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Permanently Installed AgCl

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AccuRef 60 & AccuRef 20 Permanently Installed Silver Chloride Reference Electrodes

These electrodes represent state-of-the-art technology and are a result of MCM’s commitment to on-going research and development for the Cathodic Protection industry.



  • Electrode: Permanent Silver/Silver Chloride Electrode.
  • Applications: Direct burial in soil, with or without chloride ion contamination.
  • Electrode Potential: In the range, 240mV ±10mV, versus SHE @ 25oC**
  • Filling Solution: Saturated KCl plus additives **
  • Low Freezing Point: –20oC.
  • Design Life: 60 years (AccuRef 60), 20 years (AccuRef 20).
  • Purity: High purity Ag, AgCl, KCl and triple de-ionized H2O.
  • Cost: Less expensive than most Copper Sulfate permanent electrodes.
  • Tip: Moisture absorbent ceramic tip.
  • Evaporation: Will not dry out at low humidity and/or high heat.
  • Wire: 25 feet of AWG 12 lead wire; cross-linked Polyethylene jacket, direct burial, low leakage, 600V, 90oC Rating, USE-12/RHH/RHW-2. Longer lengths of wire are available.
  • Electrical Contact Surface Area: Approx. 16.4 square inches (a cylindrical surface, 1.5 inches in diameter and 3.5 inches in length).

** AccuRef silver/silver chloride electrodes are not subject to contamination even in high chloride ion content soil due to the use of saturated KCl in the filling solution. The electrode potential is in the range 240mv ±10mV versus SHE @ 25oC, rather than around 200mV versus SHE @ 25oC, as a consequence of the additives included in the filling solution. The additives are responsible for the strongly-hygroscopic nature of the electrodes (they do not dry out even in very dry soil conditions and for the depressed freezing temperature (-20oC).

If necessary, readings taken with AccuRef electrodes can be adjusted to either the accepted saturated silver/silver chloride electrode potential or to the accepted copper/saturated copper sulfate solution electrode potential, based on the calibrated electrode potentials associated with the AccuRef electrodes (averaging around 240mV versus SHE, typically). For example, if the structure-to-soil reading taken with an AccuRef electrode, having a 240mV versus SHE potential, is -1,265mV, the adjusted readings would be as follows ***:

AccuRef reading = -1,265mV
Reading adjusted to saturated Ag/AgCl electrode potential = -1,225mV [240mV - 200mV + (-1,265mV)]
Reading adjusted to Cu/CuSO4 electrode potential = -1,341mV [240mV - 316mV + (-1,265mV)]