It is recommended to cut the masonry walls for conduits using suitable mechanical means like a grinding machine & mechanical chipping and cutting machines. If an existing plastered surface is being cut over, it is recommended to mark the cutting surface. Use a grinder to cut the opening and then removing the Centre part.
Although it is not recommended to cut any structural concrete masses, if there is a requirement to cut the concrete mass for conduiting, it is essential to check & make sure that no reinforcement steel is cut to make room for the conduits. In case there is a need to cut the steel of the concrete member, please consult a structural engineer.