Troubleshooting 9:2
CP 1 – Cathodic Protection Tester Course Manual
© NACE International, 2000
07/01/04
Anode
Foreign
Structure
Protected Structure
Metallic
Short
Anode
Foreign
Structure
Protected Structure
Metallic
Short
Figure 9.1 Illustration of Shorted Structure
Testing a Pipeline
Current profile
In a pipeline system, it may be possible to locate a short by tracing current
flow. In a distribution system, where metallic service lines are electrically
continuous with the mains, a failed isolating fitting at the meter will cause a
short circuit. Cathodic protection current lost to other structures through
this short will return to the main on the service line. Using a clamp-on
ammeter, service lines in the affected area can be tested. Current flow back
to the main will be found on the shorted service line. See Figure 9.2.
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