The comprehensive range of Doble® market-leading test and measurement equipment will provide you with accurate diagnostic results, when you need it.  This will help you make the right decision about your critical electrical assets and to ensure the safety and reliability of your power system.

Offering solutions for In-Service Testing & Assessment, On-Line Monitoring and Off-Line Testing and Assessment of electrical assets, the Doble® range of equipment delivers solutions that will meet all your testing requirements.  With the M-Series range of equipment, Doble® has established their world-class reputation as a leader in the field for analytical tools and test methods to measure the quality and condition of high value electrical assets. The M series instruments and Doble® Test Assistant software are industry standards across the globe.


  • M7100 High Voltage Asset Analyser – Making testing simple, safe and efficient, the Doble®  M7100 is revolutionizing offline testing. It is designed to dramatically reduce the number of ladder trips and the amount of testing time; it automates numerous tests and houses the testing capabilities of numerous test sets in one box. With this tool, you can maximize outage periods by performing more maintenance during the hours previously devoted to testing.
  • M4100 Automated Insulation Analyser is the premier power apparatus and insulation test instrument. The Doble® M4100 Power Factor/Tan-Delta instrument features a unique combination of test capabilities and artificial intelligence analysis software trusted for its comprehensive testing options, safety features and measurement accuracy.
  • M5400 Sweep Frequency Response Analyser detects mechanical failure or movement of windings due to short circuits, mechanical stresses or transportation. Use the Doble® M5400 to ensure transformer performance, reduce maintenance costs and optimize service life.
  • TDR Series Circuit Breaker Test Instruments for the efficient and accurate testing of all types of circuit breakers, ensuring they are operating as designed. Doble’s TDR instruments and software are designed for ease of use for the field user and also contain powerful analysing features needed to make critical decisions about your circuit breakers. 
  • Doble®Test Assistant Software is the most comprehensive software tool for the collection, analysis and management of test results for the Doble® M-Series family of instruments. DTA6 includes remote access to stored data from your personal Doble® database for backup and asset management. 
  • Doble® Universal Controller™ is a rugged tablet computer powerful enough to operate Doble’s suite of high voltage test equipment and software solutions while being tough enough to withstand the rigors of electrical field testing. The DUC™ provides the processing power necessary to run advanced software in the field. It is designed for durability and is built to withstand the same tough requirements of Doble’s test equipment. Testing is even possible in full sunlight thanks to its bright, anti-reflective display.


  • DELPHI Portable Dissolved Gas Analyser is a powerful diagnostic tool to help you understand the health and condition of power transformers and other oil-filled equipment. The Delphi Portable, part of Doble’s line of DGA instruments, provides timely and actionable information on key dissolved gases in insulating oil. This portable device helps identify and track faults by monitoring composite gas levels and tracking individual gases when those levels change.
  • LCM 500 Leakage Current Monitor measures the condition of metal oxide surge arresters while the arrester is still in service. By measuring the resistive leakage current, the condition parameters of the metal oxide blocks can be compared and help to manage the risk of failure.
  • Partial Discharge & Dielectric Analysers to identify and locate insulation defects by combining radio frequency interference (RFI) and acoustic emission (AE). The Doble® Partial Discharge surveying equipment can detect and locate partial discharge (PD) in a few seconds. Designed for surveying live, high voltage apparatus and switchgear panels, its versatility makes it the perfect, multi-purpose tool for condition-based maintenance programmes.  


  • Intelligent Diagnostic for Bushing and Current Transformers – Doble’s Intelligent Diagnostic Devices (IDDs) detect abnormalities in bushing insulation and issue appropriate alerts. Bushings can fail slowly, giving you time to plan for replacement; they can also fail rapidly, leaving little time to act. With intelligent monitoring from Doble®, you can proactively manage risk in both situations and plan for replacements.
  • Dissolved Gas Analysers – The Doble® Delphi is a dissolved gas analysis (DGA) monitor designed to track transformer health by providing early warning signs of problems such as overheating, insulation degradation or mechanical movement within the unit. The Delphi provides this valuable information in real time, second by second.
  • Moisture Sensors – Determining the moisture in insulating liquids is an essential part of any comprehensive maintenance or diagnostic programme. The Doble® DOMINO line, with permanent mount and portable options, provides continuous, reliable measurement of the water content of electrical insulating liquids and other types of oils. The DOMINO sensor measures moisture in oil in terms of ppm and relative saturation, as well as temperature.