Megger Group Limited

Megger Group Limited
Megger Group Limited
Type Private
Industry Electrical power
Founded 1889
Founder(s) Sydney Evershed and Ernest Vignoles
Headquarters Dover (UK); Dallas, Texas; Valley Forge, Pennsylvania (USA), Täby (Sweden)
Products Electrical test and measurement equipment
Revenue $19.2m [1]
Employees 1500

Megger Group Limited is a company that manufactures electric test equipment and measuring instruments for electrical power applications.

The company is known for their original electrical insulation testers, and supply products related to the following areas: cable fault locating, earth/ground testing, low resistance measuring, power quality, electrical wiring, insulation testers, multimeters, portable appliance testers, clamp-on meters, current transformers, etc.

The company logo depicts the word Megger with red capital "M" and the remaining letters in black, all on white background.



Over the years there were several companies whose names were associated or assimilated into Megger.

Evershed & Vignoles

Wee Megger insulation tester
Modern version of Megger insulation tester MIT520/2

Sydney Evershed (1858–1939) and Ernest Vignoles bought the instrument section of Goolden and Trotter (where they both worked) and founded Evershed & Vignoles Limited on 5 February 1895. [2] However, it is likely that the origins of Megger can be traced back to 1889. [3] The company was based at Acton Lane Works, Chiswick, London, England where it moved from Westbourne Park in 1903.

Sydney Evershed applied for several patents for various electric devices. [4] [5]

One of them was a "hand dynamo", [6] which allowed generation of voltages high enough to measure resistance in the megohm range and thus construction of a first portable insulation tester. The MEGaohm metER was then named as Megger and the word became a trademark name registered on 25 May 1903. [7] The invention became a popular method of insulation testing and by 1920s it was "well-known" by other engineers. [8] [9]

Due to electromagnetic interference the first Megger insulation testers were built as two separate boxes – one for voltage generation and one for measurement. They were later integrated into a single device in a Bakelite case and special foldable handle for driving the dynamo. The most popular was the so-called "Wee Megger" (voltage up to 500 V and resistance up to 20 megohms), but there were larger devices like the "Major Megger", "Meg" or "Megger insulation tester", which could generate up to 2500 V and measure resistance up to 20,000 megohms. [10] [11] (Modern version of Megger - model MJ15 - can generate up to 5 kV.[12])

In the 1920s the company employed approximately 500 people. The number rose to 1000 during the Second World War to reach its peak of 1870 in 1967. [13]

In 1965 Evershed & Vignoles Ltd. Became a part of the George Kent Group. [14]

H.W. Sullivan Ltd

The company (established in 1922) was producing precision laboratory equipment (e.g. resistors, inductors, shunts, galvanometers, etc.[15]). H.W. Sullivan Ltd was incorporated into Megger in 2002.[16]


AVOmeter model 8 Mk7

The invention of the first multimeter is attributed to a Post Office engineer Donald Macadie, [17] who became dissatisfied with having to carry many separate instruments required for the maintenance of the telecommunication circuits. Macadie invented a first instrument, which could measure Amps, Volts and Ohms, so the multifunctional meter was then named as AVO. [18]

Macadie took his idea to the Automatic Coil Winder and Electrical Equipment Company (ACWEECO, founded probably in 1923).[18] The first AVO was put on sale in 1923, and although it was initially a DC-only instrument many of its features remained almost unaltered right through to the last Model 8.

ACWEECO later became known as AVO Limited and manufactured instruments with the AVO trademark.[19]

The original AVO multimeter was manufactured continuously since its first appearance in 1923. The final model was made in October 2008, when its production was terminated only due to increasing problems with obtaining the spare mechanical parts. The final AVO Model 8 introduced in 1951 became an electronic device present in the market for 57 years without major modifications.[20][21]

AVO Training Institute

In 1963 Multi-Amp and AVO created Multi-Amp Institute. In 2004 the Institute became AVO Training Institute, Inc. with the headquarters in Dallas, Texas. AVO Training Institute was established for providing training in electrical engineering, particularly regarding safety, maintenance and testing of electrical equipment, also by using instruments from competitive manufacturers.

In 1996 the Institute was certified with ISO 9001 and so far over 230,000 electrical maintenance and testing technicians and engineers from around the world have attended training courses.[22]

The Institute has a Technical Resource Center - an online store offering books, standards, training materials, Personal Protective Equipment, and tools. [23] The actual training can be organised in different sites around the world, for example at the Megger facility in Paris. [24]

The AVO Electrical Engineering Division was created in 2002 and it specialises in power system studies, specifically arc flash hazard analysis.[25]

Thorn Electronics/EMI

In 1970, along with other members of the George Kent Group the company was acquired by Thorn Electrical Industries founded in 1936. [26] The company was taken over by Thorn EMI in 1967 (linked with company EMI), which at the same time also bought AVO Limited.

In 1987 the name of the company was for the first time changed to Megger Instruments Limited. [27]

Present times


Megger Instruments Limited was based at AVO’s Dover site, in Archcliffe Road, Dover, CT17 9EN, Kent, England, which is also the present location of the UK branch of the company.

