Garland Power & Light recently published the following safety message.
Neighborhoods with underground utilities have pad-mounted transformers. These are the green metal boxes typically located within public utility easements. Please maintain a 12-foot clearance in the front of the unit and 3-foot clearance on the sides and back.
For your safety, do not touch or make contact with a pad-mounted transformer, and do not allow children to play on or near the transformer.