Samuel Wright Maxwell, 46, was employed at Cooper B-Line's factory in Highbridge. On 17 May 2013, he was working on a roof when he fell through the skylight and on to the concrete floor of the rack assembly area, 7 m below. He died shortly afterwards.
Taunton Crown Court was told that maintenance staff had permission to work on the roofs and did so regularly without proper precautions to prevent them falling.
The Health and Safety Executive (HSE) found the company's generic risk assessment was inadequate and did not identify the risks and control measures necessary for employees working at height.
Cooper B-Line pleaded guilty to breaching s 2(1) of the Health and Safety at Work Act. It was fined £210,000 and must pay costs of £36,494.
HSE inspector Annette Walker said: "In this case a confusing system of work had developed and unintentionally encouraged dangerous methods."
