has two power terms, peak and off-peak.
• The charge is usually modest compared with energy cost, so a small increase is often cheaper than constant outages.
• Larger increases can bring a fee from the distributor. A change beyond the installation's maximum needs a certificate from an electrician. You may also need a new ICP.
• You can lower the power again later.

Ask your supplier for the current per-kW price and any fees before you confirm. The decision below sums up the options.

Choosing between options

Should you raise your contracted power or change how you use appliances?

• Change your habits: Trips are occasional or your home has few big loads. Staggering heavy appliances and using night hours costs nothing.

• Call an electrician first: The trip may be a fault, not overload: it trips with little load, or the differential switch is the one tripping. More power will not fix a leak to earth.

Rule out a fault first. If the ICP trips often during normal use and habits cannot change, raise the power. The extra fixed charge per kW is usually modest, so a small increase often beats constant trips. Higher power means a higher fixed bill every month, may need a new ICP, and the distributor may charge a fee.

Checklist

• Check which switch tripped: the power limiter (ICP) in the meter box or fuse board, or the differential switch (diferencial) on your fuse board.

• Note what was running when it tripped, such as the oven, heater and washing machine together.

• If the differential tripped, unplug everything and reset the diferencial.

• When it trips again, treat the last circuit you switched on as the faulty one, then unplug its appliances one at a time to find the culprit.

• Press the TEST button on the diferencial once a month to check that it works.

• Call an electrician if the ICP trips with little load, because the fault may be in the installation.

• Rule out a fault first, then ask your supplier about raising contracted power if the ICP trips often in normal use.

Frequently asked questions

Can I test my differential switch to see if it works?

Yes, press the TEST button on the diferencial once a month, and it should switch off straight away.

Do I need an electrician to raise my contracted power?

Sometimes, because a rise above your installation's maximum needs a certificate (boletín) from an electrician. Larger increases may also bring a fee from the distributor, and you may need a new ICP or a different switch.

Can a smart meter make the power cut out?

Yes, smart meters can also limit power, so a cut-out is not always your own switch.