In 1991, due to the popularity of the AVO products the company changed the name to AVO Megger Instruments Limited. In 2000 the company became known as AVO International Holdings Limited and in 2002 as AVO International Limited.

Finally the whole Megger group changed its name to Megger Group Limited in 2002, as it is known today.

The Dover site employs around 230 people. [28] In total (including the sales channels) Megger Group Limited employs around 1500 people worldwide.

In recognition of the ground breaking inventions, which made it possible to build the Megger group the main meeting rooms at the Dover site are named after Evershed and Macadie.


For many years, the James G. Biddle Company in Pennsylvania, was the USA importer of Megger products, as well as a manufacturer of equipment under their own name. In 1989, using concepts introduced by Commonwealth Edison Company of Chicago, Biddle started development of a range of equipment to test the integrity of large battery systems, which led to the BITE (Battery Impedance Test Equipment) line of products.

In 1991 Biddle, Megger and MultiAmp joined together to form AVO International. The use of the Biddle trademark was retained for many of products still available today. Biddle was one of the first companies to provide commercial cable fault locators. [29]


Megger Group Ltd. owns the US site in Dallas, Texas. They manufacture terminal blocks and test switches under the trademark States (existing since 1940s). [30]


PowerDB was acquired in autumn 2005. They provide "acceptance and maintenance test data management software" which is compatible with many Megger products. [31]


Programma Electric AB is a Swedish electrical test and measurement equipment manufacturer and was founded in 1976. [32] It provided products including: circuit breaker analysers, battery load testers, primary injection testers, vacuum interrupter testers, microhmmeters and protective relay test instruments. The production plant facility is located in Täby, Sweden.

In March 2001 Programma was sold to GE Energy and joined Megger Group Ltd. in June 2007. [33] [34]

Pax Diagnostics

In October 2008 Megger Group Ltd. acquired Pax Diagnostics in Sweden. Pax manufactures transformer testing and insulation diagnostics equipment. Pax Diagnostics was founded in 2004 by former employees of Programma Electric, and it is also based in Täby. [35]

Intellectual property


The first trademark of the company, the name Megger was registered in 1903 and it remains the intellectual property of the Megger Ltd.

It is incorrect to use the word "Megger" as a verb, noun or in the plural form. [36] It is an infringement of the trademark if used in reference to a product not made by the Megger Group or its subsidiaries.[37][38], see genericized trademark.

Most of the names and trademarks of the acquired companies are now owned by Megger Group Ltd. Apart from "Megger" itself, the best known ones are: AVO, Biddle, Biddle AVO, Biddle Megger, States, PowerDB, and recently Programma and Pax Diagnostics.

However, some of the names of the products are also protected: Megger, AVO, DLRO, MFT, MIT, MPRT, etc.

The Group publishes a copyrighted but distributed for free quarterly magazine titled "Electrical tester" aimed at electrical engineers who might use products from the Megger range.[39]


It is difficult to assess the actual number of patents, because some of them were obtained before acquired companies joined Megger Group. The original Megger insulation tester patent is over 100 years old.

Centenary certificate of Megger trademark

On 25 May 2003 Megger Group celebrated a century of innovation. [40]

The table shows a timeline of some typical devices introduced by Megger Group companies (not necessarily covered with patents). In recent years the company has also paid more attention to the ergonomics and design of their products. [41]

Year Device
1889 Portable insulation tester (Megger)
1908 Low resistance Ohmmeter (LRO)
1923 Multimeter with Amps, Volts and Ohms (AVO)
1928 Multistation watt-hour meter test board
1942 Resistive load box
1950 Cable fault locator
1951 Protective relay test set
1953 Partial discharge (Corona) detection system
1968 Portable digital multimeter
1979 Digital line earth loop impedance tester
1985 Microprocessor-based high current test set
1989 Battery impedance test equipment (BITE)
1990 Automatic 10kV insulation power factor test set
1990 Microprocessor-based protective relay test set
1994 DSP-driven watthour meter test set
1996 Windows-based Testing Software Program
1999 Time-domain reflectometer with TX Null technology (TDR)
2000 Micro-weight Low Resistance Ohmmeter (DLRO)
2003 High power Relay test set with user features
2003 Multi-function tester with ergonomic design
2005 Noise immune 10kV insulation tester
2007 Loop impedance in an RCCB electrical test circuit tester [42]
2009 Three-phase transformer turns ratio test sets (TTR)
2010 Transformer ohmmeter (MTO)
2010 Cable fault location system (PFL)
2011 Automatic 12kV insulation power/dissipation factor test set (DELTA)



SMT machines at Dover site

Megger Group has manufacturing sites and sales centres in several countries worldwide. The main production sites are in: Dover, Dallas, Valley Forge and Täby.

Certificates of Conformity are supplied with most instruments. Depending on product and site the metrology can be traceable to:

Dover site has its own EMC laboratory and SMT machines. However, many of the mechanical parts are purchased from other suppliers. (This was one of the factors why production of AVO Model 8 was discontinued.)

