EN    EN  
 EUROPEAN 
COMMISSION  
Brussels, XXX   
[…](2013) XXX  draft 
  
COMMISSION REGULATION (EU) No …/.. 
of XXX  
on implementing Directive 2009/125/EC with regard to small, medium and large power 
transformers 
 EN 2   EN COMMISSION REGULATION (EU) No …/.. 
of XXX 
on implementing Directive 2009/125/EC of th e European Parliament and of the Council 
with regard to small, medium and large power transformers 
THE EUROPEAN COMMISSION,  
Having regard to the Treaty on the Functioning of the European Union,  Having regard to Directive 2009/125/EC of the Eu ropean Parliament and of the Council of 21 
October 2009 establishing a framework for th e setting of ecodesign requirements for energy-
related products ( 1 ) and in par ticular Article 15(1) thereof,  
After consulting the Ecodes ign Consultation Forum,  
Whereas: 
(1) The Commission has carried out a preparator y study that analysed the environmental 
and economic aspects of transformers. The study was developed together with 
stakeholders and interested parties from the Community and the results have been 
have made publicly available. Transfor mers are considered as energy related 
products within the meaning of Arti cle 2 (1) of Directive 2009/125/EC. 
(2) The study showed that energy in the use phase is the mo st significant environmental 
aspect that can be addressed through product design. Significant amounts of raw 
materials (copper, iron, resin, aluminium)  are used in the manufacturing of 
transformers, but market mechanisms seem to be ensuring an adequate end-of-life 
treatment, and therefore it is not necessary to establish related ecodesign 
requirements. 
(3) Ecodesign requirements set out in Annex I appl y to products placed on the market or 
put into service wherever they are instal led. Therefore such requirements cannot be 
made dependant on the applicati on in which the product is used. 
(4) Certain categories of transformers should not  be covered by this Regulation, due to 
their specific function, transport or instal lation restrictions.. The energy consumption 
and saving potential of such transforme rs is negligible compared to other 
transformers.  
(5) Regulatory concessions are granted because of the weight limitations for mounting 
transformers on utility poles. In order to avoid misuse of transformers specifically 
manufactured for pole-mounted operation, they  should include a visible display “For 
pole-mounted operation only”, so as to f acilitate the work of national market 
surveillance authorities. 
(6) Regulatory concessions are granted to tran sformers equipped with equipment capable 
of performing voltage regulation functions to integrate distribut ed generation from 
renewable sources into the distribution grid. Such con cessions should gradually be 
phased out as this emerging technology ma tures and measurement standards become 
available to separate the losses associat ed to the core transformer from those 
associated to the equipment performing additional functions.    EN 3   EN (7) Ecodesign requirements for the energy perf ormance/efficiency of medium power 
transformers and for the energy efficiency of large power transformers should be set 
with a view to harmonising ecodesign re quirements for these devices throughout the 
Community. Such requirements would also contribute to th e efficient functioning of 
the internal market and to improving Memb er States’ environmental performance. 
(8) Establishment of ecodesign requirements fo r medium and large power transformers 
is also necessary to incr ease the market penetration of technologies and design 
options improving their energy performan ce/efficiency.. Total losses of the 
transformers fleet in the EU27 in 2008 amounted to 93.4 TWh per year. The cost-effective improvement potential through more efficient design has been estimated in 
about 16.2 TWh per year in 2025, which corresponds to 3.7 Mt of C02 emissions. 
(9) It is necessary to provide for a staged en try into force of the ecodesign requirements 
in order to provide an a ppropriate timeframe for manuf acturers to redesign their 
products. Time limits for the implementation of those requirements should be set taking into account impacts on the costs for manufacturers,  in particular small and 
medium size enterprises, while ensuring tim ely achievement of the policy objectives. 
(10) To allow an effective implementation of the regulation, National Regulating 
Authorities are advised to take account of the effect of minimum efficiency 
requirements on the initial cost of the transformer and to allow for more efficient transformers than the regulation requires  if these are economically justified on a 
whole life cycle basis.  
