How to calculate how many whitegoods can be switched on at the same time in Spain

You are watching TV, you turn on the washing machine and oven and experience a general blackout. This is because you have exceeded the power that your installation admits or that some appliance has a fault in the connection to the electrical outlet.


At a time when the electricity bill is a big news in Spain, it does not hurt to know how many devices we can have connected at home without the fuses jumping off and for that, it is essential to control how much the appliances we have at home consume and know the systems that they can prevent us from unwanted accidents.


Know the power at home.

If we have to start from a point it is to know the contracted power with the electric company and it is in the consumption where the key is. We are used to buying household appliances and appliances and many times we do not take into account the contracted power in our home.

With this term we refer to the numerical value that relates the number of appliances that we can connect at the same time in our house without tripping the Power Control Switch (ICP). A value that is expressed in kilowatts (kW) and is known as a fixed term, an amount that also goes by sections and that we establish when we contract the electricity service.


Therefore, before formalizing the contract with the company that provides us with the electricity, it is interesting to calculate how much power we are going to need. There are different free pages that allow us to simulate our electricity consumption depending on the size of the house, appliances that we are going to use, people who live at home etc.

These simulators allow estimating the power that we are going to require at home to use a series of electrical appliances. In power calculators like this one from Iberdrola which you can find in English in the following link:, they refer us and ask about the size of the home and the electrical appliances that we have connected to get an estimate. But we can also calculate the power manually.

For this we must bear in mind that there are devices that consume a lot, such as ovens, dryers, electric heaters, air conditioners ... and all of them coexist with others that spend much less. Therefore, we must calculate which of these, especially the most "heavy", will work at the same time. The values given here are only indicative and can vary depending on the whitegoods.

Heating and stoves 800 to 2,500 watts

Dishwasher 1,000 to 2,300 watts

Oven 1,000 to 2,300 watts

Washing machine 1,000 to 2,000 watts

Air conditioning Up to 3,000 watts or more. Consult compressor installed.

Microwave Up to 1,500 watts

Television 400 watts

350 watt refrigerator

These are the typical elements that are in in general in most houses, but together with these we must add the rest of the connected devices. Computers, audio equipment, light bulbs etc. all these already offer a much lower consumption and are therefore more difficult to determine. Most of the small devices barely consume electrical power and for example a compact stereo will not exceed 20 watts. Labels and instructions give us that information.


The factor and the coefficient of simultaneity allow us to establish a calculation of the power that we are going to hire, which is very close to the power we have at home

In this sense, it is important to know and calculate the electrical power based on the devices we have at home and add their consumption. It is the so-called simultaneity factor, an estimated calculation based on the electrical appliances in the house, the use that we are going to require and the maximum contracted power that appears on our bill.

To the final figure, we must add a margin for the rest of the less powerful devices that we have seen before (for lighting, simply multiply the result of all the bulbs together by 0.66 and we will have an estimated figure) and take into account how many of all these devices will work at the same time. This is what is called the coefficient of simultaneity.

It means that when making the calculation it is not just about adding. From the equation we have to deduce the use and our routines. An example is that for example we are not going to use heating and air conditioning at the same time, so the element that requires less power is eliminated from the final figure.

The objective is to determine the highest kW figure that we are going to require from the installation, taking into account the electrical equipment with the highest consumption that we usually use simultaneously and that in this way if we turn on the air and the washing machine and connect them to the refrigerator, don't end up with the fuses going off. But this is only the beginning.

As an observation, in some devices the consumption may appear in watts ("W") and to obtain the kW you only have to divide by 1,000.


Power off, precautionary measure.

When we say that the fuses have switched itself off it is usually due to the fact that we have too many connected devices or bad connections, in these cases it may be due to factors in which  have nothing to do with the power connected.

With the expression "fuses off" we can have a problem in the general fuse box, 

If we talk about the main differential fuse, we refer to the first switch that appears in the electrical fuse box. With a power ranging from 25 to 40 Amps, it is the main protector of the electrical installation, it protects the whole circuit by switching everything off, against possible overloads and short circuits. It can also intervene, among other elements, the Power Control Switch or ICP, which is what determines if we exceed the power contracted in our electricity contract, although this is usually located by the general meter.

And it is this overloads that is the main problem. If we have many devices or devices connected or just a few, but with high consumption, we can exceed the consumption that we have contracted or my cause an over heating of the wiring, something that is maximized in an old or poorly wired installation. At that point the differential sets itself off and thus avoiding major problems that could even lead to a home fire.


The key is the Amps.

But having said all this and taking into account the general power contracted, we may have other limits at home in the form of power as well. If you look at the electrical panel, another series of regulators (circuit breakers) appear next to the general differential, which are generally grouped by zones or by types of devices. In each case we can have a number of say eight power limiters that correspond to different circuits.

These lever-shaped limiters are responsible for interrupting the electrical current in a circuit when a certain consumption of each electrical panel has been exceeded. Each of these mechanisms support a certain amount of maximum current that appears and can be printed on each lever with a value accompanied by the letter "A" for Ampere or some time the letter "C" is used.


For example, we may have powers ranging from 10A to 25A. This means that each of these limiters is able to withstand a certain amount of current. And although, for example, my general differential admits 40A, in a room I will not be able to connect and plug electrical appliances for more than 25A, since otherwise it will jump.

At this point a doubt may arise, since power or consumption is measured in watts and here we talk about Amps. To know the equivalence and the power that each limiter supports, we only have to multiply the 230 volts by the amperage of each limiter. For example, the one with 10A will not let me plug in more than 2,300 watts of power. A small amount and that is why it is intended for lighting only, while those that manage more powerful appliances admit an amperage and therefore a higher power.



10A         2.300W

15A         3.450W

20A        4.600W

25A        5.750W

30A       6.900W

35A       8.050W

40A       9.200W

This means that even if we have contracted 6,000 watts of power, for example, if the kitchen circuit breaker only admits 15A or what is the same, 3,450 watts, we will not be able to put a refrigerator, oven, vitro and washing machine together, since we will exceed the potential admitted by that limiter.

Therefore and in conclusion, to know what the installation at home can support without going into assess the state of installation (if the wiring is deficient for example), it is interesting to be aware of several aspects: the power contracted, the consumption of watts that we have at home and the amperage and watts supported by our electrical panel.


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