Accurate torque values mean less time spent on O&M later

During racking and panel installation at large-scale solar projects, thousands and thousands of bolts must be fastened at just-the-right torque level to ensure the array stays together. Too tight and the bolts can damage the long-term structural integrity of the system. Too loose and things could wiggle out of place. That’s why proper torquing at installation is an important factor in successful operations and maintenance.

Mark Kelly, group manager of product marketing at Milwaukee Tool, said he has seen audits of solar projects that show a broad distribution of torque values, with some sites having upward of 80% of bolts at incorrect levels despite passing quality checks.

“Incorrect torquing is a common problem on solar projects,” Kelly said. “The traditional two-step method, which involves first fastening the bolt with an impact wrench and then manually torquing it with a click-style torque wrench, is highly dependent on operator technique. This can lead to poor torque repeatability and significant over-torquing.”

There are various tools and techniques that can bring consistency to torquing. Torque sticks absorb additional impacts when they reach a preset torque level. Some installers avoid using battery-powered tools to prevent under-torquing due to low battery voltages. Still more technicians rely on markers to record a bolt’s tightness to see if it moves over time.

All of these suggestions aren’t 100% reliable, though. Milwaukee aims to improve this area for solar installers. The company’s M18 FUEL impact wrench is available with TORQUE-SENSE, a sensor that helps with repeatable torque values.

“This tool provides repeatable torque results, ensuring consistent and reliable fastening, which is crucial for the quality and safety of solar installations,” Kelly said.

It’s not a physical add-on to the existing impact wrench like a torque stick, as all the brains are in the impact wrench itself. Instead of a two-step process, one tool delivers the needed torque value.

Milwaukee also offers ONE-KEY technology, a platform that records every trigger pull, capturing data such as target torque levels and error reports. The recorded data helps identify potential issues early, allowing for proactive maintenance and reducing downtime.

Kelly said access to ONE-KEY data can be customized based on a project’s needs, but typically individual installers, EPCs and asset managers can see the torque numbers.

“EPCs can access data to help ensure torque control settings are being utilized and to manage tool usage across multiple projects. Project managers can track tool performance, utilization and maintenance schedules to optimize project efficiency,” he said. “Quality assurance teams can use the data to verify that installations meet required standards and to generate reports for auditing purposes. Individual tool owners can customize settings, track tool location and monitor usage to prevent loss and ensure proper maintenance.”

Using automated tools like these takes away some of the guesswork around the necessary maintenance on a solar project’s thousands of bolts. Everything must still be properly checked throughout a system’s lifespan, but at least project owners know the bolts were torqued correctly the first time.

“Ensuring accurate and repeatable torque application is crucial for the safety, reliability and longevity of solar projects,” Kelly said.