(11) To facilitate compliance checks, manufacturers should be asked to provide 
information in the technical documentation referred to in Annexes IV and V to Directive 2009/125/EC. 
(12) The measures provided for in this Regulat ion are in accordance with the opinion of 
the Committee established by Article  19(1) of Directive 2009/125/EC. 
 
HAS ADOPTED THIS REGULATION: 
 
Article 1 
Subject matter and scope 
1. This Regulation establishes ecodesign requir ements for placing on the market or putting 
into service transformers with a minimum power rating of 1 kVA used in 50Hz electricity transmission and distribution networks or for industrial applications. The regulation is only 
applicable to transformers purchased afte r the entry into force of the Regulation.  
2. This Regulation shall not appl y to transformers specifica lly designed and used for the 
following applications: 
• Instrument transformers, specifically de signed to supply measuring instruments, 
meters, relays and other similar apparatus 
• Transformers with low voltage windings sp ecifically designed for use with rectifiers 
to provide a DC supply 
• Transformers specifically designed to be directly connected to a furnace EN 4   EN • Transformers specifically designed for of fshore applications and floating offshore 
applications 
• Transformers specially designed  fo r emergency mobile installations 
• Transformers and auto-transformers sp ecifically designed for 16.7 Hz railway 
feeding systems 
• Auto-transformers for 50 Hz railway feeding systems 
• Earthing or grounding transformers, this is , three-phase transf ormers intended to 
provide a neutral point for system grounding purposes 
• Traction transformers mounted on rolling stock,  this is, transformers connected to an 
AC or DC contact line, directly or through a converter, used in fixed installations of 
railway applications 
• Starting transformers, specifically designed for starting three-phase induction motors 
so as to eliminate supply voltage dips 
• Testing transformers, specifically designed to be used in a circuit to produce a 
specific  voltage or current for the pu rpose of testing electrical equipment 
• Welding transformers, specifically designe d for use in arc welding equipment or 
resistance welding equipment 
• Transformers specifically designed fo r explosion-proof and underground mining 
applications 
• Transformers specifically designed for deep water (submerged) applications 
• Medium Voltage (MV) to Medium Voltage  (MV) interface transformers up to 5 
MVA 
• Large power transformers where it is demons trated that for a particular application, 
technically feasible alternatives are not available or where th e minimum efficiency 
required by this Regulation cannot be ach ieved without entailing disproportionate 
costs associated to its trans portation and/or installation.  
Article 2 
Definitions 
For the purpose of this Regulation and its annexes the following definitions shall apply. 
(1) “Power transformer” means a static piece of apparatus with two or more windings 
which, by electromagnetic induction, transforms  a system of alte rnating voltage and 
current into another system of alternati ng voltage and current usually of different 
values and at the same frequency for th e purpose of transmitting electrical power. 
(2) “Small power transformer” m eans a power transformer with a highest voltage for 
equipment not exceeding 1 kV. 
(3) “Medium power transformer” means a power  transformer with a high voltage for 
equipment higher than 1 kV, but not exceeding 36 kV and a rated power equal or higher than 5 kVA but lower than 40 MVA.  
(4) “Large power transformer” means a power  transformer with a high voltage for 
equipment exceeding 36 kV and a rated power equal or higher than 5 MVA. EN 5   EN (5) “Liquid-immersed transformer” means a power transformer in which the magnetic 
circuit and windings are immersed in liquid. 
(6) “Dry-type transformer” means a power tran sformer in which the magnetic circuit and 
windings are not immersed in an insulating liquid.  
(7) “Pole mounted transformer” means a power transformer suitable for outdoor service 
and designed to be mounted on the suppor t structures of overhead power lines. 
(8) Voltage Regulation Distribution Transfor mer means a medium power transformer 
equipped with additional components, inside  or outside of the transformer tank, to 
automatically control the input or output volta ge of the transformer for on-load voltage 
regulation purposes. 
(9) “Winding” refers to the assembly of turns fo rming an electrical ci rcuit associated with 
one of the voltages assigned to the transformer.  
