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Half-Cell Potential – Elcometer 331

Half-Cell Potential Elcometer 331

We stock the Elcometer 331 BH and SH. These are cover meters capable of Half-Cell potential measurement.

A separate Half-Cell potential kit is available to plug in to the units. These are available in a copper/copper sulphate or silver/silver chloride solution. Half-Cell potential is an electrochemical technique used to assess the severity of corrosion in reinforced concrete structures.

You can set the cover meter in half-cell potential mode via the menu on the 331 unit. In this mode the cover meter acts as a voltmeter measuring the potential difference between the steel reinforcement in the concrete structure and a reference electrode (copper/copper nitrate or silver/silver chloride).


Use the 331 as a cover meter to detect and locate a reinforcing bar. Then use a drill/breaker to expose the bar. (Enough to clip the supplied bulldog clamp to the bar).

Mark out a grid on the concrete. Typical spacing is 1 meter by 1 meter, although this may be reduced if localised corrosion is suspected.

Ensure the test area is suitable wet, this can be the whole grid area or just the measurement positions themselves.

Ensure the cover meter is in half-cell mode. Attach the bulldog clip (red cable) to the exposed bar and plug the other end into the red terminal on the cover meter. You can plug in via the extension reel if required. The black cable attaches to the bottom of the half-cell probe and the the black terminal on the cover meter.

Remove the black cap from the probe and store safely. Press the probe against the concrete surface at the first point of your predetermined test grid. If you are satisfied with the reading, log it and move on to the next test point.

You can use the the SH unit to record each result by entering ‘batch mode’. The results will then be saved to the unit memory.

Useful links

Operating Instructions

Alternative half-cell kit

331 Re bar detector

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331 Half-Cell potential meter




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