How to fix RCD faults?
first of all unplug all the appliances from downstairs sockets and try to reset the RCD if RCD reset back then you don't need to go farther but if RCD does not reset than you need to investigate more if you are an electrician and you are reading this text then you can understand next paragraph if you are not qualified electrician then you should call an emergency electrician who can come and sort out this problem
RCD stands for residual current device always this have 2 poles one is for live wire and other ball is or neutral wire a single phase connection RCD is comparing current of live and neutral wires all the time if any of the wire's current is not equal to each other's it means live and neutral parts of RCD will sense it and that will cause the RCD to trip so single phase and three phase RCD work in same manner in single phase one wire is comparing to another but in three phase 3 live wires are comparing to one neutral wire so it means what all current which current is going into the system it should return back but not the voltages actual energy is stored in voltages but quantity of the current stays same so that's why the returning current should be equal to to the entering current so RCD helps to detect any leakage current into the system so
what is the benefit of an RCD? and why do we use RCD?
The main reason of using an RCD is to protect the user from electric shock in most of the cases if RCD is tripping due to the sockets then it means there is some problem inside the ring main or the Spur or the radial circuit of sockets it means that at some point into the ring main live or the Neutral wire is touching to the earth wire so because in actual earth is a second potential difference point to live that is why the current flows towards the earth that is why the entering current is not returned to the Neutral wire that's why the RCD sensed the difference and so that made the RCD to trip if that is not the case then RCD device are not installed correctly it means of your one of RCD wires are going into another RCD part