Hirst Magnetic Instruments Ltd.: Manufacturer of magnetising, demagnetising, magnet calibration and magnet processing and magnetic measurements equipment.
Northern Technology and Testing: Offers independent testing of dissolved gases, DGA, PCE, PCB, furan, metals and transformer fluid analysis for the electrical power industry, from Sacramento, California.
TJ/H2b Analytical Services, Inc.: Offers analysis and consulting in diagnostic testing of oil, gas and insulating materials used in high-voltage electrical equipment. International contacts from their base in Sacramento, California.
Vasavi Electronics: Fabricates automatic test equipment for transformers, coils , relays and cables.