A power failure at a Brooklyn Con Edison substation caused ?massive ?delays to several subway lines ?including in Manhattan ?Sunday, prompting Gov. Cuomo to demand a probe into the energy provider. The outage, which occurred around 1 pm, sent Con Ed service crews scrambling to make repairs at the substation in downtown Brooklyn and to power lines in Red Hook. "There was a transmission disturbance that caused a voltage dip," said Con Ed spokesman Michael Clendenin. "That's what caused the signal problem with the subway." Clendenin noted that even though the dip was momentary and would have caused lights to dim, it would also require the MTA to reset its signaling system on some lines. In a statement sent out just before 5:30 pm, Cuomo slammed the outage as "completely unacceptable." "The apparent failure at Con Ed substation Sunday afternoon was completely unacceptable, affecting Brooklyn NYCHA residents and passengers on Subway trains across the city," Cuomo said. "Con Ed must be held accountable for the multitude of issues with their infrastructure that are too frequently impacting the lives of millions of New Yorkers." Cuomo - who has come under fire for the state of the subway system, which he ultimately oversees - also said he was directing the state Department of Public Service "to conduct an immediate investigation." A spokesman for Mayor de Blasio did not immediately respond. According to an email from the MTA, the disruption was caused by a manhole fire and normal service resumed around 5 pm.