Any buried metallic structure owned by someone else: another company's pipeline, a water main, a cable sheath or a tank. Foreign lines matter because one operator's CP current can corrode the other's pipe where it discharges, so crossings get test stations with leads on both lines. Operators run joint interference tests and agree on bonds or mitigation, often through local corrosion coordinating committees.
Foreign line at MP 8 is picking up our current, set up a joint test with their CP tech.
Also heard as
- foreign structure
- foreign pipeline
- third-party line
Related terms
Interference
Unwanted DC or AC current picked up from another source, which corrodes a structure where it leaves.
Bond
Wire or cable connection that ties two metal structures together electrically, often to control CP current.
Test station
Above-ground post or box with wires bonded to a buried structure, used to take CP readings.