Most serious cause of repeated MRT train breakdowns

By now it should be quite obvious that the most serious problem behind the repeated MRT train breakdowns is electrical. The most serious cause of electrical failure is the use of sub-standard electrical cables. With so many scholars employed by the government to run the Ministry of Transport and SMRT, didn't anyone of the scholars ask for Mill Certificate from the manufacturers of the cables before passing of payment? Shouldn't the judge or prosecution hearing the recent breakdowns look into this vital issue?