This question was asked by Artyom. Read the text of the question a little below.
This is the 14th part of a series of publications - "Electrician Q&A". Who missed the past parts - as always, I remind you that in this and past publications (parts) I bring real questions from readers and my answers to them. I continue to do so in this part.
I quote the text of the question verbatim:
Hello. The question is, there is a shield in the house in it, a common machine for 25 A, behind it there are 4 pieces. 16 A. So, everything works fine, until we turn on the boiler, then it turns off the common one at 25A. Can I replace it with 32 or 40? I also heard somewhere that 16A is put on lighting, but 25 is needed for sockets, is that so?
Wiring on machines 3 mm. The question is more about security, since the house is made of timber and everything is hidden in the walls. In addition, I would like to understand that for an electric stove, you do not need to bring anything extra from the street, is it enough to bring the "ground"?
I gave Artyom the following answer due to my knowledge and qualifications:
Of course, you can replace the circuit breaker with a more "powerful" one, but alas, this may not solve the problem. First, determine the reason why the circuit breaker knocks out. If the protection trips after a certain period of time after switching on, then this is a consequence of the line overload in excess of the circuit breaker rating. If the circuit breaker de-energizes the electrical circuits immediately after turning on the boiler, most likely the cause is a short circuit.
Circuit breaker overload can indeed be eliminated by installing circuit breaker with a higher rating, but at the same time you need to correlate the new device with section of the wiring. You write that you have a cross section of 3 mm2, but the standard series does not contain such a value, so I will give the closest: for 2.5 mm2 copper, the permissible continuous load is 27 A, and for aluminum lived 22 A. For a cross-section of 4 mm2 for copper, the permissible continuous load is 38 A, and for aluminum conductors 28 A.
If the reason is a short circuit, then the input circuit breaker with a rating of 25 A can trip faster than automatic switches for 16 A due to the parameters of the time-current characteristic, which is indicated by a letter in front of the rating, as shown in the figure below:
Replacing the circuit breaker will not eliminate its tripping. In the event of a short circuit, you need to check the electric boiler and repair the damage.
For sockets and lighting, the rating of the circuit breaker is also selected depending on the size of the load connected to them. What you've heard is 16A for lighting and 25A for wall outlets are general guidelines. In practice, 16 A can also be sufficient for wall outlets if low-power devices are connected to them, and a 10 A circuit breaker is sufficient for LED luminaires.
The electric stove is also connected from a common electrical circuit on a par with other electrical appliances. It is advisable to connect the protective PE conductor to all devices for safety reasons.