Mississippi Administrative Code › Title 11 - Mississippi Department of Environmental Quality › Part 5 - Underground Storage Tank Regulations › Chapter 2 - Mississippi Commission on Environmental Quality Underground Storage Tanks Regulations Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks (UST) (Adopted March 22, 1989; Amended August 25, 2011, Last Amended August 23, 2018) › Appendix 11-5-2-280.1 - GUIDELINES FOR THE EVALUATION OF UNDERGROUND STORAGE TANK CATHODIC PROTECTION SYSTEMS › Appendix 11-5-2-280.1-E

Current through June 25, 2024
CONTINUITY TESTING PROCEDURE FOR
							 GALVANIC/IMPRESSED CURRENT CATHODIC PROTECTION SYSTEMS
Fixed Cell Moving Ground Continuity Test
							 Procedure
1. Place reference electrode in contact with the soil
							 at a location remote (25 100 feet) from all cathodically protected structures.
							 You must ensure that the remote reference electrode placement is not in
							 proximity to any other cathodic protection systems (e.g. natural gas pipelines)
							 or directly over any buried metallic structure in order to minimize the chances
							 of unwanted interference.
2. Be sure that reference electrode is firmly placed
							 in moist soil and is not in contact with any vegetation.
3. Connect reference electrode to the negative
							 terminal of voltmeter using a long spool of suitable wire.
4. Connect positive lead wire to voltmeter. This lead
							 wire should have a sharp test prod (scratch awl or similar) in order to assure
							 good contact with the metallic structures under test.
5. Place voltmeter on 2 volt DC scale.
6. Contact each buried metallic structure with the
							 positive test lead without moving the reference electrode. Typical items that
							 would be tested during a continuity survey include: all tanks, tank risers,
							 submersible pump heads, piping, flex connectors/swing joints, vent lines,
							 electrical conduits, dispensers, utilities, etc.
7. Obtain voltage for each component and record on
							 MDEQ continuity testing form.
8. Voltages for each component that is tested must be
							 obtained as quickly as possible since the observed potential can change over
							 time. This is because the conditions in the soil where the reference electrode
							 is placed can change over a relatively short period of time.
Fixed Cell Moving Ground Data
							 Interpretation
* If two or more structures exhibit potentials that
							 vary by 2 mV or less, the structures are considered to be electrically
							 continuous.
* If two or more structures exhibit potentials that
							 vary by 10 mV or greater, the structures are considered to be electrically
							 isolated.
* If two or more structures exhibit potentials that
							 vary by more than 2 mV but less than 10 mV, the result is inconclusive and
							 further testing (point-to-point) is necessary.
Point-to-Point Continuity Test Procedure
1. Turn off power to rectifier if testing an impressed
							 current system. This is necessary to obtain accurate results.
2. Connect test leads to voltmeter. Both test leads
							 should have a sharp test prod or suitable clip lead in order to make good
							 contact with tested structures.
3. Place voltmeter on 2 volt (or lower) DC scale.
4. Connect one voltmeter test lead to one of the
							 structures for which continuity is being tested and connect the other voltmeter
							 test lead to the other structure that is being tested.
5. Record voltages observed on each of the two
							 structures that are being compared and record on MDEQ continuity testing form.
Note: Testing with this method does not require a
							 reference electrode. The two structures of interest are simply connected in
							 parallel with the voltmeter and a determination made as to whether or not any
							 potential difference exists between them.
Point-to-Point Data Interpretation
* If the voltage difference observed between the two
							 structures is 1 mV or less, this indicates that the two structures are
							 considered to be electrically continuous with each other.
* If the voltage difference observed between the two
							 structures is 10 mV or greater, this indicates that the two structures are
							 considered to be electrically isolated from each other.
* If the voltage difference observed between the two
							 structures is greater than 1 mV but less than 10 mV, the result is inconclusive
							 and further testing beyond the scope of this document is necessary.