The Solar Industry Foundation, a business group, says there were 143,000 solar industry workers in the U.S. as of late 2013, and that the fastest growing category is installers, up 22% or 12,500 overall.

Depending on the municipality and circumstances, California contractors use electricians or laborers for such installations.

So it's not a surprise that competition for work would lead to arguments, which is what has happened at a private school's new campus in San Mateo, Calif. The dispute broke out even though the project general  contractor, Devcon Construction Inc., Milpitas., had signed a project labor agreement with the San Mateo County Building Trades Council.

Devcon had awarded the solar panel installation contract for the school to San Francisco-based Luminalt Solar Energy Systems, which chose to use the laborers.

That provoked San Mateo-based Local 617 of the International Brotherhood of Electrical Workers to complain to San Mateo City Council members.

“Our electricians union came to us and said, '[the contractor] didn’t abide by the agreement,'” San Mateo City Councilman David Lim says. “I asked the manager for Devcon, ‘Did you honor the agreement?’ He said, ‘No. It came up at the last moment.’”

Devcon Construction declined to comment on the project. Controller Bret Sisney told a local newspaper that his company followed the project agreement. Sisney said unions could have requested a meeting once the solar component was added, the San Mateo Daily Journal reported.

Similar disputes have broken out in other states. Last year in Massachusetts,  where legislation had been passed to foster solar power and jobs in the state, union electricians were still butting heads with solar contractors.

Devcon Construction subcontracted the solar panel part of the job to San Francisco-based Luminalt Solar Energy Systems, which chose to use the laborers' union workers from San Mateo County and San Francisco.
Construction of the Nueva School's eco-amicable 2.7-acre campus began in early 2013, and is expected to be mostly completed in time for the upcoming school year.

For Lim, the dispute wasn’t a jurisdictional issue.

“If you sign an agreement with our building trades council, you have to honor that agreement,” Lim says.

But Luminalt chief executive Jeanine Cotter disagreed with at least part of the councilman’s explanation.

“We’re just a solar panel contractor…This is just a jurisdictional dispute, it’s not with the contractor,” she says.

Still, Devcon and Luminalt already have responded to that dispute over jurisdiction by meeting with the trades council and subsequently hiring a few union electricians to help with the solar panel installation.

Officials of both unions could not be reached for comment.

Lim defended the subcontractor. “Luminalt is an upstanding company, they got caught up in it—they had no idea the PLA hadn’t been followed,” Lim says.