This article from North Carolina explains a few of the check and balances in the process to help protect the integrity of the process.  A local ABC affiliate in NC reported on their tour of the local election office:

Amidst a growing chorus of allegations from Republicans on voting fraud, ABC11 took an all-access tour of the Wake County Elections Board’s offices and inspected the checks and balances in place to protect the integrity and fairness of the election. “This is our career, this is our life,” director Gary Sims told ABC11. “These are our votes, too, so we care just as much about the election as anyone.