(10) Rated voltage of a winding (U r) is the voltage assigned to be applied, or developed at 
no-load, between the terminals of an untapped winding, or of a tapped winding 
connected on the principal tapping. 
(11) “High-voltage winding” refers to the winding having the highest rated voltage. 
(12) “Rated power” (S r) is a conventional value of apparent power assigned to a winding 
which, together with the rated voltage of  the winding, determines its rated current. 
(13)  “Load loss” (Pk) means the absorbed activ e power at rated frequency and reference 
temperature associated with a pair of windings when the rated current (tapping 
current) is flowing through the line term inal(s) of one of the windings and the 
terminals of the other windings are in s hort-circuit with any winding fitted with 
tappings connected to its principal tappi ng, while further windings, if existing, are 
open-circuited. 
(14) “No load loss” (Po) means the active power absorbed at rated frequency when the 
transformer is energised and the secondary ci rcuit is open. Peak Efficiency Index (PEI) 
means the maximum value of the ratio of the transmitted apparent power of a 
transformer minus the electrical losses to the transmitted apparent power of the transformer.  
Article 3 
Eco-design requirements 
Small power transformers, medi um power transforme rs and large power transformer shall 
meet the ecodesign requirements set out in Annex I.  
Article 4 
Form of the Implementing measure  
The Commission intends to propose a directly  applicable Implementing Regulation under 
Directive 2009/125/EC. The proposed Regulation is not expected to have a particular impact 
on the EU acquis. There are no overlaps with ot her Ecodesign regulations, as far as is known. 
Article 5 
Conformity Assessment 
Conformity assessment shall be carried out appl ying the internal design control procedure set 
out in Annex IV to Directiv e 2009/125/EC or the management system procedure set out in 
Annex V to that Directive.  EN 6   EN Article 6 
Verification procedure for market surveillance purposes 
When performing the market surveillance chec ks referred to in Directive 2009/125/EC, 
Chapter 3 (2), Member State authorities shal l apply the verification procedure set out in 
Annex III to this Regulation. 
Article 7 
Review 
No later than three years after the entry into force of the requirements for Tier 1 set out in 
Annex I of this Regulation, the Commission shall review them in the light of technological 
progress and present the results of this review  to the Consultation Forum. Specifically, the 
review will consider, at l east, the following issues: 
• The appropriateness of the levels set for th e specific Ecodesign requirements in Tier 
2 and the need to establish further Tiers for any type of transforme rs in the light of 
market trends 
• The availability of the materials necessary to meet such requirements 
• The possibility to set out minimum values of the Peak Efficiency Index for all 
medium power transformers, including t hose with a rated power below 3150 kVA 
• The possibility to separate the losses asso ciated to the core transformer from those 
associated with other components perfor ming voltage regulation functions, where 
this is the case 
• The appropriateness of esta blishing minimum performa nce requirements for single-
phase transformers, as well as for small power transformers 
• Whether concessions made for pole-m ounted transformers and for special 
combinations of winding voltages for me dium power transformers are still 
appropriate 
• The possibility of covering environmental im pacts other than energy in the use phase 
 
Article 8 
Entry into force 
The Regulation shall enter into force on the 20th day following its publication in the Official 
Journal of the European Union. 
The requirements set out in Annex I shall apply in accordance with the timetable provided for 
therein. 
This Regulation shall be binding in  its entirety and directly applicable in all Member States. 
Done at Brussels,  
 For the Commission 
 The President     EN 7   EN ANNEX I   
Ecodesign requirements 
1)Minimum energy performance or effici ency  requirements for medium power 
transformers 
Medium power transformers shall comply with the maximum allowed load and no-load losses 
or the Peak Efficiency Index (PEI) va lues set out in Tables I.1 to I.6. 
