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Are you sure to buy “ECODESIGN” transformers according to regulation EU N.548/2014? Some local manufacturers have marketed transformers declared as “ECODESIGN” that are not compliant.


Regulation EU 548/2014 of 21st May 2014 (hereinafter the Regulation) defines the Ecodesign requirements (mandatory) in relation to small, medium and high power transformers. It was issued as part of the implementing measures required by the European Directive 2009/125/ EC of 21st October 2009, which forbid to place on the market or put into service in the EU low efficient products.

Specifically, the Regulation sets out maximum levels of load and no-load losses (with zero tolerance) of transformers for different levels of rated power. Two different timeframes have been foreseen (1st July 2015 and 1st July 2021) to be respected, depending to date of placing on the market of the transformers.

Under the aforementioned Regulation, starting from 1st July 2015, it is prohibited the marketing of transformers with losses greater than those set, except for special applications. To be noted that, being the Regulation a compulsory legal instrument and not a standard, the non-compliance of those prescriptions is a violation of the law [1].

[1]: A Regulation is a legal act of the European Union that becomes immediately enforceable as law in all member states simultaneously. The legal basis for the enactment of regulations is Article 288 of the Treaty on the Functioning of the European Union: « A regulation shall have general application. It shall be binding in its entirety and directly applicable in all Member States » (art. 288 TFUE).


TESAR, according to the Regulation and to its policy always aimed to “energize the world cleanly”, has designed the new range “Ecodesign”, combining successfully in a single product the demands of energy efficiency and reduced environmental impact.

In order to improve the quality of its products, a transformer "Ecodesign" TESAR (Power 630 kVA and ratio 20/0.4 kV) was compared with two transformers of the same declared features, manufactured by domestic competitors (Transformer A and B).

These transformers were tested in accordance with IEC-60076-11 (routine tests) at TESAR testing room. To validate these data, some tests (measurement of load losses and load and resistance measurement) were also repeated on transformer B at CESI laboratories, test report n. B5017187 dated September 03, 2015. The dimensional measurements on transformers A and B have also allowed a rough reconstruction of their designs.

Below the pictures of the transformers and two tables that show the values of the losses ratified by the Regulation and the data indicated on the rating plates.

Ecodesign Transformers Comparison


Ecodesign Transformers Comparison

Reference values of regulation EU No. 548/2014


Ecodesign Transformers Comparison

Rating plate data

Ecodesign Transformers Comparison


The examination of the results, considering the requirements of Regulation EU 548/2014, leads to the following considerations:

  • TESAR transformer is the larger and heavier and it is the only one that meets all requirements, both for no-load and load losses, with a margin of over 3%.
  • Transformer A does not respect no-load losses, for which the deviation is 11%. Load losses are higher than prescribed values of about 1%. The weight is lower approximately of 8% compared to that declared.
  • Transformer B is the smallest and the lightest of the three. The losses measurement, carried out at CESI, shows that, while the no-load losses have been met, the load losses are significant higher than those stated (about 19%) and also higher than the losses B established by regulation (deviation equal to 10.6% compared to 7600 W). The weight is less than that declared by about 15%.

Therefore it is necessary a special attention in the purchase of Ecodesign transformers, because in the market there are a lot of transformers which, although declared as "Ecodesign", are not compliant with Regulation EU 548/2014.


[1] Ecodesign regulation, EU No. 548/2014, May 2014
[2] European Directive 2009/125/ EC, October 2009
[3] IEC 6076-11, Power Transformers – Part11: Dry-type transformers
[4] Test report No. B5017187 at Cesi Laboratory, September 2015