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TSTM manufactures and provides meter sockets and voltage transformers to the electrical industry nationwide.

Today building the most accurate voltage transformers in the industry, TSTM is a fully independent company that sprang from the experience and resources of a meter services operation known as May Engineering. Begun over 60 years ago in Albert Lea, Minnesota, May Engineering pioneered the Mobile Meter Shop with a fleet of trucks able to bring much-needed services across the Upper Midwest.

TSTM President and CEO Greg May grew up in the industry, moved May Engineering to South Dakota in 1984, and began TSTM in 1996 to explore the marketability of products developed in response to a catastrophic solid-state meter explosion in Nebraska. With a number of transformer and transformer-related patents to his credit, Greg is acknowledged among the top metering experts in the nation.

TSTM’s VT Pack voltage transformer assembly has revolutionized metering safety, accuracy, and robustness. This lightweight, easily-installed multi-transformer assemblage is today’s product of choice among discriminating players, meeting the most rigid manufacturing and durability standards.