1.1) Requirements for three-phase medium power transformers with rated power 
≤3150kVA 
Table I.1: Maximum load and no-load losses for three-phase liquid-immersed  medium power 
transformers with the high-voltage winding rated ≤ 24 kV and the other winding rated ≤ 
1.1kV 
 Tier 1 (from 1 July 2015) Tier 2 (from 1 July 2021) 
RATED 
POWER (kVA) 
 Maximum 
load losses Pk 
(in Watts) * Maximum no-
load losses Po 
(in Watts)* Maximum load 
losses Pk 
(inWatts)* Maximum no-
load losses Po 
(in Watts)* 
25 Ck (900) Ao(70) Ak(600) Ao-10% (63) 
50 Ck (1100) Ao(90) Ak(750) Ao-10%(81) 
100 Ck (1750) Ao(145) Ak(1250) Ao-10%(130) 
160 Ck (2350) Ao(210) Ak(1750) Ao-10%(189) 
250 Ck (3250) Ao(300) Ak(2350) Ao-10%(270) 
315 Ck (3900) Ao(360) Ak(2800) Ao-10%(324) 
400 Ck (4600) Ao(430) Ak(3250) Ao-10%(387) 
500 Ck (5500) Ao(510) Ak(3900) Ao-10%(459) 
630 Ck (6500) Ao(600) Ak(4600) Ao-10%(540) 
800 Ck (8400) Ao(650) Ak(6000) Ao-10%(585) 
1000 Ck (10500) Ao(770) Ak(7600) Ao-10% (693) 
1250 Bk (11000) Ao(950) Ak(9500) Ao-10%(855) 
1600 Bk(14000) Ao(1200) Ak(12000) Ao-10%(1080) 
2000 Bk (18000) Ao(1450) Ak(15000) Ao-10%(1305) 
2500 Bk (22000) Ao(1750) Ak(18500) Ao-10%(1575) 
3150  Bk (27500) Ao(2200) Ak(23000) Ao-10%(1980) EN 8   EN *Maximum losses for kVA ratings that fall in be tween the ratings given in Table I.1 shall be 
obtained by linear interpolation. 
Table I.2: Maximum load and no-load losses for three –phase dry-type  medium power 
transformers with the high-voltage winding rated ≤ 24 kV and the other winding rated ≤ 
1.1kV 
 Tier 1 (1 July 2015) Tier 2 (1 July 2021) 
RATED 
POWER (kVA) 
 Maximum 
load losses Pk 
(in Watts)* Maximum no-
load losses Po 
(in Watts)* Maximum 
load losses Pk 
(in Watts)* Maximum no-
load losses Po (in 
Watts)* 
50 Bk (1700) Ao(200) Ak(1500) Ao-10%(180) 
100 Bk (2050) Ao(280) Ak(1800) Ao-10%(252) 
160 Bk (2900) Ao(400) Ak(2600) Ao-10%(360) 
250 Bk (3800) Ao(520) Ak(3400) Ao-10%(468) 
400 Bk (5500) Ao(750) Ak(4500) Ao-10%(675) 
630 Bk (7600) Ao(1100) Ak(7100) Ao-10%(990) 
800 Ak (8000) Ao(1300) Ak(8000) Ao-10%(1170) 
1000 Ak (9000) Ao(1550) Ak(9000) Ao-10%(1395) 
1250 Ak (11000) Ao(1800) Ak(11000) Ao-10%(1620) 
1600 Ak (13000) Ao(2200) Ak(13000) Ao-10%(1980) 
2000 Ak (16000) Ao(2600) Ak(16000) Ao-10%(2340) 
2500 Ak (19000) Ao(3100) Ak(19000) Ao-10%(2790) 
3150 Ak (22000) Ao(3800) Ak(22000) Ao-10%(3420) 
*Maximum losses for kVA ratings that fall in be tween the ratings given in Table I.2 shall be 
obtained by linear interpolation. 
