Newark, Sept. 29- City policemen ringed the Essex County Jail here tonight as some of its inmates rioted, smashing equipment, breaking windows and setting a fire.

The prisoners seized long benches on which they used to sit in the daytime and used them as battering rams to damage the prison’s west wing and hold off guards.

The inmates were under control at 10 P.M. in emergency arrangements but they were not in their cells. Warden Francis A. Troy arranged to have groups of men shuttled under armed guards to the Essex County Penitentiary in a move to take pressure off his beleaguered staff.

Fifty-one men had been transferred to the penitentiary in Caldwell by midnight and Warden Troy hoped to have 120 men out by morning.

The outbreak began at 8 P.M. when 178 men who were on an open floor in the wing were ordered into their cells for the night. They refused to go, shouted threats and became “very violent,” a spokesman for the warden said.

At the same time, prisoners in the east, north and south wings became unruly and created “undue noise,” he said. The west wing, the prison’s oldest, was built in 1895.

There were 499 men in facilities intended for 375 at the time of the outbreak, Warden Troy said.

Some of the men climbed to the third tier in their cell block, punched a hole in the tin roof and set fire in a space under it.