Line Contractor

Transformer Safety


Upon completing this training, the employee will be able to:

  • Explain the dangers associated with working on transformers
  • Identify dos and don’ts associated with transformer works
  • Describe the basic safety precautions to abide by when working with transformers

Transformers are designed to change voltage at given ratios and can do so at all voltage levels unless damaged. As a result, working on transformers can be extremely dangerous.

To conduct work on a transformer, you must be familiar with how it operates and be properly trained for the type of work expected.

When working on transformers, always assume that they are energized until the primary and secondary leads have been disconnected. If you are installing and connecting a transformer, always make the ground and neutral connections first, then make any secondary connections. Always make the primary connection last. When uninstalling a transformer, remove the connections in the opposite order.

When raising or lowering a transformer, be sure that anyone standing on the ground stays clear of the device. There must be safe climbing space available on poles where transformer stations are being built.

Never touch the casing of a transformer or fuses on the high-voltage side of the device. Only open it with live line tools. Also, use live line tools when connecting the primary side of a transformer. Remember that appropriate rubber insulating personal protective equipment must be worn or isolating gear used.

Never change taps on an energized transformer unless the device is specifically designed to do so. When changing a transformer in a bank, make sure you check the nameplates for polarity, voltage and impedance to ensure the bank will function properly.

If you are working on a transformer where multiple transformers feed into the same secondary, place appropriate signage below the secondary to warn others that the possibility for feedback exists.

It is important to be cognizant of the weight of the transformer equipment. You need to make sure that any equipment used to raise or lower the transformer is capable of safely handling the weight. Likewise, ensure that any pole or object that the transformer is being installed on is also capable of bearing the load.

Discussion Questions

  • What are transformers designed to do and how does this relate to their dangers?
  • When should you assume a transformer is energized?
  • In what order should you make connections when installing a transformer?
  • In what order should you make connections when uninstalling a transformer?
  • With what should you open the fuses on the high-voltage side of a transformer?
  • When can you change taps on an energized transformer?
  • When you are changing a transformer in a bank, what should you check the nameplates for?
  • What should you do if you are working on a transformer where multiple transformers feed into the same secondary?

Stay Informed Join our Newsletter

Having trouble finding time to sit down with the latest issue of
ELECTRICAL CONTRACTOR? Don't worry, we'll come to you.