All manufacturing sites have ISO 9001:2000 and Dover and Täby sites are certified to ISO 14001.

Main production and sales sites of Megger Group Ltd

Sales and technical support

The Group has over 1000 distribution points in 132 countries. 85% of sales are made via the distribution network. There are sales centres in several countries and products are also sold via specialised distributors including RS Components and more recently Test Equipment Connection Corporation. [43] [44]

There are total of 15 sales and technical support offices in the USA, Canada, Dover, Paris, Mumbai, Sydney, and Bahrain.[45]

Types of products

Megger product range (Dover site)
Megger "power" products
Megger insulation testers

Megger produces over 1000 products in around 25 groups:[46]

  1. Battery test equipment
  2. Cable fault locating equipment
  3. Circuit breaker testers
  4. Data communication testers
  5. Fiber optic testers
  6. Ground resistance testers
  7. Insulation power factor testers
  8. Insulation resistance testers
  9. Line testing equipment
  10. Low resistance ohmmeters
  11. Motor and phase rotation testers
  12. Multimeters
  13. Oil testers
  14. Partial discharge test equipment
  15. Portable appliance and tool testers
  16. Power quality instruments
  17. Recloser test equipment
  18. Relay testers
  19. T1 network testers
  20. Tachometers and speed measurement instruments
  21. Time domain reflectometry testers
  22. Transmission impairment testers
  23. Watt-hour meter tester
  24. States terminal block and test switches
  25. Professional hands-on technical and safety training programs

The equipment is roughly divided into three groups: Power, Building and Wiring, and Telecommunications.


In the UK, Megger regularly sponsors first year projects at the University of Kent, [47] as well as collaborating with other universities.


Megger donated 5% of its Chinese sales revenue (for three months) to the local Red Cross after the 2008 Sichuan earthquake. This was also preceded with 15% reduction on all their equipment sold in China immediately after the earthquake. [48]

Over $9,000 of electrical testing equipment has been donated to Mesalands Community College’s North American Wind Research and Training Center (NAWRTC). [49]

A blood donation vehicle comes regularly to the Megger's site at Dover.[50]


  1. ^
  2. ^, Evershed & Vignoles Ltd
  3. ^ / about
  4. ^ US Patent 611,809 (4 Oct 1898)
  5. ^ US Patent 642,743 (6 Feb 1900)
  6. ^ US Patent 639,849 (26 Dec 1899)
  7. ^ Megger trademark
  8. ^ US Patent 1,358,179 mentioning Megger (1920)
  9. ^ Megger is "well-known" by 1927, US Patent 1,616,387
  10. ^ Vintage Communication Pages, Major Megger
  11. ^ Megger advert from 1943
  12. ^ Megger MJ15
  13. ^ / Evershed_and_Vignoles
  14. ^ / Evershed_and_Vignoles
  15. ^ / Sullivan
  16. ^ H.W. Sullivan Limited in the Companies House
  17. ^
  18. ^ a b / AVO
  19. ^ / AVO
  20. ^ / Megger bids farewell to AVO 8
  21. ^ / AVO Model 8 retires after 58 years
  22. ^ / AVO Training Institute Inc
  23. ^ / about
  24. ^ / AVO Training Institute in Paris
  25. ^ AVO Electrical Engineering Division
  26. ^ / Thorn Electrical Industries
  27. ^ / Automatic Coil Winder and Electrical Equipment Company
  28. ^ / Megger
  29. ^ / about
  30. ^ / about
  31. ^ Power DB
  32. ^ / about
  33. ^ / GE Sells Programma to Megger
  34. ^ / about
  35. ^ Pax joins Megger Group
  36. ^ / trademark usage
  37. ^
  38. ^
  39. ^ Nick Hilditch (Editor), Electrical Tester, Quarterly published by Megger, Spring 2008
  40. ^ Meg Megger clocks up a century of innovation
  41. ^ Product design company chosen for Megger
  42. ^ Patent 7271577: Testing loop impedance in an RCCB electrical test circuit by Smithson, Edward, Xu, Rongkai, Mandala, Agung Kurniawan Sadya, Chin, Freddie Yun Heng
  43. ^ Megger products in RS Components
  44. ^ Test Equipment Connection Corporation announces new distribution agreement with Megger
  45. ^
  46. ^ E. Langan et al., A guide to low resistance testing, Megger, MEG-429_V-04/MIL/2.5M/7.2005
  47. ^ Kent student wins Megger prize
  48. ^ Megger Responds to Chinese Disaster
  49. ^ Megger donates equipment to NAWRTC
  50. ^

External links


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Look at other dictionaries:

  • Megger Group Limited — Rechtsform Gründung 5. Februar 1895 Sitz …   Deutsch Wikipedia

  • Megger — Group Limited Unternehmensform Gründung 5. Februar 1895 Unternehmenssitz …   Deutsch Wikipedia

  • Multímetro — Polimetro de piedra y polímetro digital. Midiendo con el polímetro …   Wikipedia Español

  • Täby — Täby …   Deutsch Wikipedia

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