Workers operating under the Blue Book agreement voted to accept the employers final offer, which sees pay across all grades rise by 2% in January.
Rates will then rise again the following year by 2.3% and then 3.5% from January 2015.
It is an important deal for contractors who expect to see workloads and employment rise in the industry as construction of both gas-fired and nuclear power stations gets underway.
Skilled trades like welders, pipe fitters, steel erectors, insulation engineers, scaffolders and electricians will see their basic hourly rate rise to £15.25 in 2013, £15.60 in 2014 and £16.10 in 2015.
There are changes to other benefits such as 10 days for bereavement leave and better terms for redundancy plus uprating of travel and lodging allowances.
Phil Whitehurst, GMB national lead organiser for construction, said “GMB engineering construction membership had a very hard decision to make in what are very lean times and they have made a collective decision to accept the deal.
With publication today of the Energy Bill these are the skilled workers the nation will rely on to build our new generation of power stations.
He added that for industrial stability it was essential that all employers recognised the necessity of the universal usage of the national agreement on all engineering construction sites like new power station sites.
“There can be no further attempts to undermine it as happened at Lindsey and if there are these will be firmly resisted,” he warned.