The Transmission Company of Nigeria (TCN) and the Kaduna Electric have cut electricity supply in Kaduna since Sunday morning.
The companies said the Nigeria Labour Congress (NLC) forced them to stop operations as it was protesting the mass sack of workers by the state government.
According to a statement by the General Manager, Public Affairs, Ndidi Mbah, TCN had resisted the intense pressure from the union on Saturday, demanding that all 33 kilovolts (kV) feeders radiating from the transmission substations within Kaduna State be switched off.
"Regrettably, the union functionaries returned today (Sunday) with similar demands amid palpable threats that could escalate and jeopardise national grid security.
"It was during this morning's encounter that the system operators were forced to shut down the 33kV feeders from 6:36 hours this morning.
TCN said, before then, Kaduna Electric had shut down its 11kV feeders since 3:00am on Sunday.
"TCN is mindful of the inconveniences this would cause electricity customers within the state and prays for a peaceful resolution between the parties to enable the restoration of bulk power supply to our substations for Kaduna DisCo to take to its electricity customers."
On the part of Kaduna Electric, a statement by the Head, Corporate Communication, Abdulazeez Abdullahi, on Sunday said, "The management of Kaduna Electric regrets to inform its customers in Kaduna State that the service interruption currently being experienced in the state is as a result of the industrial action embarked upon by the NLC.
"In compliance with the NLC directive, the TCN has knocked off all our 33KV lines in Kaduna State."
The company feared that the shutdown could result in vandalism of power installations and called for vigilance from security operatives.