Utah Power & Light Co. and labor leaders entered a third negotiating session Friday to renew another contract, and if management and labor can't agree a third party will step in to resolve the impasse.

But such an arrangement will not exist in 1990 and beyond, if UP&L has its way. UP&L notified the union about its plans to unilaterally terminate the 50-year-old arbitration clause in future contracts before current negotiations began.And the union is upset, saying that doing away with a third-party arbitrator opens the door for a strike or a company lockout, which threatens continued service to customers. Furthermore, labor leaders say they believe the move was inspired by Pacific Power & Light - UP&L's new sister utility since merging with Pacific Power's parent company in Oregon, PacifiCorp.

"It has nothing to do with the merger," UP&L spokesman Dave Mead countered.

More than 3,000 UP&L employees are members of the International Brotherhood of Workers local union 57. Since 1939, the union and UP&L have agreed that when both sides reach an impasse in contract negotiations, a third party would be brought in to resolve it.

While the union says the agreement has resulted in fair and reasonable settlements, UP&L says it has made it difficult to include wages and benefits in the company's program of cutting costs and power rates.

"In the recent past, when economic issues have gone to binding arbitration the balance between our wages and cost controls has been skewed toward" the union, Mead said.

IBEW business manager Blaine Newman said he feared the merger with Portland-based PacifiCorp would cause problems in future negotiations. "I hoped they wouldn't want to change that (arbitration clause). It was really startling."

He called the move "an implied threat of future economic action (and) a form of violence to which neither the employees nor the public should be subjected."

No disagreement over wages and benefits has surfaced so far in negotiations. But, UP&L said the intent of terminating the agreement is to give the company the ability to "balance wages with our costs and efforts to keep our rates competitive."

Wages and benefits account for 15 percent of a customer's electric bill.

But, Newman said backing out of the agreement endangers UP&L's customers by permitting a strike or lockout.

Asked if a strike could happen, Newman said, "It's possible, but I don't know." He explained the arbitration clause ensured against strikes or lockouts while differences were being resolved.

Mead said that can continue without bringing in a third party. He said other utilities, including PP&L, continue operations while management and labor directly work out their differences without a third party. "We should be able to do that."

IBEW is considering taking legal action against UP&L for unilaterally terminating the agreement. But, Newman said negotiations for the 1989 contract, which officially expired Thursday, will continue despite the dispute over the arbitration clause.