Transformers must be used on building sites to convert power from the main source from 240 volts, which is the standard non-industrial use, to 110 volts. This reduced voltage makes them safer in the event of burnout, damaged cables, exposure to water, etc.
Site transformers are also called junction boxes. They can provide power to lots of different power tools at once without burnout. All the transformers and leads should be yellow.
The ways of lifting these can vary. Some transformers have lifting points, as shown in the image. But, as with anything with lifting points, the certificates should be in date.
Some sites don’t even allow the lifting points to be used. They prefer the transformer to be slung using lifting chains or slings. The ones without lifting points have to be slung, regardless.