UFC 3-570-06
JANUARY 31 2003
4-8.1
Procedure
4-8.1.1
Measure the potential of the structure with the reference electrode located
directly over the structure, adjacent to an anode (structure-to-earth, DC volts).
4-8.1.2
Measure the potential of the structure with the reference electrode located
directly over the structure, midway between anodes (remote structure-to-earth, DC
volts). In this case, remote is as far as possible from the anodes, directly over the
protected structure.
4-8.1.3
Disconnect the anode lead from the structure and measure potential of the
anode with the reference electrode located directly over the anode (anode-to-earth, DC
volts).
4-8.1.4
Measure structure-to-anode current (anode output current, mA).
4-8.1.5
Compare measurements to those previously taken at the same location.
Loss of anode-to-earth potential indicates a failed anode or failed anode lead. Loss of
anode output current with stable anode-to-earth potential indicates consumption of the
anode and pending failure. Loss of structure-to-earth potential with stable anode-to-
earth potential and anode output current indicates loss of isolation.
4-9
check of two metallic structures connected with some type of semi-conductor or resistor,
to ensure that the structures affected by the bond are maintained at proper levels and
interference is mitigated. This bond may include reverse current switches, diodes,
resistors, or other protective devices whose failures would jeopardize structure
protection. These bonds may be between different sections of a protected structure, or
may be between a protected structure and any other metallic structure (unprotected or
protected with a different cathodic protection system). This is a non-interrupted check
and the potential measurements should be compared to previous ON cycle potential
measurements taken at the same locations. The locations for the potential
measurements and meter connections must be the same and the operational status of
any cathodic protection systems must be known.
4-9.1
Maintenance Interval. The recommended period for conducting the
resistance bond check is within 60 days of the last check or immediately following
failure of the CP system protecting either (or both) sides of the bond (unless immediate
repair of the failure is possible). More frequent checks may be required by public law or
local regulations.
4-9.2
Minimum Requirements
4-9.2.1
Measure rectifier DC voltage ampere output of the cathodic protection
4-13
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