The contracted power rating is one of those concepts that appears on the electricity bill but that almost nobody fully understands
If you've ever had a blackout at home just when you had the oven, the ceramic hob and the air conditioning turned on at the same time, you've probably experienced first-hand what it means to have too little contracted power. And if you've spent years paying for a very high power rating without anything ever tripping, you might be paying more than you need to.
The contracted power is something worth reviewing from time to time, because it has a direct impact on what you pay each month, regardless of how much you consume.
What exactly is the contracted power?
The contracted power is the maximum limit of simultaneous consumption that you can have in your home at any given time. It is measured in kilowatts (kW) and appears in your contract with the electricity supplier and on your bill.
When the instantaneous power consumption of all the appliances you have turned on at the same time exceeds that limit, the system detects it and cuts off the supply. This is what happens when the power goes out because you’ve turned on too many things at once and you have to go to the fuse box to flip the switch back up.
How to know if your power supply is insufficient?
The clearest sign is the power control switch tripping fairly frequently, especially at times of peak consumption: when you are cooking, when you have the air conditioning or electric heating on, or when several high-consumption appliances coincide.
If this happens to you more than once or twice a month, you probably need to review your contracted power supply. It is not a problem with the installation itself, but rather that the limit you have contracted does not suit your actual usage.
How to know if you are paying too much
The other side of the problem is contracting more power than you actually need. Many people have a high capacity contracted because at some point they were told it was recommended, or because they inherited it from the previous owner, and they have been paying a fixed monthly standing charge for a capacity they never use.
A simple way to check this is to see if your circuit breaker has tripped at all in the last year. If you can't remember the last time it happened, you may have room to lower your power rating and reduce the fixed part of your bill.
Which appliances consume the most and how they affect power capacity
The appliances that demand the most power instantaneously are the ceramic hob, the electric oven, the air conditioning, the electric heating, the washing machine, the dishwasher and the electric water heater. If you have several of these running at the same time, the consumption adds up and can easily exceed 4 or 5 kW.
For a standard home with these appliances, a contracted power supply of between 4.6 kW and 5.75 kW is usually sufficient if a little care is taken not to turn everything on at once. For larger homes or those with higher consumption, it may be necessary to contract a higher amount.
Who can help you decide?
Changing the contracted power is a procedure that is done with the electricity company, but before doing so it is worth having an electrician check whether the installation is prepared for the power you want to contract. Increasing the power without the consumer unit being correctly sized can cause problems.
At Iluminamos tu Vida we can check your installation and advise you on which power rating makes sense for your home and your actual consumption. If you've had doubts about this for a while, give us a call and we'll help you clear them up.