Hello to avoid making any kind of mistake it is best to start on the board with the two wires to change and move towards the end first the trunk line and then one by one all the descents What I mean is that you don't do it in sections or in a messy way It is important to follow a color code and not mix colors ... if I lack brown and I have blue left over I do not use blue instead of brown, I go and buy the missing brown it would take a third protection cable (ground) green with yellow but it does not work or fail The recommended colors are: brown phase light blue neutral green earth with yellow returns another color other than white example the installations are made by whole sections without cuts these tips will ensure success now if you have live in both poles it may be for 1- neutral cut .. the phase passes the loads and returns through the cable 2- induction .... the phase induces a voltage on a conductor, for this the induced conductor must not have any connection to anything evidently you did not follow an order when you made the changes and at some point you did not connect the neutral however it could have been opened inside or before the board due to the short circuits suffered connect and check the thermal to see if there is the neutral. If there is no neutral if there are other thermal or differential before reaching the first thermal where you will measure the entrance of the same If there continues the problem you should call the company regards