Generally under The Employee Retirement Income Security Act of 1974 (ERISA) and the tax code an employer may be penalized for excluding a purported “part time” employee from benefits where the employee has worked 1,000 or more hours over the course of a year. ERISA also provides guidelines under which an employer may enforce a certain "minimum service requirement" before an employee is entitled to benefits. These rules are designed to make sure that employers do not take advantage of or unfairly deny an employee of benefits, while still providing employers with the flexibility of hiring *genuine* part time employees. If an employer improperly excludes an employee from benefits the employer is subject to civil penalty and private lawsuits.
You’ll complete 1,000 hours of work in 25 weeks if you work 40 hours per week, however, your barometer for determining if you are entitled to benefits should not be the number of weeks worked at 40 hours, but rather how many hours you are going to work annually. For example, it is entirely possible to have to 1,000 hours worked without working any 40 hour weeks.
The employee handbook and the employer’s benefits policy must comply with ERISA and the tax code. So long as the benefits policy satisfies ERISA, the employer is bound by it, meaning that if you are entitled to benefits under the handbook then you get them. Still, the employee handbook has no ability to change the 1,000 hours worked rule.
Importantly, state law also plays a role in determining certain types of benefits eligibility and exclusion. There may be a relevant law in your state that I am not aware of.
My advice: (1) calculate how many hours you’ve worked for the year and figure out when you arrived or will arrive at 1,000 hours; (2) ask your employer for benefits in a written communication stating that you’ve reached or will reach 1,000 hours (3) contact an attorney if you think you are entitled to benefits.
This answer is provided for your information only to help you understand some of your legal rights. It should not be relied on as legal advice because it is not a substitute for the full consultation and advice of an attorney. Nothing contained in my comments constitutes the establishment of an attorney-client relationship.