FUSE BOX MCB FITTED

Get someone competant back to find why it was tripping, fix the problem and reinstate the RCBO as soon as poss. He has contravened the regulations here by putting in a MCB. What a bodger he is.

If the installation should be RCD / RCBO Protected and currently isn't, then it doesn't comply with the latest regulation. Because you have a new Consumer unit fitted, the installation should comply with current 17th Edition 3rd Ammendment regulation, and without RCD Protection it doesn't. This could cause issues with insurances and can also compromise safety. Hope this helps, If you need further answers of advice then I may be able to help further dependant on your location. David D.A.K Electrical

A mcb protects you for over current like a fuse blowing, a rcd protects you for a fault to earth ie if you touch a live terminal it should trip out. If there is a earth fault that keeps tripping the rcbo which is a combined mcb & rcd then that circuit should be isolated ( switched off ) as there is a risk potential. Putting a mcb in to make a circuit work that has a known fault is very alarming and potentially dangerous.