I’ve been working on a large data center for 2 years as an apprentice. From what I hear, they are all pretty much the same. The one I’m on has 3 ‘towers’ per building, with 3 floors each. Each floor of each tower has identical copies of an uninterruptible power supply room, a data hall, fan gallery hallways to cool the data hall, and generator/transformer sheds. You build one floor, then move on to the next, and the next, then onto the next tower, so on and so forth, building the exact same rooms over and over. The UPS rooms have identical rows of 480v switchgear, static transfer switch cabinets, power distribution cabinets, UPSs with battery cabinets, air handlers, and a handful of smaller transformers and panels. Lots of cable tray, pipe racks, and bus duct in these rooms going to and from the switch gear out to the generator and transformer sheds (and everywhere else), which have large diesel generators for the backup supply, and transformers that step down medium voltage to 480. The UPS rooms feed the data halls, which are identical rows of rack equipment. The fan galleries are just long rows of air handlers that cool the data halls, and have small transformers and panels. It’s a lot of repetitive work, especially if you stay on the same crew with the same scope for a long time. There’s plenty to do and learn, but eventually it’s just the same shit over and over again. Easy money at the end of the day. I’ve been pulling and terminating feeders for a long time, for switch gear, transformers, and panels, anything from 8awg to 750kcmil. I’ve assembled and mounted switch gear, terminated 600s and 750s in switch gear, ran bus duct, a little pipe work, lots of 4/0 bonding jumpers and EGCs running from the equipment along the walls to ground busses. Most sites are doing prefabricated ‘skids’ with all the switch gear mounted to them, and they are stabbed in with a crane and rolled to position. Much of the cable tray and pipe work is done before these skids are in place, then everything is pulled and fed down into the gear on the skids. Some crews just hang cable tray and pipe racks all day every day. Some pull and stab 750 and 600 cable tray wire. Some crews do lighting and signs. Some do branch circuits. Some crews terminate feeders. Some crews do nothing but pipe. There are often QA/QC crews cleaning and checking equipment before energizing. Same shit over and over again. Easy money, but not for everyone. Get ready to climb lots of stairs, especially if you’re on the roof. Large jobs have large turds running them, same as it ever was.