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Transformer Safety: Installation & Maintenance Best Practices

Transformer Safety: Installation & Maintenance Best Practices

High-voltage capacity equipment like transformers can be hazardous if not handled with care. This is why it is essential to always follow proper safety procedures during the installation, normal operation, and maintenance of transformer units. If these safety precautions are neglected, disastrous consequences like injury, emergency shutdown, or total system breakdown may occur, all of which jeopardise the facility’s operation. By ensuring proper installation and keeping the transformer’s design in mind, organisations can better maintain a safe environment for their employees and components of the transformer equipment regardless of its system type or manufacturer.

5 Safety Rules for Transformer Installation

Strict compliance with safety regulations regarding transformer installation is crucial for two reasons: to protect the transformer unit and the employees and to secure the transformer’s warranty validity. Failure to comply could lead to damaging the entirety of the electrical installation as well as voiding the warranty if the installation deviates from the manufacturer’s instructions.

Below are the five core guidelines to safely install any transformer equipment.

1. Engage a certified electrical engineering provider for the installation

Although installing a transformer seems simple enough, engaging with a mechanical and electrical engineering company is always recommended to ensure the process is guaranteed to be safe and completed as per the manufacturer’s instructions. The same applies to any additional interferences on the transformer unit down the line. These companies can also perform electric transformer testing.

2. Ensure correct selection of nominal power

When choosing the nominal power of the transformer, it is important to first consider input voltage fluctuation of up to +10%, similar to the fluctuation of the total power, which could overload the transformer. Therefore, a +10% intolerance needs to be included in the basic calculation of nominal power.

3. Check the load’s power factor

It is crucial to check the power factor of the load so that it is included in the apparent power (e.g. economy and fluorescent lamps, LED, HQI, motors, and so on) when calculating the power of the transformer. This avoids the common error of selecting the transformer based on the active power instead of the apparent power.

4. Check the input-output voltage as per the line’s maximum load

The maximum load of the line the transformer is connected to has an input-output voltage that needs checking when the circuit begins operation. Doing so determines if the transformer is overloaded, which takes place once the drop in voltage is above 6% of the nominal. In such cases, the transformer must be replaced with another with a higher nominal power. In contrast, if the drop is below 6%, the transformer is suitable for the application.

5. Install adequate ventilation for the transformer

During the installation process, it is important to have adequate air ventilation according to the transformer’s ambient temperature limits. Should this limitation not be mentioned, consider following the 25°C ambient temperature as per the IEC EN 61558-1, section 8.1.ο.

Best practices when doing transformer maintenance work

Once installation is complete, end users must regularly do maintenance on the transformer to ensure its optimal performance and longevity. The following are some safety precautions to keep in mind when caring for your transformers.

  • Always assume that a transformer is energised until the primary and secondary leads are proven to be disconnected.
  • De-energize and tag out the transformer and shut down its circuit before doing any maintenance work. This ensures no current leakage or electrical continuity between the system and the current source.
  • Keep the transformer and its components dry at all times and free from moisture or water, and ensure that this is the case before maintenance.
  • Use all the necessary rubber-insulating personal protective equipment and isolating gear.
  • Place tools and spare parts like nuts and bolts at a safe distance when doing maintenance to prevent them from touching or falling into the transformer.
  • Change taps on an energised transformer only if the unit is specifically designed for it.
  • Should there be a need to transport the transformer, be sure that the equipment used to raise or lower the device is rated to safely handle its weight. Likewise, ensure that the object or pole to which the transformer will be moved can bear its load.


Safe installation and handling of transformers is key to avoid damaging the device and ensuring the safety of end users. Aside from the important factors to consider when selecting an electric transformer, it is also important to remember and follow the safety guidelines mentioned in this article or directly specified by the manufacturer, especially if deviating from their instructions could risk your warranty.