Hundreds of ESB technicians who yesterday supported the opening day of a strike at the company are expected to return to work today.
In a statement issued last night, shop stewards in the TEEU said their colleagues were not prepared to continue supporting the strike called by the ATGWU.
That union issued a thinly-veiled threat, however, that the strike could be escalated to include power stations, a move that would lead to power cuts.
ATGWU power generation staff, who are not involved in the strike, said in a statement they would take a "positive approach" to any request from their colleagues for support.
Yesterday's opening day of the strike, the first at the ESB since 1991, caused only minimum disruption.
Despite fears of delay in repairing local breakdowns, the company said about 40 such repairs were carried out yesterday in the normal timeframe.
Only 100 new connections to the national grid were made, however, instead of the 300 that had been scheduled.
The company was also forced to cancel network renewal work due to be carried out by external contractors.
A spokesman said this could have "commercial implications" for the ESB, given that contractors would expect to be paid regardless of whether work was carried out.
The strike by ATGWU network technicians is over the extent to which outside contractors are involved in the delivery of a €3.6 billion programme to upgrade and modernise the company's network.
About 1,700 external contractors are at present employed by ESB Networks, alongside some 2,200 staff technicians. More than half of these are represented by the ATGWU and most of the remainder by the TEEU, while a small number are in Siptu.
ATGWU official Brendan Ogle said last night the strike had been solidly supported, but this was disputed by the ESB.
It claimed about half of its network technicians had returned to work by yesterday afternoon, including a "significant number" of ATGWU members.
In any event, the union is unlikely to have the support of TEEU members today.
In their statement last night, the TEEU shop stewards said any solidarity shown to colleagues on the strike pickets was "only a recognition of personal camaraderie that exists between fellow workers in the same base.
"It is not given to show any level of support for the dispute, the ATGWU who are organising it or for any official or committee of that union."
Responding late last night, Mr Ogle said it would be surprising if workers in any union passed official union pickets.
