In my house I have a board in very good condition with perfect keys and in good operation but my differential key does not enter because there is no more space Is it necessary to buy another bigger board, or do I embed a smaller box next to the board where only my differential fits? which would be cheaper thanks for your replies

If that were my board, I would choose to take out the 4 screws and remove the cover ..... then I would cut the cover plate so that a large square is left (That the square is determined between the numbers 1-3-5- 2) so that thermomagnetic and circuit breakers are visible to be able to operate them. Then, instead of the thermals being in that direction, I would put 2 DIN rails horizontally and buy new thermomagnetic to attach them to the DIN rails in conjunction with the differential circuit breaker ..... I calculate that they will enter you and they will be standardized (above powered and down de-energized). For that reason I would recommend you to inspect this type of thermals well since they seem old and it has happened to me that some have a only thermal replacement and not a magnetic one as the most modern ones have a spark arrester chamber and others. Regards!

Hi What is not understood is if the photo you uploaded is from your board or is a photo obtained on the web ... because on the one hand you ask between two options which is the most convenient and economical, and on the other hand you show a photo in where I already opted for an option so the question would not make sense, so I conclude that this photo does not show your board The cheapest option is going to be a box next to it. I would recommend a little bigger to give rise to some added future you remove the back cover from the big box you must break the wall a few centimeters between boxes to place 2 communication pipes. .Calculate the distance between boxes according to what they manage to cover their tapss so that it comes close to each other but does not overlap. Then, once interconnected, you swipe the box. You put the covers and these will cover the broken (as long as you have not broken too much) Cheers