Model 400A Soil Resistivity Meter by M.C. Miller

Obtain Accurate Soil Resistivity Measurements


In order to fulfill the industry's need for an analog soil resistivity meter that is affordable, available, and meets M.C. Miller's high standards, we are proud to introduce the M.C. Miller 400A Analog Soil Resistivity Meter.

The Miller 400A operates exactly like the Nilsson 400 4-Pin Soil Resistance Meter with regard to resistance range selection, null balancing, etc. Consequently, a technician who is familiar with operating a Nilsson 400 will not have to learn any new procedures to operate the Miller 400A.

The Miller 400A has an IP67 rating for dust and water intrusion, and it runs on a set of easily replaceable C-size alkaline batteries. Also, the Miller 400A is built using state-of-the-art components that are readily available, which means that we can respond to our customers' needs in a timely fashion.

Note that the Miller 400A does not fit inside the existing MC Miller soil resistivity test kit case. MC Miller is in process of developing a new case that will accommodate the kit items including the new Miller 400A.

The Miller 400A Users Manual is posted on this website, providing technical details on the operation of the unit and its various applications.



  • Rugged, lightweight case.
  • Safe to use on wet ground.
  • Weatherproof, even with lid removed.
  • IP67 rating for dust and water intrusion.
  • Convenient case lid removal for ease of movement, with test leads attached, to new measurement locations.
  • Uses Wenner method.
  • Resistance measurement range from 0.01ohm (0.010) to 1.1 Mohm (1.1 MΩ).
  • Resistance measurements not affected by stray interference signals that may be present in the earth during the measurements, as made possible narrow band-pass filters.
  • Runs on a set of replaceable C-cell alkaline batteries.
  • No need to periodically recharge the unit or to plug the unit into a power source.
  • Quick turn-around for calibration.
  • Manual online for easy reference.
  • In stock - Order today!


Whether you need to measure soil resistivity or the resistance-to-earth of an electrode, such as a ground rod or an anode, the Miller-400A has you covered:

  • Determine the average earth resistivity to a specific depth (4-electrode application).
  • Determine the resistivity of a soil sample, or of a liquid, via an electrolyte (soil/ liquid) box (4-electrode application.
  • Measure the resistance-to-earth of a buried electrode, such as a ground rod, or an anode, for example  (3-electrode application).
  • Measure the resistance between two buried electrodes, such as two ground rods, or two anodes (2-electrode application).

For more information and connection diagrams, please see the Miller 400A Users Manual




Storage temperature range (with batteries installed): -30oC to 50oC (-22oF to 122oF)
Operating temperature range: -20oC to 54oC (-4oF to 129oF)
Weight: 7 lbs (3.175kg)
Width: 12in (30.5cm)
Length: 10in (25cm)
Height: 5in (12.5cm)