Insulated ground ring

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kenaslan

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Billings MT
Does anyone know of any reason that an underground ground ring would be insulated? It seems to me that an insulated ground wire defeats the purpose.

Ken
 
kenaslan said:
It seems to me that an insulated ground wire defeats the purpose.
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Given that "contact with planet Earth" is the purpose of a grounding electrode system, I would have to agree with you. Did you really encounter this, either as in design document (plans or specs) or in the field? That would be extraordinary.
 
It is in a specification for the grounding system of a gas pipeline, I now have found out they want to use galv cable instead of copper. I was told that copper oxidizes. Hmm after 30+ years in the industry I must have been doing it wrong all this time, LOL
 
LarryFine said:
They've never heard of zinc oxide?
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Or tined copper. I remember a job that specified tined and the estimator figured standard cu.We were behind before we even started.
 
kenaslan said:
It is in a specification for the grounding system of a gas pipeline, I now have found out they want to use galv cable instead of copper. I was told that copper oxidizes. Hmm after 30+ years in the industry I must have been doing it wrong all this time, LOL
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Their concern is with corrosion of the pipe. In galvanic corrosion, steel will sacrifice itself to the copper in a grounding system. If the grounding system is galvanized steel, this is not a problem.

The only way the insulated cable makes sense is if it connects ground rods that are at a distance from the pipeline such that galvanized corrosion from the rods will not be a problem and the rods alone provide an adequate ground. The conductors will not add anything to the effectiveness of the grounding system and will only connect the rods together. But then why use galvanized cable?
 
In our gas pipeline plant and facilities, the ground loop conductors are insulated. My understanding is that it is to reduce the effect of the cathodic protection system (that protects the underground pipe) on the ground conductors.
 
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