Table I.3: Correction of load and no load lo sses in case of other co mbinations of winding 
voltages or dual voltage in one or both windings  (rated power ≤ 3150kVA) 
One winding with Um ≤ 
24 kV and the other with Um > 1.1 kV The maximum allowable losses in  Tables I.1 and I.2 can be 
increased by 10% for no load losses and by 10% for load 
losses  
One winding with Um = 36 kV and the other with Um ≤ 1.1 kV The maximum allowable losses in  Tables I.1 and I.2 can be 
increased by 15% for no load losses and by 10% for load 
losses  EN 9   EN One winding with Um = 
36 kV and the other with Um > 1.1 kV The maximum allowable losses indi cated in Tables I.1 and I.2 
can be increased by 20% for no  load losses and by 15% for 
load losses  
In case of transformers with one MV (Medium Voltage) winding and two voltages availabl e from a tapped LV (Low 
Voltage) winding, losses shall be calculated based on the higher LV voltage and shall be in compliance with the maximum allowable losses in Tables I.1 and 1.2. The maximum available power on the lower LV winding on such transformers shall be limite d to 0.85 of its nominal rated 
power.  Case of dual voltage on one winding  
 
If the full nominal power is available regardless of the 
combination of voltages, the levels of losses indicated in Tables I.1 and I.2 can be incr eased by 15% for no load losses 
and by 10% for load losses.  
In case of transformers with  one MV winding with two 
voltages available from a tap, the maximum available power on the lower MV voltage on such transformer shall be limited to 0.85 of its nominal rated power.    
Case of dual voltage on both windings The maximum allowable losses in  Tables I.1 and I.2 can be 
increased by 20% for no load losses and by 20% for load 
losses for transformers with dual voltage on both windings. The level of losses is given on th e basis that the rated power is 
the same regardless of the combination of voltages.  
 
1.2) Requirements for medium power tran sformers with rated power >3150kVA 
Table I.4: Minimum Peak Effici ency Index (PEI) values for liquid immersed  medium power 
transformers 
Tier 1 (01.07.2015) Tier 2 (01.07.2021) RATED POWER 
(kVA)  Minimum Peak Efficiency Index (%) 
4000 99.465 99.532 
5000 99.483 99.548 
6300 99.510 99.571 
8000 99.535 99.593 
10000 99.560 99.615 
12500 99.588 99.640 
16000 99.615 99.663 EN 10   EN 20000 99.639 99.684 
25000 99.657 99.700 
31500 99.671 99.712 
40000 99.684 99.724 
Minimum PEI values for kVA ratings that fall in  between the ratings given in Table I.4 shall 
be calculated by linear interpolation 
Table I.5: Minimum Peak Efficiency Index (PEI) values for dry type  medium power 
transformers 
Tier 1 (01.07.2015) Tier 2 (01.07.2021) RATED POWER 
(kVA)  Minimum Peak Efficiency Index (%) 
4000 99.348 99.382 
5000 99.354 99.387 
6300 99.356 99.389 
8000 99.357 99.390 
10000 99.357 99.390 
Minimum PEI values for kVA ratings that fall in  between the ratings given in Table I.5 shall 
be calculated by linear interpolation 
1.3) Requirements for medium power transformers with rated power ≤ 3150kVA 
equipped with tapping connections suitable for operation while being energised or on-
load for voltage adaptation purposes. Voltage  Regulation Distribution Transformers are 
included in this category. 
The maximum allowable levels of losses set out in  Tables I.1 and I.2 of this Annex I can be 
increased by 20% for no load lo sses and 5% for load losses in  Tier 1 and by 10% for no load 
losses in Tier 2.  
1.4) Requirements for medium pow er pole-mounted transformers  
The levels of load and no load losses indicated in Tables I.1 and I.2 are not applicable to pole-
mounted transformers with power ratings be tween 25 kVA and 160 kVA. For these specific 
models of medium power pole- mounted transformers, the ma ximum levels of allowable 
losses are set out in Table I.6.  
