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Online Monitoring Solutions for Critical Electric Transmission and Distribution Equipment

  • Always Listening
  • Non-Invasive
  • Optimized Data
  • Scalability

Online Monitoring Solutions for Critical Electric Transmission and Distribution Equipment

Always Listening

The 4Site is listening in real-time for the first sign of high frequency sounds produced by arcing, tracking & corona.


Utilizing the power of airborne ultrasound, there is no contact with the electrical components of the equipment being monitored, making installation safer and easier.

Optimized Data

The 4Site is designed to reduce data overload and alert by exception.  While the 4Site is always listening, it will only transmit informative data if a threshold is crossed and eliminating the need to transmit healthy data.


Each 4Site is designed to monitor up to 4 cabinets simultaneously in one unit.

Continuous Monitoring of Electrical Assets

When electrical systems such as switch gear, transformers, insulators or disconnects and splices fail, the results can be catastrophic. The average cost of a critical electrical asset failure is greater than $500K per event and with the aging equipment and less than 5% of critical electrical assets have continuous monitoring integrated, the time is now to efficiently monitor your critical electrical assets for the three common failure modes, arcing, tracking & corona.

Online continuous ultrasound inspection can be performed at all voltage levels (low, medium and high) and is used to detect:

  • Corona
  • Partial discharge or tracking
  • Arcing
  • Mechanical vibrations (transformers)

How Ultrasonic Electrical Inspection Works

Partial discharge/tracking, arcing and corona all produce ionization which disturbs the surrounding air molecules.

The 4Site detects high frequency sounds produced by these emissions. The specific sound quality of each type of emission and the intensity of the signal is recorded. These sounds are analyzed through ultrasound spectrum analysis software for diagnosis & reporting.

Normally, electrical equipment should be silent, although some equipment such as transformers may produce a constant 50 cycle hum, or some steady mechanical noises.

These should not be confused with the erratic, sizzling frying, uneven and popping sound of an electrical discharge.

Specifications overview 4Site

Stainless Steel; Dimensions: 9”x6”x3” (22.8cm x 15.24cm x 7.62cm)
Weight: 4.7 lbs. (2.1 kg)
Power input
24V, 1 amp (conditioned)
Solid State Analog and SMD Digital with temperature compensation and true RMS conversion
Frequency Response
20kHz-100 kHz Centered around 40 kHz
Response time
Operating Temperature
32°F - 122°F / 0°C - 50°C
RAS piezoelectric, stainless steel housing
BNC out to BNC in (length: 25’ / 7.62 m, can be ordered up to 100 feet / 30,48 m).
Transducer Mount
Thread: female10/32
Ultratrend DMS 6.0 or higher

Brochures & Manuals


This product is suitable for

Electrical Inspection

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