GEC run with feeders in conduit

[lfloyd]

I have an installation where they have run the water and gas piping bonding conductor from the building to the service outside in the same conduit as the feeder conductors to a panel.
I have not seen a grounding electrode condutor run with feeder conductors before.
Is this allowed?

 

[Dennis Alwon]

I don't believe there is a rule against it however if it is metallic piping then the appropriate bonding must be done when a grounding electrode conductor is installed.

 

[mwm1752]

You mentioned feeder -- sounds like a EGC that ties to the metal frame of the structure panel.

Did you mean to say -- have an exterior service that sends a feeder to the structure which bonds to the structure electrode system? Your description of the routing of power from structure to transformer has me a bit confused.

 

[lfloyd]

They have a service outside the building and needed to run the water and gas piping bonds to the service and ran them in the same conduit feeding a sub panel in the building. The water is part of the electrode system. I have never seen a grounding electrode conductor run with any other conductors.
I guess it's not wrong just new to me.

 

[GoldDigger]

They have a service outside the building and needed to run the water and gas piping bonds to the service and ran them in the same conduit feeding a sub panel in the building. The water is part of the electrode system. I have never seen a grounding electrode conductor run with any other conductors.
I guess it's not wrong just new to me.

A GEC or EGC or miscellaneous bonding jumper cannot be run inside a ferromagnetic (steel) conduit unless it is also bonded to that conduit using listed equipment at both ends.
The reason is that the conduit causes that section of GEC to act like a choke (series inductor) and raises the impedance of the conductor for lightning-induced surges and other high frequency fault currents. This applies whether there are other conductors in the conduit or not. This may be the main reason that you have not seen this kind of installation before.
Unless the raceway in question is aluminum or PVC, or the necessary bonding was done (not very likely) then it is not code compliant on that basis alone.

 

[electrofelon]

A GEC or EGC or miscellaneous bonding jumper cannot be run inside a ferromagnetic (steel) conduit unless it is also bonded to that conduit using listed equipment at both ends.
The reason is that the conduit causes that section of GEC to act like a choke (series inductor) and raises the impedance of the conductor for lightning-induced surges and other high frequency fault currents. This applies whether there are other conductors in the conduit or not. This may be the main reason that you have not seen this kind of installation before.
Unless the raceway in question is aluminum or PVC, or the necessary bonding was done (not very likely) then it is not code compliant on that basis alone.

Can you give a code reference for that? I thought only the GEC was specifically prohibited from running in a metallic raceway without bonding on each end?

 

[GoldDigger]

Can you give a code reference for that? I thought only the GEC was specifically prohibited from running in a metallic raceway without bonding on each end?

There is no code reference for that. My reference to an EGC was intended to call attention to any possible situation in which ONLY the EGC and not all of the associated circuit conductors that would be contributing the fault current was run in a ferrous raceway.
Fortunately that is not likely to happen. And is probably also one of the reasons that for paralleled circuit conductors spread across multiple raceways each raceway must contain (or itself be) a full sized EGC. Otherwise the fault current from a wire break in one of the raceways would end up returning via the EGC in a different raceway, with the corresponding choke effect.

An interesting sidelight (digressions, digressions) is that if the raceway itself is the EGC, there will be no choke effect on the fault current returning via the raceway, but there will be a choke effect on the fault current itself running out through the internal conductors. Very neat and a reduction in available incident energy and short circuit current that may not always be considered, I suspect.

Also, to keep things clear for the future, the distinction is a ferrous raceway, not just any metallic raceway such as aluminum.

 

[A/A Fuel GTX]

They have a service outside the building and needed to run the water and gas piping bonds to the service and ran them in the same conduit feeding a sub panel in the building. The water is part of the electrode system. I have never seen a grounding electrode conductor run with any other conductors.
I guess it's not wrong just new to me.

The service outside I assume is mounted to a structure? If so, then all that would be needed would be a couple of ground rods since no other electrodes are available. Then, the sub panel where the feeders are terminated would be the place to land the GEC from the available electrodes in the building the feeder is serving.