A Crofton substation operator was accidentally electrocuted Friday evening while working on a transformer in Bethesda, Montgomery County police said.

Leonard Russell Ainsworth, 40, of Cambridge Drive died after he came into contact with a high-voltage conductor atop the transformer at a Potomac Electric Power Co. substation in the 4900 block of Del Ray Avenue near Old Georgetown Road.

An employee of Pepco for four years, Mr. Ainsworth was preparing the transformer to be returned to service after it was decommissioned for a paint job, a company spokeswoman said yesterday.