President Obama signs the Democrats’ health care bill into law in the East Room of the White House on Tuesday, March 23, 2010. (AP Photo/J. Scott Applewhite)

CNSNews.com) – A little-known section in the Obamacare health reform law defines “full-time” work as averaging only 30 hours per week, a definition that will affect some employers who utilize part-time workers to trim the cost of complying with the Obamacare rule that says businesses with 50 or more workers must provide health insurance or pay a fine.

“The term ‘full-time employee’ means, with respect to any month, an employee who is employed on average at least 30 hours of service per week,” section 1513 of the law reads. (Scroll down to section 4, paragraph A.)

That section, known as the employer mandate, requires any business with 50 or more full-time employees to provide at least the minimum level of government-defined health coverage to those employees.

In other words, a business must provide insurance if it has 50 or more employees working an average of just 30 hours per week, which is 10 hours per week fewer than the traditional 40-hour work week.

If an employer has 50 or more "full-time employees" and does not offer health insurance, it must pay a penalty per employee for each month it does not offer coverage.

The obscure provision recently reemerged in regulations issued by the IRS for how employers must account for which workers are full-time and which ones are not.

(AP Photo/Mark Duncan, File)

Under these standards, published in September, employers can choose a “look-back” period of between 3 and 12 months to measure if an employee has worked an average of 30 hours per week.

If an employee has worked 30 hours per week during this time, the person would count as a full-time employee for at least the next six months, regardless of how much they work, thus preventing employers from cutting hours to avoid the mandate.

In other words, an employer calculates the hours an employee works during at least a three-month period, determining if they employee has worked 30 hours or more per week on average.

If the employee meets the 30-hour threshold, they are counted as full-time for at least six months. If the employer has at least 50 such employees, he must provide them with health insurance or pay a fine.

The IRS regulations do not apply to seasonal or temporary workers, only to regular employees.