Two north Wales companies have been fined a total of £31,000 after a teenager died of electrocution.
Miall Roberts died in May 2004 while laying concrete foundations
The mother of Miall Roberts, 19, of Bala, Gwynedd, said the fines could have been higher, but the end of the case meant the family could move on.
He was laying concrete foundations when he died at Bala in May 2004.
At Mold Crown Court RL Davies & Son was fined £25,000 with £15,814 costs, and Permanent Flooring was fined £6,000 with £12,000 costs.
Mr Roberts died when machinery struck an overhead electricity cable, and a colleague escaped with minor injuries.
RL Davies and Son, of Colwyn Bay, Conwy, and Permanent Flooring, of Bagillt, Flintshire, both admitted health and safety at work charges.
Judge Dafydd Hughes said the former Welsh Development Agency - which was developing a new food factory at Bala - and Scottish Power had a responsibility and should have ensured that the power lines crossing the site were removed before work started.
The judge said if they had insisted on the cables being removed before work started on the new food factory for Gwynedd Confectionary then the tragedy would never have happened.
Speaking outside the court, Mr Roberts' mother Janice said: "I am not very happy with the fines, I thought they might have been higher, but after saying that you cannot put a price on a life."
Full risk assessment
"Today has been a very long day and the whole matter could have been dealt with sooner because all we have had for the past three years is the accident."
The time had been difficult for the whole family, she added.
"I'll remember Miall as someone mischievous, full of fun, always happy, who enjoyed being with the girls," she added.
The Health and Safety Executive warned construction companies to carry out proper risk assessments on site.
HSE inspector Chris Wilcox said: "Each year there are around 1,000 incidents involving electric shock at work, and about 30 of these have resulted in fatalities."
He said it was imperative that employers ensured their staff and contractors were protected by carrying out a full risk assessment of the site before work starts.
"Household voltages are enough to kill, but in this case the voltage involved was nearly 50 times greater.
"Overhead power lines can be switched off if the operators are given sufficient notice, but if this isn't possible, they should be consulted on safe systems of work," he added.