Hello I disagree with colleagues that the first thing is to complain. Before that it is necessary to see if such a claim is justified. It must be taken into account that a claim has a significant delay so that if it is not appropriate they tell us that it is not their problem and often they themselves wash their hands saying that the problem is not theirs when it is .... as a result a lot of time is wasted on something that at least there must be some certainty of knowing where we stand in front of the problem Then the first thing to do is to verify if the problem is external or internal, for this you have to connect as many loads as possible until the voltage drop is noticeable. Then measure voltage near said load and then step, measure voltage on the main board input first device, if the voltage there is very low then the problem is external but if the voltage is much higher than the other then the problem is internal, to All that is required is a tester, access to the inside of the board and 2 minutes to measure. From there it is known whether to make the claim and stand in spite of what the gang members say (If they deny it) or call a professional for the prompt solution or post here and see if you can solve yourself. . As an additional we must not stop thinking that the load is important, we talk about a house that because of having 3 air equipment is not of a low electrification degree precisely and we do not know details of how the installation is proposed Until this is resolved, do not place any type of elevator, stabilizer or whatever, such a thing will be high risk if the installation is not in condition comment