Manufacturer profile
About Vanguard Instruments
Reviewed 2026-07-26
Vanguard Instruments Company, Inc. develops diagnostic test equipment for electric-power apparatus, especially transformers, circuit breakers, and protective relays. Its manual-relevant products include circuit-breaker analyzers, micro-ohmmeters, transformer turns-ratio and winding-resistance instruments, and primary-current-injection systems used in utility maintenance and commissioning.
History
An official Vanguard product datasheet states that the company was founded in 1991 and initially developed a computerized extra-high-voltage circuit-breaker analyzer. It says the product line subsequently expanded into micro-ohmmeters, transformer turns-ratio testers, winding-resistance meters, and other diagnostic instruments for transformers, circuit breakers, and protective relays. That account supports a 1991 founding date and an electrical-utility test-equipment identity, rather than the unrelated investment-management or publishing organizations that can appear in broad searches for Vanguard.
Doble Engineering's official acquisition history records that it acquired Vanguard Instruments in 2017 and describes Vanguard as a provider of test equipment whose extra-high-voltage circuit-breaker analyzers expanded Doble's circuit-breaker offerings. Current Vanguard-hosted product pages continue to document circuit-breaker analyzers, contact-resistance micro-ohmmeters, and primary-current-injection equipment. Because the reviewed headquarters evidence comes from older product literature and current legal integration is not fully stated on the pages reviewed, this draft deliberately omits a current headquarters and current ownership field.
Equipment specialties
- circuit-breaker analyzers and timers
- micro-ohmmeters and contact-resistance meters
- transformer turns-ratio and winding-resistance testers
- protective-relay and primary-current-injection test equipment
- electrical utility diagnostic instruments
Sources
- CT-3500 S2 Digital Circuit Breaker Analyzer Datasheet — Vanguard Instruments Company, Inc. (accessed 2026-07-26)
- 100 Years of Doble: How Our Acquisitions Shaped the Industry — Doble Engineering Company (accessed 2026-07-26)
- CT-8000 S3 Circuit Breaker Analyzer — Vanguard Instruments (accessed 2026-07-26)
- DMOM-200 S3 Micro-Ohmmeter — Vanguard Instruments (accessed 2026-07-26)
- PCI-600 Primary Current Injection Test Set — Vanguard Instruments (accessed 2026-07-26)