The short version
A data center build feels like a long turnaround that never fully ends: early starts, long weeks near deadlines, lots of trades in the same rooms, and strict security. What's different is the length. One campus can keep a crew working for years.
The schedule
Most sites run five or six ten-hour days. As a data hall gets close to its ready-for-service date, it's common to go to six twelves, and some crews work seven days for a stretch. Ask about the schedule during commissioning, not just the normal week, because that's when the hours climb.
A normal day
The day usually starts with a safety huddle and a plan for the day. QA/QC walks the areas where work is being inspected or turned over, writes up issues in the GC's software, and meets with the trades and the commissioning agent. Afternoons tend to be paperwork: closing items, updating packages, planning tomorrow's inspections.
Getting in the gate
Expect a background check, a drug test and a safety orientation before your first day, and a photo badge after. Many owners don't allow phones or cameras past certain points, and some don't allow them on site at all. Plan for how your family reaches you during the day.
Who you answer to
The owner (the tech company) sets the rules and signs off. The general contractor runs the job. The commissioning agent tests and witnesses for the owner. Subs do the work. QA/QC usually sits with the GC or the owner's rep, and you'll work with all of them every day.
The pace
Several trades often work in the same hall at the same time, and every date works back from when the hall is handed over. It's less hazardous than a refinery, with no hydrocarbons or H2S, but there's more energized electrical gear than most plant people are used to. Electrical safety rules are enforced hard.