
Free
About
The classroom edition of XFMR Lab, for utilities and lineman training programs.
Wire it. Energize it. Find out what went wrong before you do it on a pole. XFMR Lab simulates utility distribution transformer banks with the meters, fuses and fault behavior you would see on the real thing. Built by a working journeyman lineman for apprentices and crews who would rather make their mistakes in an app than in the field.
This edition is for organizations. Licensed Code Access Only: your school or employer gives you a code, and the app opens. There is nothing to buy inside the app. Individuals can find the public edition on the App Store as Lineman's Reference - XFMR Lab.
FOR INSTRUCTORS:
The Instructor Board runs creates a class you run from an iPad or phone. Start a session, give students the join code, and assign labs to the whole class, a group or one student. As they work you see each student's wiring live on your screen, along with failed checks, blown fuses, hazards and their score. Students can raise a hand, skip a lab for a second look, or say I don't know; you can mark a lab assisted when you walked them through it. Homework sessions stay open for days with a due time. At the end, the results are on your board and export cleanly as a CSV you can download or email.
FOR STUDENTS
Join a session with a code and a nickname. Your instructor sees your progress while a lab is open, and the card on your screen says exactly what they can and cannot see. Outside a session, every lab and reference below is yours to practice on.
THE LABS
Single Phase: Single Bushing Topside, Dual Bushing Topside.
Three Phase, closed banks: Delta-Delta, Delta-Wye, Wye-Delta, Wye-Wye.
Three Phase, open banks: Open Delta-Delta, Open Wye-Delta.
Misc: Paralleling, 4th Cutout, Death Traps.
Advanced: Straight 480, 240/480, 277/480, Corner-Grounded 240/480, Wye-Wye 5-Wire (120/240 plus 120/208).
Sandbox Lab (Beta): free-form wiring with a live phasor solver.
TOOLS AND REFERENCE
Volt, ohm and rotation meters with real fault behavior. Nameplate and secondary coil inspection. Reference Diagrams, Basics and the Advanced Transformer Reference. A rebuilt Tutorial of 8 hands-on chapters, and the Training track of lessons.
Classic Quiz grades all 14 quiz-eligible labs: blowing fuses and failing Check Work subtract from your score. Advanced Quiz gives you job-site information, has you pick the nameplate and coil configuration, then wire it. Learning Mode walks apprentices through every wrong-connection check one at a time; journeymen turn it off for the test.
Class sessions send a student's nickname, results and live wiring to the instructor's board and erase them from our servers when the class ends. Nothing is used for tracking or advertising.
Built for linemen, by a lineman.
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What's New in XFMR Lab Enterprise
1.0
October 8, 2026







