Impressed current cathodic protection: a system in which a DC source, usually a transformer-rectifier, drives current from slowly consumed anodes into the electrolyte and onto the structure. Mixed metal oxide, high-silicon cast iron or graphite anodes last for decades, and output can be adjusted as coatings age and soil conditions change. ICCP covers long pipelines, tank farms and ship hulls that sacrificial anodes cannot, but it needs power, upkeep and interference control.
ICCP at the terminal is putting out 18 amps at 32 volts, up 4 amps on last year.
Also heard as
- impressed current
- IC system
Do not mix it up with
- Sacrificial anode: Sacrificial anodes generate their own current by corroding; ICCP anodes need a power source and are consumed very slowly.
Related terms
Rectifier
Transformer-rectifier unit that turns AC power into adjustable DC current for an impressed current CP system.
Groundbed
Group of impressed-current anodes buried in backfill that discharges rectifier current into the earth.
MMO
Mixed metal oxide anode: titanium coated with precious-metal oxides, the standard long-life ICCP anode.
Deep anode
Impressed-current groundbed with anodes stacked in a vertical hole drilled tens of metres deep or more.
Cathodic protection
Shielding buried or submerged steel from corrosion with DC current from sacrificial anodes or a rectifier.