One of the unions representing ESB network technicians has said it can not support the strike by its fellow union, the ATGWU, and it urged its members to return to work as normal tomorrow morning.
The call came in a statement issued by a shop steward committee of the TEEU, which is not on strike.
The statement says that any solidarity shown to their picketing colleagues in the ATGWU today is only a recognition of what they call personal camaraderie that exists between fellow workers in the same base.
The ESB has meanwhile appealed to the ATGWU to call off its strike to allow talks to proceed.
However, the union's Regional Secretary, Brendan Ogle, said that he had no mandate to call off the strike before a schedule of talks is agreed.
Earlier today, ESB technicians were picketing company depots on the first day of their strike over the use of external contractors.
The ATGWU says it had no option but to take official strike action after ESB management cancelled a meeting scheduled yesterday aimed at averting the action.
The company says the numbers on the picket lines are small.
However, the ATGWU has rejected suggestions that its own members are not supporting the strike.
One ATGWU branch in Dublin South Central, representing about 100 technicians, said it was opposed to the strike and urged the union leadership to call it off.
Line supervisors in the union also called on the leadership to abandon the strike and return to talks.
Power supplies have not been affected by the action.
