A switching device, usually GPS-synchronized, that cuts current from rectifiers, bonds or anodes on a repeating cycle so surveyors can read on and instant-off potentials. Every source affecting the area must switch in step, and the off period is kept short, typically under a second in each cycle, so the pipe does not depolarize. Survey crews install them before a close interval survey and pull them when the job is done.
Set the interrupters on all three recs, 800 on and 200 off, GPS synced, before the CIS crew starts Monday.
Confirm every interrupter is in sync before starting. One rectifier switching out of step makes every off reading on the section wrong.
Also heard as
- current interrupter
- GPS interrupter
Related terms
Instant-off potential
Structure potential read in the split second after CP current is switched off, free of IR drop.
Ons and offs
Survey slang for paired on and instant-off potential readings taken while rectifiers are being interrupted.
CIS
Close interval survey: potential readings taken every metre or so along a pipeline to find protection gaps.
Rectifier
Transformer-rectifier unit that turns AC power into adjustable DC current for an impressed current CP system.