Megger Group Limited
Megger
Megger Group Limited is a British designer and manufacturer of electrical test, measurement and monitoring equipment for the power industry, and one of the most recognisable names in high-voltage diagnostics. It is headquartered at Archcliffe Road in Dover, Kent, where the head office shares a site with a major manufacturing and engineering operation, and sells worldwide under brands including Megger, AVO, Biddle, States, Programma, SebaKMT and Power Diagnostix.
The Megger name is the company's oldest asset. Sydney Evershed's hand-driven dynamo generated voltages high enough to measure resistance in the megohm range, and the resulting insulation tester, the “Megger”, was registered as a trademark in 1903. The word became the standard term for insulation resistance testing — unusually strong brand equity for an instrument maker — and the lineage reaches back to 1889 through Evershed & Vignoles, the AVO Meter (the world's first multimeter, 1923) and the James G. Biddle Company in the United States.
The portfolio spans the full maintenance lifecycle of electrical assets. Offline testing covers insulation resistance testers from handheld units to 5 kV and above, low-resistance ohmmeters, earth resistance instruments and multifunction installation testers. Heavier equipment includes transformer test systems, dielectric and sweep frequency response analysers, circuit-breaker analysers, relay protection test sets, motor and generator testers, high-voltage switchgear diagnostics, VLF withstand sets and mobile cable fault location vans. Online monitoring adds partial-discharge measurement, grid sensors, dynamic line rating and cloud analytics.
Manufacturing is largely in-house. ESCO Technologies counted seven manufacturing facilities in its April 2026 acquisition disclosure, concentrated in Dover in the United Kingdom, Dallas and Valley Forge in the United States, Danderyd in Sweden and Germany, where SebaKMT has its cable fault location base. Dover runs its own EMC laboratory and surface-mount assembly lines, and calibration is traceable to NIST, the UK National Physical Laboratory and ISO/IEC 17025 accredited laboratories. The group employs over 1,950 people; Europe accounts for about 35% of sales, North America 30%, Asia 15% and the rest of the world 20%.
Ownership has changed rarely. After a management buyout in 1987 the business traded as Megger Instruments, and in 1991 it was acquired by TBG AG, the Swiss Thyssen-Bornemisza group, which merged Megger with Biddle and Multi-Amp in 1995 to form AVO International. Megger Group Limited has been the registered UK entity since 6 June 2002 and remains unlisted. In April 2026 ESCO Technologies agreed to acquire the company from TBG for US$2.35 billion, with completion expected by the first quarter of its fiscal 2027. Its distinctive quality is a combination of generic-name heritage, broad coverage of the high-voltage test workflow and manufacturing that remains in-house.
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Megger Group Limited is a British designer and manufacturer of electrical test, measurement and monitoring equipment for the power industry, and one of the most recognisable names in high-voltage diagnostics. It is headquartered at Archcliffe Road in Dover, Kent, where the head office shares a site with a major manufacturing and engineering operation, and sells worldwide under brands including Megger, AVO, Biddle, States, Programma, SebaKMT and Power Diagnostix.
The Megger name is the company's oldest asset. Sydney Evershed's hand-driven dynamo generated voltages high enough to measure resistance in the megohm range, and the resulting insulation tester, the “Megger”, was registered as a trademark in 1903. The word became the standard term for insulation resistance testing — unusually strong brand equity for an instrument maker — and the lineage reaches back to 1889 through Evershed & Vignoles, the AVO Meter (the world's first multimeter, 1923) and the James G. Biddle Company in the United States.
The portfolio spans the full maintenance lifecycle of electrical assets. Offline testing covers insulation resistance testers from handheld units to 5 kV and above, low-resistance ohmmeters, earth resistance instruments and multifunction installation testers. Heavier equipment includes transformer test systems, dielectric and sweep frequency response analysers, circuit-breaker analysers, relay protection test sets, motor and generator testers, high-voltage switchgear diagnostics, VLF withstand sets and mobile cable fault location vans. Online monitoring adds partial-discharge measurement, grid sensors, dynamic line rating and cloud analytics.
Manufacturing is largely in-house. ESCO Technologies counted seven manufacturing facilities in its April 2026 acquisition disclosure, concentrated in Dover in the United Kingdom, Dallas and Valley Forge in the United States, Danderyd in Sweden and Germany, where SebaKMT has its cable fault location base. Dover runs its own EMC laboratory and surface-mount assembly lines, and calibration is traceable to NIST, the UK National Physical Laboratory and ISO/IEC 17025 accredited laboratories. The group employs over 1,950 people; Europe accounts for about 35% of sales, North America 30%, Asia 15% and the rest of the world 20%.
Ownership has changed rarely. After a management buyout in 1987 the business traded as Megger Instruments, and in 1991 it was acquired by TBG AG, the Swiss Thyssen-Bornemisza group, which merged Megger with Biddle and Multi-Amp in 1995 to form AVO International. Megger Group Limited has been the registered UK entity since 6 June 2002 and remains unlisted. In April 2026 ESCO Technologies agreed to acquire the company from TBG for US$2.35 billion, with completion expected by the first quarter of its fiscal 2027. Its distinctive quality is a combination of generic-name heritage, broad coverage of the high-voltage test workflow and manufacturing that remains in-house.
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Quick Facts
Headquarters
Dover, Kent, United Kingdom
Founded
1889
Employees
~1,950
Revenue
Approximately US$590 million (FY2026 projected revenue, disclosed by ESCO Technologies in its April 2026 acquisition announcement; Megger's own UK accounts for the year ended 30 November 2025 are filed at Companies House)
Factories
Megger manufactures in owned plants concentrated in Dover in the United Kingdom, Dallas and Valley Forge in the United States, Danderyd in Sweden and Germany, where the SebaKMT cable fault location business has its production base, giving seven manufacturing facilities in total according to ESCO Technologies' April 2026 acquisition disclosure.
Listing
Unlisted
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This corporate profile is compiled from publicly available sources including company annual reports, SEC/regulatory filings, official press releases, and verified third-party industry databases. Financial figures reflect the most recent fiscal year disclosures and are cross-validated across multiple independent references.
VerityRank Score is calculated using a proprietary multi-dimensional model evaluating market presence, financial strength, operational scale, innovation capacity, and brand influence. Individual dimension scores are normalized against industry peers and updated quarterly.
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Key references: Official Website , Megger – About Us · Megger – History · ESCO Technologies – Megger acquisition · Drives & Controls · UK Companies House