About Tierney Electrical

Since 1938, Tierney Electrical Manufacturing Company has built a solid reputation as a dependable source of all copper wound, conservatively designed dry-type transformers.


Customer satisfaction is a top priority for Tierney. We look forward to forming relationships with new customers, as well as continuing to serve our current customers. Our reputation is built upon customer satisfaction, a quality product, and speedy, reliable delivery. Our energy efficient copper wound transformer's service life outlasts the mass produced aluminum wound transformer - two to three times longer.

Photo About Tierney

The success of the company over the past 78+ years can be attributed to basically four things:

  • Our continued high quality and extremely dependable copper wound products.
  • Our good customer relationships that we have developed over the years.
  • Our dedicated employees with many years of experience in the manufacture of dry-type air-cooled electrical transformers.
  • Our quick and reliable delivery.

All Tierney Products are Manufactured in the United States.

With our manufacturing plant and business offices located in Seattle, Washington, Tierney Electrical Manufacturing Company offers very efficient operating air-cooled transformers, sized 50 VA through 3000 KVA.


Environmentally Compliant


Tierney Transformers labeled "TP" currently meet the Department of Energy 2016 Energy Conservation Standards and Requirements.


Through DOE analysis these new stringent 2016 standards help to provide the maximum improvement in customers Energy Savings and Operating costs, as well as delivering significant environmental benefits by reducing emissions.

By meeting these standards Tierney transformers provide the most efficient and reliable product for our customers and our environment.

Statement of Policy

It is the firm belief and policy of Tierney Electrical Mfg. Company that all transformers must meet all requirements of a customers specification 100%. We do not believe that any single manufacturer's standard product, however good it may be, can possibly provide an ideal solution to all transformer applications. Variations in voltage ratios, KVA ratings, size limitations, taps, frequency, etc., provide many application problems which can be solved only by custom-design and manufacture.


To maintain our policy of 100% fulfillment of specifications, we will, when necessary, alter our standard designs and make the required revisions to our normal manufacturing processes to ensure that the user obtains a high-quality transformer exactly meeting specifications.


Our standard transformers are designed to operate 3 to 5 dB below ANSI standards which result in a very quiet operating transformer.


For those applications requiring a transformer having a sound level much lower than ANSI standards, we will design and construct a transformer guaranteed to meet the specified sound levels. These units are individually sound-level tested using ANSI Standard test procedures, and copies of certified test reports are furnished to the specifying authority as proof of compliance.