To establish a standard position in which to place the electrode to take the standard pipe-to-soil voltage measurement, for cathodic protection monitoring. at a test post.



INSTRUMENTATION. AND EQUIPMENT

High resistance voltmeter. Cu/CuSO4 electrode. Two lengths of flexible cable, each fitted with a voltmeter connector and a crocadile clip. Digging tool Field notes Report forms

MATERIALS

One 500mm length of 50mm dia. pipe, made of non-conductive material.



METHOD

1.1 Place the electrode in the ground.

1.2 Connect the electrode to the positive pole of the voltmeter.

1.3. Connect the negative pole of the voltmeter to the pipeline test point connection.

1 4. Move the electrode in 1/2 m steps at a 1m radius around the test post.

1.5. Record the lowest and highest voltage readings.

1.6. Step the electrode at 100mm intervals,in a grid pattern, at the vicinity of the lowest reading.

1.7 Mark the point of electrode contact which shows the lowest voltage.

1.8 Bury a 1/2m length of 100mm dia. pipe, vertically, at this point, with 50mm showing above ground level

1.9 Fill the pipe with the spoil from excavation and compact to original level.

1.10. Place the electrode firmly in the open top of the buried pipe.

1.11. Record the voltage.