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Updated catalogs and guide specs

Rex Power Magnetics has posted an updated catalog for General Purpose Distribution transformers. The catalog features updated electrical and dimensional information for isolation transformers, autotransformers, K-Rated and drive Isolation transformers, encapsulated transformers, and sealed (non-ventilated) transformers.

The new catalogs are complimented by new Product Guide Specifications, which can be a handy reference for specifying engineers, as well as for general reference.
These downloads are available online, in the downloads section, at

For your convenience, the following links are also available


Dry Type Distribution Transformer [English]
Dry Type Distribution Transformer [French]

Product Guide Specifications

Distribution Isolation Transformers (≤1,000 kVA, ≤1.2kV Class)
Autotransformers (≤1,000 kVA, ≤1.2kV Class)
Encapsulated Transformers (≤150 kVA, ≤0.6 kV Class)
Mini Power Centers
RC Snubbers

Upcoming Changes to enclosure sizes

Important Upcoming Changes to standard enclosure sizes

Rex Power Magnetics is announcing a significant design change to its standard enclosures.

This change will affect all ventilated transformers 15 kVA and up.

The reason for the change stems from DOE 2016 and NRCAN 2019 efficiency changes; Rex’s designs have been improved and optimized to reduce the amount of valuable floorspace required for most commonly ordered ratings.

The new designs for each enclosure size have the same width and depth as the outgoing design, but the transformer height is increased (3” to 12” depending on the enclosure). Floor mounting dimensions are not affected. The new taller enclosures will permit many kVA ratings to drop down one size, meaning a smaller package overall versus prior to the change. Additionally, each kVA rating will have one corresponding enclosure, regardless of conductor type or temperature-rise level.

The switch-over date for the new enclosure size will be April 1st, 2019, meaning transformers shipping on that day or later may utilize the new sizes.

Rex will accomodate any requests for the old style to be retained when requested or specified by means of approval drawing process. Details and dates for the transition are below.

This bulletin contains a table that compares the old sizes with the new.

Milestone Dates

As of March 4th, 2019, Rex will circulate this bulletin to advise customers of the upcoming change. For new orders shipping beyond April 1st, customers should be aware that the new sizes will be used. For customers who are sensitive to the enclosure dimensions, requiring the old enclosure sizes to be retained, Rex’s Sales must be notified with sufficient advance notice prior to scheduled shipment. This can be done in two ways:

  1. Express written communication to our inside sales, who will note the requirement in the part number.
  2. Approval drawing process. As always, the approval drawing process assures compliance to drawing.

If you already have an order in our system, scheduled for shipment after April 1st, that may be affected by this dimension change, Rex may produce your transformer with the old enclosure size, or the new one. For customers who wish to specify the enclosure size, Rex’s Sales must be notified as with new orders.

The Rex Power Magnetics website makes available drawings for convenient reference to many of the most commonly ordered transformers. All of the drawings affected by this change will be updated over the course of the month, and it is anticipated that the transition will be complete before April 1st.


Dry Type Transformer Minimum Efficiency Rules (Canada)


  • Natural Resources Canada (NRCan) has announced that it will adopt a new set of minimum efficiency standards for Dry-Type Transformers that are sold in Canada.
  • This will have a significant impact for distributors and end users in all Canadian provinces besides Ontario; In Ontario, the Ministry of Energy had already adopted the higher efficiency levels as of 2018. Across the country, the new rule takes effect on May 1st, 2019.
  • The rule replaces the current minimum efficiency level, known as CSA C802.2-12. The new efficiency level will likely be commonly reffered to as NRCan 2019.
  • With this change, the Canadian (NRCan 2019) and US (DOE 2016) standards will be largely harmonized. Minor differences exist; Rex has another document available that offers an in-depth analysis.
  • With NRCan 2019, the increase in the required minimum efficiency level is significant, leading to downstream savings in electrical costs for the owner. The transformer’s energy losses are reduced by 29%-36%, depending on the kVA, which also translates into a positive environmental impact. The impact on up-front cost is also significant: up to 30% more expensive, depending on the kVA, and other selected features.

The official government notification of the upcoming change is published here:

Rex has been designing and producing CSA and UL approved transformers at the NRCan 2019 efficiency level, and higher, for over 5 years.


Compliant transformers are labelled under the “Green Line” Trademark

Changes for Transformer Markings & Dimensions

  • As part of the transition to NRCan 2019 efficiency levels, Rex will begin a transition in our standard enclosure designs. New standard enclsorue will be taller, but there will be no change to width or depth. Details will be provided soon.
  • As always, ethe efficiency level is indicated in the part numbering. NRVan 2019 transforemr will have part numbers ending with the suffix “/Z3” versus “/Z” for C802.2-12.

Upcoming Milestone Dates

  • The last date on which Rex Power Magnetics may manufacture a transformer for Canada at the old C802.2-12 level is April 30th, 2019.
  • For Low Voltage (Distribution) Transformers that are to be built to the outgoing C802.2-12 standard, Rex recommends release to manufacture by March 1st, 2019.
  • For new orders in March, Rex may be able to accept non NRCan 2019 transforemrs on a rush basis, depending on factory loading. Rex cannot store any transfomers for later delivery.
  • For Medium Voltage (Power Transformers) that are to be built to the outgoing C802.2-12 standard, Rex requires release to manufacture by February 8th 2019, with a scheduled ship date prior to May 1st.



New higher efficiency levels for certain transformers became effective in the US market as of January 2016 (U.S. DOE 2016).

Similar requirements came into effect in Ontario (Canada) beginning January 2018. Other Canadian provinces are to implement the same changes as Ontario starting May 1, 2019.

It is the customer’s responsibility to ensure the transformers meet the mandated efficiency level in the intended jurisdiction of installation.

More details availble from Natural Resources 


As you are aware Natural Resources Canada (NRCan) started a process to adopt higher efficiency levels for dry Type Transformers that are harmonized with DOE2016 (USA Department of Energy) efficiency levels currently in effect in the USA. These NRCan regulations were originally intended to come into effect January 1 2018. However, this has since been delayed and the earliest possible effective date for The NRCan higher efficiency regulation in Canada is now early 2019.

Due to the jurisdictional separation of federal and provincial governments in Canada, federal and provincial legislation for energy efficiency must be complementary for it to be meaningful. For minimum energy efficiency requirements for dry type transformers the NRCan legislation establishes the requirements for importation into Canada and movement of goods within provincial borders and individual provincial legislation establishes the same requirements within each province.

In anticipation of the NRCan legislation originally intended for January 1 2018, The Ontario Ministry of Energy established legislation to also become effective as of January 1 2018 for Ontario. However, to our knowledge no other province in Canada has established legislation in this regard to date.

This unintentional difference in effective dates of this legislation cannot be readily corrected by Federal or Ontario Provincial legislatures as rescinding or expediting legislation is neither possible nor practical.

We have consulted with the Ontario Ministry of Energy and they have stated that “…there are no enforcement provisions…However, we (the Ministry) expect manufacturers and dealers selling in Ontario to comply with the regulation….manufacturers include all manufacturers selling in Ontario (not only Ontario based manufacturers).”

Rex Power Magnetics supports the shift to these more stringent efficiency requirements and is fully prepared to offer product and pricing that comply with current and future higher efficiency levels. Product intended for Ontario will be quoted to meet Ontario efficiency regulations. Product intended for all other provinces or those that are exempt from these regulations will continue being priced to meet the current NRCan energy efficiency requirements

We regret the confusion that this lack of legislative clarity has created in the Ontario market. Please do not hesitate to contact us for any questions you may have.

Rex Power Magnetics