In recent months Incident Prevention has received several questions about underground (UD) padmount transformers, so in this installment of “Voice of Experience,” I’d like to take the time to cover the general aspects of these types of transformers.
To begin, there are a few different types of single-phase and three-phase UD padmounts: live front with exposed live primary parts, 600-amp bolt-on elbows and loop feed with bushings and elbows. All of these transformers are available in several voltage ranges.
The proper PPE must be worn when an employee is opening, entering and working on energized transformers. This includes a rated hard hat, eye and face protection, rubber gloves, heavy leather boots and arc-rated FR clothing. Additionally, all PPE must be worn by any employee exposed to energized equipment and cables until the transformer has been de-energized and checked for the absence of voltage, and all exposed parts have been properly grounded.