Ref-Check VPR (Voltage Potential Restoration) Test Instrument by Farwest Corrosion

Secure Accurate CP Readings with Ref-Check VPR.

No CP Technician should be without this instrument!

Cathodic Protection (CP) solutions require accurate voltage potential or structure-to-soil readings. The Ref-Check VPR is the next step in the Farwest Ref-Check product line designed to overcome false or low potential readings from a cathodic protection reference electrode (CPRE).

The Ref-Check VPR can take accurate potential readings even with a compromised CPRE, which no longer requires replacement. You can now trust the provided potential reading even if the CPRE is not performing to original specifications.  In addition, the Ref-Check VPR can confirm good contact-to-earth resistance of a portable CPRE and/or CP coupon.

The Ref-Check VPR works in conjunction with a standard digital multimeter (DMM) via the included dual banana plug cord. When engaged, the Ref-Check VPR increases the circuit input resistance from 10 million ohms to approximately 5 billion ohms, making it over 500 times more sensitive.  This allows a standard DMM to provide much higher accuracy because, with the Ref-Check VPR, it provides near zero meter loading.

In addition, when connected to the DMM, the Ref-Check VPR remains out of the circuit until the "Press to Read" button is engaged.  This allows a CP technician to leave the Ref-Check VPR connected to the DMM during normal CP testing.


All DMMs will impose a load, referred to as "meter loading”, on the CPRE.  This load affects CPRE accuracy even under the best conditions.  Most professional grade DMMs have a 10 meg (million) ohm input resistance.  This may seem high but when used to measure very sensitive (high resistance) circuits, such as a compromised reference electrode (due to age or lack of moisture), the meter imposes a load on the circuit that can result in a very large structure-to-electrolyte potential error. 




  • Fully solid state 
  • Rugged and lightweight
  • Single button operation
  • Built-in battery check
  • Under 3-second response time
  • Built-in accuracy verfication
  • Compact size: 4.7" x 3.0" x 1.2"
  • Mearsuring range:  +/- 5 volts DC
  • No third-party calibration required
  • Long-life battery provides over 50,000 reads
  • Works with a standared digital multimeter (DMM)
  • Fits in your tool bag 

The Ref-check VPR provides an immediate return-on-investment.  Accurate potential readings from a compromised stationary CPRE can elimnate the need for the CPRE's replacement, saving thousands of dollars in labor and material.


With the new Ref-Check VPR, you can now be confident in the structure-to-soil potential readings you receive.  Plus, you can effectively extend the life of compromised CPREs and lower your operating costs.

What's Provided With Your Order? 

With the purchase of your Ref-Check VPR, you'll receive:

  • A professional grade, stackable dual test lead interconnect cable
  • Operating instructions
  • A lifetime warranty against defects and workmanship


The Ref-Check VPR connects between the voltage input of a DMM, the CPRE and the structure test lead cable to convert a standard DMM into a near zero loading voltmeter.  

  1. After the cable leads are connected to the structure under test, a negative voltage reading should be displayed on the DMM. If reading displayed is not negative, either the test cable leads are incorrectly connected or the structure under test has shifted to positive.  (This would require further investigation).

NOTE: In order for the Ref-Check VPR to operate properly, the cable leads must be installed correctly.

  1. The initial voltage displayed is a direct reading from the DMM as the Ref-Check VPR provides an electrical by-pass until the “PRESS TO READ” button is pressed.
  2. To check the quality of CPRE contact resistance, press the “PRESS TO READ” button. If there is any appreciable contact-to-earth resistance from the CPRE, the DMM will now display the corrected potential. If the contact-to-earth resistance of the CPRE is good/sufficiently low, little if any change in the displayed voltage will be evident.
  3. As noted above, the Ref-Check VPR can be used to confirm good contact-to-earth of a portable CPRE as well as coupons during routine surveys.


The Ref-Check VPR is warranted against defects in materials and workmanship for the lifetime of the device. The warranty does not apply to any products which have been subject to obvious physical damage, misuse, neglect or abnormal conditions of operations.

(Size: 0.22 MB)
(Size: 2.64 MB)