Using a pulsed DC current on the pipeline, the survey investigates voltage gradients associated with external coating defects, using two earth contact probes and a sensitive centre-zero voltmeter. Severity of defects can be assessed and effectiveness of cathodic protection at the defect determined.

A survey technique to detect external coating defects, which employs an AC signal injected onto the pipeline where it compares the potential gradient between two mobile earth contacts. At coating defects, increases in voltage gradient occurs which are noted and recorded as the survey progresses.

As described through NACE standard SP0502, ECDA is a four turn-key process that covers the line through examination of places on the pipe where anomalies could form and thus corrode. This four step ECDA procedure which EESB strictly follows with NACE standard is as follows:

• Pre-Assessment
• Indirect Inspection
• Direct Examination
• Post Assessment

As described through NACE standard SP0502, ICDA is a four turn-key process that covers the line through examination of places on the pipe where liquids could form and thus corrode. This four step ICDA procedure which EESB strictly follows with NACE standard is as follows:

• Pre-Assessment
• Indirect Inspection
• Direct Examination
• Post Assessment

Extreme levels of electric current in AC and DC Transmission Pipelines can induce nearby assets. These current travels along the structure and lands on ground level which can destroy the pipe through gouges, cracks, and blowouts. EESB provides mitigation of AC and DC from damaging your lines. We then monitor these lines to test for any stray current of impact from AC and DC.