I would put your electrician out to graze, he must be an outdated dinosaur or maybe a domestic installer !!
Look up the history of the ring main, it came about due to a copper shortage and not for being the better solution. Quote
" Ring final circuits originated in the UK, for historic reasons dating back to 1942 and the reconstruction effort following World War Two.
The Post-War Building Studies Committee No.11 was convened by the Council of the Institution of Electrical Engineers in June 1942. It was tasked with making recommendations to facilitate the building of the one million houses predicted to be required in the aftermath of the war.
In the face of shortages of materials, ring final circuits were conceived, to minimize the amount of copper required. The 13 A socket-outlet with fused plug top to protect appliance flexes was also introduced at this time. It was said that the ring final circuit typically required 30% less copper and could save up to 25% in cost. This allowed 15 A sockets to be installed in all rooms cost-effectively. "
A radial runs from the board through each socket and then stops, no return back to the board. A ring on 2.5mm cable and a 32 amp protective device is only safe when the ring is unbroken, if there is a break then the 2.5mm cable is insufficient for the current needed to cause the protective device to function.
