Pad mounted transformer manufacturers

172 companies hold a UL listing to build liquid-filled pad-mounted transformers for the US market, across 24 countries. 39 of them are US manufacturers and 71 are in China. 73 of the 172, about 42 percent, are TAA eligible.

Padmount Supply, 24 September 2026. Free to cite with a link.

The companies we track, and what each one actually is

Every company below holds or has held a listing to build or sell liquid-filled pad-mounted units into the US market. The UL file number is the column worth reading first. It is the cleanest public filter there is for separating a real manufacturer from a trading company, and almost nobody publishes these in one place.

UL file numbers are given as published under category XPLH. Where a company shows “Not published” we could not find a file in that category, which is not the same as saying one does not exist. TAA eligibility follows FAR 25.003, FAR 25.003, US made end products plus designated country end products.

Manufacturer, supplier, distributor, the words are not interchangeable

Most buying mistakes on these units start with this confusion, so it is worth being blunt about it.

A manufacturer builds to order. You are buying a slot in their production queue, so the lead time is however long that queue happens to be. At the moment that is routinely measured in months, not weeks. The price is usually the lowest you will see and the wait is usually the longest.

A stocking distributor holds finished units on the floor. You are buying something that already exists, so the only lead time is freight. You pay more per unit and you get it this month. When a job is already behind schedule, which is when most people start calling, this is the only option that is actually available.

A global OEM builds at volume, mostly for utilities on framework contracts. They rarely quote a single distribution rating to a new account and normally push you to a rep firm. Their names carry weight on a submittal, which is sometimes the whole reason to specify them.

The word “factory” in a search result tells you almost nothing, because overseas trading companies use it freely. The UL file number in the table above is a far better test than the word on the website.

Where the 172 listed manufacturers actually are

The supply base is far more international than the US market generally assumes. China alone accounts for 41 percent of listed companies, more than the United States, and none of those are TAA eligible.

The full 24 country breakdown, free to cite

Why the practical list is much shorter than 172

A UL listing says a company is permitted to build these. It does not say they will sell you one. Global OEMs rarely quote a distributor for a single 150 kVA unit. US factories route new accounts through rep firms, which adds a month before you have a number. Overseas factories frequently carry a minimum order of a full container, which is four units at 1000 kVA and two above 1500 kVA, so a single unit is not a conversation they will have.

Once you remove everyone who will not quote a new account, will not sell a single unit, or cannot meet DOE 2016 efficiency under 10 CFR Part 431, the list of companies you can realistically buy from this quarter is a small fraction of the 172. That is the gap this page exists to close.

Two dates worth knowing before you choose a source

The Section 232 transitional rate on grid equipment, 15 percent rather than 50, expires on 31 December 2027. That window is the reason imported supply currently prices the way it does, and it is finite.

DOE 2016 efficiency under 10 CFR Part 431 stays mandatory until April 2029, so stock bought today remains compliant for the life of most projects. Units above 2500 kVA sit outside that rule entirely, which is a feature on some jobs and a disclosure on all of them.

Every company, in detail

Common questions