JANUARY 31 2003
taken at the same locations to determine if changes have occurred.
If potential measurements do not satisfy Chapter 6 criteria and the current
output meets the current requirement from the last survey, adjust or supplement the
system as necessary. After 30 days, perform a water tank calibration (refer to
RECTIFIER OPERATIONAL INSPECTION. The purpose of the rectifier
operational inspection is to determine the serviceability of all components required to
impress current to the anodes of the impressed current system. The inspection should
be thorough to ensure dependable current until the next inspection.
Maintenance Intervals. This checkout should be accomplished together
with the close-interval corrosion survey, the corrosion survey, the water tank calibration,
or when any inspection or survey indicates that problems with the rectifier may exist.
Visually check all rectifier components, shunt box components, safety
switches, circuit breakers, and other system power components.
Tighten all accessible connections and check temperature of all the
components listed in 4-5.2.1.
Using a dependable hand-held meter, measure the output voltage and
current, and calibrate the rectifier meters, if present.
For rectifiers with more than one circuit, measure the output voltage and
current for each circuit using a dependable hand-held meter, and calibrate the rectifier
meters, if present.
For rectifiers with potential voltmeters, using a dependable hand-held meter,
measure the potentials for each voltmeter, and calibrate that rectifier meter. Using a
known good reference electrode, measure the potential difference to the installed
permanent reference electrode by placing both electrodes together in the electrolyte
with CP current off. If the difference is more than 10 mV, replace the permanent
Calculate the cathodic protection system circuit resistance of each circuit by
dividing the rectifier DC voltage output of each circuit by the rectifier DC ampere output
for that circuit.
For all close-interval corrosion surveys, or if otherwise required, calculate the
rectifier efficiency. This also includes timing the revolutions of the kWh meter and
annotating the meter factor from the face of the kWh meter (refer to Chapter 5 for