The Prince George's County Council, following the lead of federal and state governments, voted yesterday to require that minority firms receive 10 percent of the county's contracts.

The bill, passed unanimously by the council and supported by groups ranging from the county Chamber of Commerce to the NAACP, also requires that contracts of more than $5,000 be granted by competitive bidding. County Executive Lawrence Hogan said through a spokesman yesterday that he will sign the measure.

Glenarden council member Floyd Wilson, who introduced the bill, said it would "encourage minority contractors who may not perceive Prince George's as a place to do business because they haven't been able to in the past. Most contracts with black firms have been for trash collection, but we've got architects, contractors, builders."

The bill requires that 10 percent of the dollar value of the county's purchase contracts go to "economically disadvantaged minority business enterprises" and designates a procedure to determine who is economically disadvantaged. Minorities are defined as black, Hispanic, and Asian Americans, American Indians, Eskimos and Aleuts (native Americans) and females. The firm or its stock must be at least 51 percent owned by minorities and its management and daily operations controlled by minorities.

In 1978, the state of Maryland passed similar legislation covering most state contracts.

Scull Introduces Three Bills To Aid Montgomery Employes

Three measures aimed at helping county employes were introduced yesterday by Montgomery County Councilman David Scull, who has been under attack by county workers recently for another bill that would cap their salaries.

Under one bill, county employes, rather than managers, would choose who should receive cash bonuses for exceptional work. Another proposal would allow county workers to receive the salary and title of a vacant position if they could show they have assumed the duties of the vacant slot in addition to their regular work.

Citing a recent county study showing a severe shortage of child-care facilities, Scull also introduced a bill that would enable county employes to design a fringe benefits package that includes payments for day care.

Under the proposal, the county's 5,400 employes could receive up to $2,000 in nontaxable day-care expenses by reducing by $2,000 what the county now pays for their health insurance or retirement pension.

Benefits constitute 32 percent of the average county employe's income. Scull said his "cafeteria-style benefits plan" would enable county employes to choose only those benefits they need. Because the employe would substitute one benefit for another, Scull said, the plan would not cost the county extra money. A county report released last month showed only 24 percent of the 30,000 children in the county under age 9 with working mothers were being supervised in licensed day-care centers.

He also introduced a bill designed to help parents collect child-support payments from spouses who work for the county. Under the bill, a parent would prove that support money is owed by presenting a separation agreement or court order. The county would deduct the debt from the spouse's payroll check. Scull said that studies have shown that 80 percent of the parents who owe child support stop paying after two years.

Yet another Scull bill yesterday would prohibit the purchase of ammunition in the county unless the buyer can show a valid gun-registration certificate.

Scull said his bill was inspired by the efforts of tiny Friendship Heights, which last year passed a similar ban on bullets.

"The whole point of this is not to stop criminals from buying guns and ammunition illegally," Scull said. "We don't have any illusions of doing that." Rather, he said, the bill would increase gun registrations, as he said state police have found that this helps solve gun-related crimes.

Localities are preempted by state law from enacting handgun control legislation and the General Assembly this year decided not to lift that preemption.