Democratic U.S. Rep. Ron Barber’s lead over Republican challenger Martha McSally grew with the latest batch of votes counted by Pima County election workers. But the Congressional District 2 race remains too close to call.

Out of more than 285,000 ballots already counted, Barber’s lead is a scant 1,402 votes. He is getting 50.15 percent of the vote to her 49.66 percent.

About 16,000 provisional ballots remain to be counted in Pima County, but there is no way to determine how many of those fall within CD2 rather than Congressional Districts 1 and 3.

CD2 also includes Cochise County, where all the votes have already been counted.

Pima County workers tabulated more than 11,000 provisional ballots Friday.

They plan to spend most of the weekend processing additional provisional ballots before putting the next group through ballot scanners on Sunday.

Provisional ballots are required if a voter receives an early ballot and then decides to vote at their polling place instead, which means workers have to check to make sure they didn’t vote twice. Provisional ballots are also cast by voters who may not have shown up on polling place rosters, those who reported to the wrong polling place and those who didn’t have the proper identification. All those potential problems have to be checked out before the votes can be counted.

In a second, even closer, race awaiting the final vote count, the city of Tucson’s Proposition 409, a $100 million package of road repair bonds, now has a 583-vote margin of approval.