Are there any sort of regulations for employees who do a manager's job but aren't classified as such? There are employees here who act as a night shift manager, are responsible for what happens and have to answer for it the next day, but they aren't classified as such.

There are no laws requiring an employer to "classify" an employee as a manager no matter what duties they are performing.

That's the short answer.

But the devil is in the details, so before we tell you if there are any OTHER laws being violated, why don't you tell us what difference it would make to the employee if they WERE classified as a manager.

Would it affect pay? Benefits? Hours?

It would affect pay, at the very least, as managers are paid more. Even barring that, they have to show up an hour before everyone else, and for awhile they were paid for that extra hour. Now they're supposed to find time during the week to cut hours (nearly impossible for some of them), and if they can't cut time, it's comp time.

Okay, now we're going to have to get into the down and dirty details.

At one time not too long ago I had a job where I worked the night shift. In all respects but two my job was exactly the same as anyone who worked the day or evening shifts; I had one responsibility that only the night shift performed, and since there was no manager on duty I occasionally had to make decisions that on the other two shifts a manager would normally make.

But since I only very occasionally had to assume the role of a manager and since all my other duties were the same as the other two shifts, I was not considered a manager. I was paid a shift differential, and the one responsibility I did that the other shifts didn't do earned me another differential. But I was not considered a manager and did not have either the pay or the benefits of a manager.

How much of the job is a manager's duty? How often does it occur? Is it happening regularly or just occasionally? Is it expected to go on indefinitely or is this more or less permanent? Are the management duties in addition to the employee's regular job or is all that they do management?

... it's comp time.

Also, legally "comp time" is something that only effects certain governmental employees. A private sector employee who is legally entitled to overtime cannot have comp time used to finese the paid overtime requirement. Comp time maybe can be legally used with private sector employees who have no legal right to paid overtime.

How much of the job is a manager's duty? How often does it occur? Is it happening regularly or just occasionally? Is it expected to go on indefinitely or is this more or less permanent? Are the management duties in addition to the employee's regular job or is all that they do management?

We do different jobs every night, and night shift manager (we have another word for it) is a job that someone different does each night, although it's only 4-5 of us out of the whole group who ever do this shift. It's the position of ultimate responsibility to make sure our product gets out the door -- they make decisions, assign duties, keep track of production flows, troubleshoot, lead the team overall, etc. If deadlines aren't met, they are ultimately responsible for that. It used to be a manager's job, but we were downsized and now it's non-managers in that role every night. There are no actual managers here at night. It's a permanent thing. And it's acknowledged that we are doing a manager's job without the title.

As for comp time, if asked, they would give us OT, but it's strongly encouraged that we make that not happen, by finding places to cut our hours in other parts of the week ideally.

NC follows the federal OT rules as is, and under the federal rules, overtime is hours worked past 40 in the same workweek. Someone working late is not legally overtime, not by itself anyhow. It is perfectly legal for the employer to tell the employee to work shorter days later in the workweek to avoid paying overtime.

However, failure to pay overtime actually worked (hours worked past 40 in the workweek) by a private employer violates the law, period.

http://www.dol.gov/esa/regs/compliance/whd/whdfs23.htm

"Overtime Pay May Not Be Waived: The overtime requirement may not be waived by agreement between the employer and employees. An agreement that only 8 hours a day or only 40 hours a week will be counted as working time also fails the test of FLSA compliance. An announcement by the employer that no overtime work will be permitted, or that overtime work will not be paid for unless authorized in advance, also will not impair the employee's right to compensation for compensable overtime hours that are worked."