JOHANNESBURG, Nov 9 (Reuters) - The chief executive of South African power company Eskom resisted calls to resign from trade unions and a business group on Tuesday amid severe electricity cuts across the country. Miners" union NUM and metalworkers" union NUMSA, as well as the Black Business Council, this week called for Andre de Ruyter to either step down or be fired as Eskom ramped up outages in response to multiple faults at its coal-fired generation fleet. De Ruyter took charge of state-owned Eskom in January 2020 and has won plaudits for a long-term plan to transition away from coal and towards cleaner energy sources, but under his watch a maintenance programme has failed to lift power availability as hoped. Africa"s most industrialised nation has experienced recurring power cuts for more than a decade that have constrained economic growth. "I understand that there are frustrations that we are not achieving our objectives as quickly as we would like to, but these frustrations will not be resolved ... by changing horses at this point in time," de Ruyter told a news conference, saying continuity of management was important. Eskom"s current leadership partly blames repeated breakdowns at its coal units on a decision by previous management to defer crucial mid-life repairs. De Ruyter said Eskom planned to reduce the current "Stage 4" scheduled power cuts to Stage 3 on Wednesday and again to Stage 2 on Friday before suspending the outages on Saturday, as some generation units are due to come back online. Stage 4 outages require 4,000 megawatts (MW) to be shed from the national grid, versus Eskom"s total nominal capacity of around 46,000 MW. On Monday more than 20,000 MW of Eskom"s capacity was offline either because of breakdowns or maintenance work.