Considerations for Safe Installation of Transformer

Considerations for Safe Installation of Transformer

5 rules for safe installation of transformer

Issues related to the safe installation of the transformer, strict compliance with the safety regulations during the installation and operation of the transformer is an issue to be considered carefully for two main reasons:

First of all, to protect the electrical equipment of the installation and the entire electrical installation, but most importantly to protect human life from accidents.

Secondly, to ensure the validity of the warranty, which expires if the necessary procedures are not followed during the installation and operation of the transformer.

Below we analyze the five main safety guidelines that must be strictly followed during the installation of a transformer.


1. Installation must be done by a certified electrician.

Although transformer installation may seem easy and simple, in reality, as we have seen in our experience, it can be very dangerous if not done by a certified electrician. The same applies to other future interventions on the transformer.

2. Choosing the right rated power

During the selection of the rated power of the transformer, fluctuations in the input voltages up to +10% must be taken into account, causing the same fluctuation in the total power and may cause overloading of the transformer. Consequently, a tolerance of +10% must be added to the basic calculation of the rated power.

3. Control of the power factor of the load

To be included in the calculation of transformer power as apparent power (VA), the power factor of the load needs to be checked (eg Fluorescent lamps, economy lamps, HQI, LED, motors, etc.). In this way, the common error of choosing a transformer according to the active power (W) of the load instead of the apparent (VA) which actually overloads the transformer is avoided.

4. Checking the input-output voltage on the line of the maximum load

Controlling the input – output voltage at the maximum load of the line to which the transformer is connected is important when the circuit starts to work. The transformer is overloaded if the voltage drop is more than 6% of the nominal (when the supply voltage is nominal). In this case, it is necessary to replace the transformer with a larger rated power. When the voltage drop falls below 6% of the nominal, it can be ensured that the correct transformer has been selected.

5. Convenient sale of transformer

When installing a transformer, adequate and adequate ventilation must be provided within ambient temperature limits. If this limit is not indicated on the transformer marking, an ambient temperature of 25°C must be taken into account (according to standard EN 61558-1, section 8.1.ο). The heat radiated is proportional to its power.

Installation of heat dissipating components under the transformer should be avoided (in case of vertical installation). Heat sensitive components such as electronic circuits must be properly assembled.

Unfortunately, it is common practice to install transformers in airtight commercial boxes, which clearly hinders proper ventilation. As a result of this practice, the transformer is destroyed, as the generated heat constantly raises the ambient temperature and drags the transformer to a constant overheating.