Cathodic Protection
Remake batch 26: rewritten from scratch under the authoring cheatsheet with datasheet constraints; neighbors re-pointed to the new scope boundaries; the electrical code is now the adopted-electrical-code project fact
Showing changes from Rev 1
to Rev 2
in Cathodic Protection.
---
title: Cathodic Protection
category: Process / Piping
description: >
When to use: Galvanic and impressed-current cathodic protection of buried and submerged metallic structures inside the fence of a water treatment plant, a wastewater treatment plant, a pump station, or an industrial process facility, read together with [[sync/common-work-results-process]]: buried ductile iron and steel yard piping with its valves and fittings, the interior submerged surfaces and the bottom exterior of steel water storage tanks, steel well casings, and the buried steel structures and sheet pile the drawings assign to the system. Covers the corrosivity survey, the design responsibility, the criteria of protection, galvanic anodes and their backfill, rectifiers, impressed-current anodes and anode beds, test stations, permanent reference electrodes and coupons, the joint bonds that make a gasketed line one conductor, electrical isolation and its test, the decoupling device between a protected structure and the grounding electrode system, interference and stray current mitigation, commissioning from the native survey through the final potential survey, the commissioning report, and the surveys that follow.
− Not intended for: The pipe, its coating, its polyethylene encasement, and the installation of the joint bonds this standard specifies ([[sync/ductile-iron-process-piping]] and [[sync/steel-and-stainless-process-piping]]); the tracer wire on plastic piping, which locates the line and is not a test lead ([[sync/plastic-process-piping]]); the tank itself, its interior lining, and the hand holes, reference electrode fittings, and rectifier mounting pad and conduit sleeve it provides ([[sync/water-storage-tanks]]); the well casing as a structure ([[sync/water-wells]]); the factory sacrificial anodes and the STI R051 commissioning of a steel underground fuel tank ([[sync/fuel-dispensing-and-storage-tanks]]); buried steel gas piping, which stays with the gas standard and the serving utility ([[sync/natural-gas-piping]]); the anode inside a water heater ([[sync/water-heaters]]); galvanic anodes embedded in concrete repairs ([[sync/concrete-repair-and-restoration]]) and cathodic protection of reinforcing steel in concrete under NACE SP0290, which is not yet owned by a SynC standard; electrically isolated post-tensioning tendons ([[sync/post-tensioned-concrete]]); lightning protection ([[sync/lightning-protection]]); shop galvanizing and sacrificial zinc coatings ([[sync/shop-painting-and-galvanizing]]); the building ground system and the safety bonding of metallic piping ([[sync/grounding-and-bonding]]); the rectifier branch circuit, its disconnect, its conductors, and its raceway ([[sync/common-work-results-electrical]], [[sync/conductors-and-cables]], and [[sync/raceways-and-conduit]]); and marine structures and the transmission mains and pipelines beyond the plant fence that a pipeline operator's corrosion program governs, which are not yet owned by a SynC standard.
+ Not intended for: The pipe, its coating, its polyethylene encasement, and the installation of the joint bonds this standard specifies ([[sync/ductile-iron-process-piping]] and [[sync/steel-and-stainless-process-piping]]); the tracer wire on plastic piping, which locates the line and is not a test lead ([[sync/plastic-process-piping]]); the tank itself, its interior lining, and the hand holes, reference electrode fittings, and rectifier mounting pad and conduit sleeve it provides ([[sync/water-storage-tanks]]); the well casing as a structure ([[sync/water-wells]]); the factory sacrificial anodes and the STI R051 commissioning of a steel underground fuel tank ([[sync/fuel-dispensing-and-storage-tanks]]); buried steel gas piping, which stays with the gas standard and the serving utility ([[sync/natural-gas-piping]]); the anode inside a water heater ([[sync/water-heaters]]); galvanic anodes embedded in concrete repairs ([[sync/concrete-repair-and-restoration]]) and cathodic protection of reinforcing steel in concrete under NACE SP0290, which is not yet owned by a SynC standard; electrically isolated post-tensioning tendons ([[sync/post-tensioned-concrete]]); lightning protection ([[sync/lightning-protection]]); shop galvanizing and sacrificial zinc coatings ([[sync/shop-painting-and-galvanizing]]); the building ground system and the safety bonding of metallic piping ([[sync/grounding-and-bonding]]); the rectifier branch circuit, its disconnect, its conductors, and its raceway ([[sync/common-work-results-electrical]], [[sync/enclosed-switches-and-disconnects]], [[sync/conductors-and-cables]], and [[sync/raceways-and-conduit]]); and marine structures and the transmission mains and pipelines beyond the plant fence that a pipeline operator's corrosion program governs, which are not yet owned by a SynC standard.
---
…24 unchanged lines
- shop galvanizing, zinc-rich primers, and other sacrificial coatings, under [[sync/shop-painting-and-galvanizing]]
- the grounding electrode system, the equipment grounding of the rectifier, and the electrical safety bonding of metallic piping and tanks, under [[sync/grounding-and-bonding]]
−- the rectifier branch circuit and its disconnect, under [[sync/common-work-results-electrical]]; its conductors, under [[sync/conductors-and-cables]]; its raceway, under [[sync/raceways-and-conduit]]
+- the rectifier branch circuit and its disconnect, under [[sync/common-work-results-electrical]], the disconnect as a product under [[sync/enclosed-switches-and-disconnects]]; its conductors, under [[sync/conductors-and-cables]]; its raceway, under [[sync/raceways-and-conduit]]
- trench excavation, dewatering, and backfill above the pipe zone, under [[sync/earthwork]]
- marine structures, and the water transmission mains and pipelines beyond the plant fence that a pipeline operator's corrosion program governs, not yet owned by a SynC standard
…487 unchanged lines
```
−### The AC branch circuit, its overcurrent protection, and the disconnecting means within sight of the rectifier shall be furnished under [[sync/common-work-results-electrical]], the conductors under [[sync/conductors-and-cables]], and the raceway under [[sync/raceways-and-conduit]], and the Contractor shall reconcile the rectifier's input current against the circuit shown before the rectifier is released for manufacture.
+### The AC branch circuit, its overcurrent protection, and the disconnecting means within sight of the rectifier shall be furnished under [[sync/common-work-results-electrical]], the disconnect as a product under [[sync/enclosed-switches-and-disconnects]], the conductors under [[sync/conductors-and-cables]], and the raceway under [[sync/raceways-and-conduit]], and the Contractor shall reconcile the rectifier's input current against the circuit shown before the rectifier is released for manufacture.
### Each rectifier shall be factory tested at full rated output for not less than one hour, with the input and output voltages and currents, the efficiency, and the temperature rise recorded on the factory test report.
…595 unchanged lines
## A spare anode is installed when the annual survey finds an anode consumed or a structure below the criterion, and it is only useful if it is the alloy and weight of the installed ones; the count is set by how many anode groups the system has and how far the site is from a supplier, and a system with no galvanic anodes has none. {note}