Table I.6 Maximum load and no-load losses fo r medium power pole-mounted transformers 
 Tier 1 (1.07.2015) Tier 2 (1.07.2021) EN 11   EN Um 
(kVA) 
 Maximum load 
losses (in Watts) * Maximum no-
load losses (in Watts)* Maximum load 
losses (in Watts)* Maximum no-load 
losses (in Watts)* 
25 Ck (900) Ao (70) Bk (725) Ao (70) 
50 Ck (1100) Ao (90) Bk (875) Ao (90) 
100 Ck (1750) Ao (145) Bk (1250) Ao (145) 
160 Ck+32% (3102) Co (300) Ck+32% (3102) Co-10% (270) 
*Maximum allowable losses for kVA ratings that fall in between the ratings given in Table I.6 
shall be obtained by linear interpolation 
2) Minimum energy efficiency requirements for large power transformers 
The minimum efficiency requirements for large power transformers are set out in Table I.7 
Table I.7 Minimum Peak Efficiency Index requirements for large power transformers 
Tier 1 (01.07.2015) Tier 2 (01.07.2021) 
RATED POWER (MVA)  
Minimum Peak Efficiency Index (%) 
≤ 4 99.465 99.532 
5 99.483 99.548 
6.3 99.510 99.571 
8 99.535 99.593 
10 99.560 99.615 
12.5 99.588 99.640 
16 99.615 99.663 
20 99.639 99.684 
25 99.657 99.700 
31.5 99.671 99.712 
40 99.684 99.724 
50 99.696 99.734 
63 99.709 99.745 
80 99.723 99.758 EN 12   EN ≥100 99.737 99.770 EN 13   EN  
3) Product information requirements 
From 1 July 2015, the following product in formation requirements shall apply: 
Information on rated power, load loss and no-load  loss and the electrical  power of any cooling 
system required at no load shal l be included in any related pr oduct documentation, as well as 
on the transformer’s rating plate. 
For medium power (where applicable) and larg e power transformers, the value of the Peak 
Efficiency Index and the power at which it  occurs shall be included in the product 
documentation and marked on the rating plate. 
Information on the weight of all the main components of a transf ormer (including the 
conductor, the nature of the conductor and the co re material) shall be included in any related 
product documentation. 
Pole mounted distribution transformers shall ha ve their application mentioned in any related 
product documentation and shall include the ISO caution mark to read their documentation.  EN 14   EN Annex II  
Measurement and calculation methods 
Measurement method 
For the purpose of compliance with the require ments of this Regulati on, measurements shall 
be made using a reliable, accurate and reproducible measurement procedure, which takes into account the generally recognised state of the art measurement methods, including methods set 
out in documents the reference numbers of which have been published for that purpose in the 
Official Journal of the European Union. 
Calculation methods 
The methodology for calculating the Peak Efficien cy Index (PEI) for medium and large power 
transformers is based on the ratio of the transmitted apparent power of a transformer minus the electrical losses to the transmitted apparent power of the transformer.  
 
Where: 
P0 is the no load losses measure at rated vo ltage and rated frequency, on the rated tap 
Pc0 is the electrical power required by the cooling system for no load operation 
Pk is the measured losses at rated current and rated frequency on the rated tap corrected to 
reference temperature according to EN 60076-2 
Sr is the rated power of the transf ormer or autotransformer on which P k is based EN 15   EN Annex III  
Verification procedure 
For the purposes of checking compliance with  the requirements laid down in Annex I, 
Member States authorities shall use the measur ement methods and calculation methods set out 
in Annex II.  
Given the weight and size limitations in th e transportation of medium and large power 
transformers, Member States authorities may d ecide to undertake the verification procedure at 
the premises of manufacturers, before they are put into service in their final destination.  
The model shall be considered to comply with the energy performance or efficiency 
provisions set out in this  Regulation, if the measured parame ters meet the requirements set out 
in Annex I within the verification tolerances  indicated in Table 1 of this Annex. The 
verification tolerances set out in this Annex re late only to the verifi cation of the measured 
parameters by Member States authorities and shall not be used by the manufacturer or 
importer as an allowed tolerance to establish the values in the tec hnical documentation.  
  
Table 1.  
Measured parameter Verification tolerances 
Load losses The measured value shall not be greater than 
the declared value by more than 5 %.  
No load losses The measured value shall not be greater than 
the declared value by more than 5 %.