Practical, real-world answers from people who do this work every day.
We recently had an issue where the power was continually cutting out to the property we checked all of the appliances to see if anything was causing a power surge and we also checked for any water leakage or any potential issues with any sockets but everything was fine it was when we were boiling a cattle or we were using the boiler that there was an issue it turns out that we had missed a payment from a previous month due to a direct debit not running and the Portuguese power company had placed a 5 amp limit on our power supply simply clearing and paying the previous invoice restored our power within the hour