Cathodic protection isolation & EGC

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Dsg319

Dsg319

Senior Member
Location
West Virginia
Occupation
Wv Master “lectrician”
wondering if anybody has any insight or knows about this. From time to time we will have to work with MOV (motor operated valves) that are on and connected to a pipeline. Which has cathodic protection, and if we’re using all metal (robroy) conduit we will use a isolation coupling between the pipeline valve and our metal conduit.

I understand the concept of this but don’t understand how it works when you also have an Equipment Grounding Conductor in the same raceway going back to the electrical equipment and attached to the valve chassis. Is there also something isolating the EGC from having dc current from traveling back on electrical rack and equipment. Any ideas?
 
Hydraulic actuators on pipeline valves are available with an insulating kit that isolates the actuator from the piping. I do not know if MOV vendors offer a similar kit.
 
nhee2 said:
Hydraulic actuators on pipeline valves are available with an insulating kit that isolates the actuator from the piping. I do not know if MOV vendors offer a similar kit.
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That makes sense. Currently also working on a small valve set that is gas operated. (Actuator and open and close solenoids valves and limit switches),

Although these jobs spec out pvc underground with ridgid risers so no worry with the raceway(isolation), but the inspector has told us not to pull an EGC from the valve set to the rtu where are inputs and outputs are to operate the valve.For the simple reason of the cathodic protection on the pipeline. But In my mind idk if this is correct but than again can’t think of a way for it to work without having cathodic protection current from the pipeline travel on EGC to electrical rack and grounding.
 
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