Lutron GU-3001 for Domestic Evaluation of Magnetic Fields


ADM recently sold a Lutron GU-3001 to a domestic customer wanting to test the magnetic field strength around their home. This customer was concerned about a DC distribution cable that was running just outside the property boundary. 

Any electrical and electronic equipment produces a magnetic field as part of its operation.  

When current flows in a conductor, a magnetic field is generated. The strength of the magnetic field is proportional to the current flowing in the conductor.  

This is usually no problem as the small fields produced are of little concern. However, when a large current flow is involved, the magnetic field strength can be higher and a cause for concern is possible.  

With the right instrument, the magnetic field can be measured and compared with standards and safety limits to confirm there is no risk to people’s health. 


The Lutron GU-3001 is a precision DC/AC milligauss Magnetometer that will allow measurements to be performed with precision and accuracy. The specifications are as follows:

  • High sensitivity sensor 
  • For industrial, mechanical, material, electrical, and laboratory applications 
  • DC and AC magnetic field measurement 
  • Wide measure range: ± 3,000 milligauss. 
  • Can detect the magnetic fields as small as 0.1 milligauss. 
  • N pole/S pole indicator. 
  • Separate probe for easy operation and convenient remote measurement. 
  • High precision magnetometer can measure the absolute Earth's magnetic field as reference 
  • Zero adjustment button for relative measurement 
  • Large S-TN type LCD, high contrast, easy readout 
  • Data hold function for freezing the desired value on display. 
  • Records maximum and minimum readings with recall. 
  • RS232/USB computer interface 
  • Heavy duty & compact housing with hard carrying case 
  • Auto shut off to save battery life. 
  • Power supply from batteries or DC 9V adapter 

Lutron GU-3001 milligauss magnetometer


The GU-3001 was purchased from ADM and used by our customer to look at the relevant magnetic fields in and around the home.  

Measuring the magnetic field at the edge of the boundary showed fluctuating results.  

As the probe is moved around, the magnetic field measured would have varied depending on the alignment of the sensor with the magnetic flux produced by the cable.  

The magnetic field strength would have been varying in proportion to load changes on the powerline.

magnetic fields from power transmission line


A third party was also involved and suggested that a Zero Gauss chamber should be used to reduce the fluctuation in the readings.  

However, this is not correct. The probe would have been responding to changes in the probes position as it was moved and the changing load on the cable. 

A Zero Gauss chamber is as its name implies, a chamber that the probe is inserted into to shield the probe from magnetic fields. It is used to adjust or check the ZERO calibration to confirm the instrument is reading zero when no fields are present. 

Zero gauss chamber


So, to clarify the measurement in this case the probe is carefully moved around, and the Peak is noted. The Peak should correspond to where the probe is aligned with the magnetic lines of flux from the source. The Peak reading can be compared with the relevant standards to confirm the magnetic field is or isn’t within safe limits. 

ADM is happy to help customers perform measurements in their own home or business over the telephone.  

There are many variables to consider when making measurements and sometimes a professional approach is required by hiring the services of a consultant, who specialises in taking such measurements.  

They will produce a report that confirms the maximum field strength for the measurement area concerned. It is important to confirm that the person doing the measurement is using a calibrated meter. This means that the accuracy of the measurement equipment has been tested against a known source and is certified to be correct. The details of the meter and calibration report should be on the report that you receive. 

Sometimes a quality meter can help you to feel comfortable in your home or business. By purchasing a meter from ADM, you will have technical support to complete the measurement yourself.  

However, you will need to understand the scientific principles involved to be able to perform and relate to the measurements. 

Please contact ADM Nuclear Technologies to discuss your requirements with one of our professional team now. 

16 June 2022