Volume-II of IV - GAIL

MECON LIMITED
Delhi
PROCESS & PIPING
DESIGN SECTION
TECHNICAL SPECIFICATION FOR
PERMANENT CATHODIC
PROTECTION SYSTEM
TECHNICAL SPECIFICATION NO. : MEC/TS/05/62/016B REV-1 Page 9 of 24
The anode shall be hollow type centrally connected or solid type end
connected, cable to anode joint shall be reliable and adequate for derigh life of
anode.
iv) Sheet steel anode canisters of adequate size shall be provided for each anode
of selected Anode canisters shall be filled with petroleum coke breeze with a
typical carbon content of 91.77%. String anode shall be used for days well
ground bed.
In case of deep well ground beds calcined fluid petroleum coke breeze with a
typical carbon content of 91.77% shall be provided in the well surrounding the
anodes.
v) Each shallow anode bed shall contain anodes with canisters positioned
horizontal or vertical in the soil with suitable backfill at appropriate depth with
respect to configuration horizontal or vertical.
vi) Layout of anode installation in anode bed shall be detailed out in drawings
showing anode installation details, anode grouping, anode wiring, anode cable
routing etc.
The deepwell anode ground bed details shall include the details of anodes,
deepwell casing, anode positioning, anode cable supporting, deepwell gas
venting, active, passive portions of ground bed etc.
vii) Anodes shall be supplied complete with tail cables which shall be long enough
for termination on their associated junction boxes without intermediate joints.
Exact lengths and termination details shall be indicated in construction
drawings by Contractor.
viii) Anode bed separation from pipeline shall be tested for interaction.
ix) Potential gradient around the anode bed shall be within safety requirements
and its effective boundary shall be defined and secured.
x) In case two parallel pipelines running in the same ROW. The anode ground
beds of respective pipelines shall be located on the respective sides of the
pipelines.
xi) The depth of deepwell anode ground bed shall be sufficient enough to reduce
anode influence on incidental structures within proposed location.
7.3 Anode Junction Box
i) Depending on the size and configuration of anode ground beds, one or more
anode junction boxes shall be provided at each ground bed.
All cable tails from individual anodes shall be terminated onto these anode
junction boxes which shall be further connected to anode cable coming from
CP station power source.
ii) Junction boxes shall have sheet steel enclosure of minimum 3 mm thickness
and hinged lockable shutters. They shall be weatherproof with degree of
protection IP-55. Junction boxes shall have anode bus and terminal plate with
adequate number of antiloosening type of identified terminals. Provision shall
be made for measurement and control of individual anode current by providing
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