Anthony William John Daniel, trading as Towy Valley Fabrications was prosecuted by the Health and Safety Executive (HSE) following the incident at Plasbach Farm in Ffairfach, near Llandeilo on 15 April 2011.
Ammanford Magistrates' Court heard that Daniel Elliot, 24, from Nottingham was an inexperienced steel erector and had been employed by Mr Daniel to assist in the construction of a new pitched roof between existing buildings on the farm.
The work involved the demolition of a small existing roof, and the installation of new steel frames between the buildings. Mr Elliot was standing on the roof of one of the existing buildings and pulling up an electrical extension cable, when he stepped backwards onto a fragile PVC skylight and fell 5.5m to the ground below.
Mr Elliot broke two bones in his spine in the fall, fractured his pelvis and suffered an injury to his arm which required stitches. He is no longer physically able to work as a steel erector.
The court heard that the defendant had failed to notify the HSE of the incident at the time.
The HSE was eventually made aware of the incident by Mr Elliot's mother and a subsequent investigation was launched. It found that Mr Daniel had failed to properly plan and supervise work at height activities, and ensure that appropriate measures were in place to control the associated risks.
Anthony William John Daniel, trading as Towy Valley Fabrications of The Brambles, Llanwrda, Carmarthenshire, pleaded guilty to breaching Regulation 3(1) the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995. He also pleaded guilty to breaching Section 2(1) of the Health and Safety at Work etc Act 1974.
He was fined £6,500 and ordered to pay £2,651 in costs.
Speaking after the hearing, HSE inspector Phil Nicolle said: "Anthony Daniel undertook the erection of a steel framed agricultural building with little understanding of the need for the safety measures that routinely apply to such construction work. He employed an inexperienced worker and exposed him over the course of several days, to risks of a fall from height ultimately resulting in the fall of 5.5m which caused serious injury. Mr Daniel then failed to notify HSE of the incident.
"There is no room for complacency when undertaking work at height in the construction industry. The risks are well known. Employers must ensure the work at height is planned, managed and supervised by competent people and where they are undertaking any of those roles themselves that they are competent to do so."