Effectively Bonded

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Rocky58

Member
Location
Lexington, KY
Would GRC / IMC / EMT conduit installed using strut support to steel columns that have been intentionally grounded to a 1/0 ground grid be considered effectively bonded / grounded to the structure. The strut may be drilled and bolted to the columns, window clamped or beam clamped and the use of strut straps to secure the conduit to the supports.
 

Smart $

Esteemed Member
Location
Ohio
Would GRC / IMC / EMT conduit installed using strut support to steel columns that have been intentionally grounded to a 1/0 ground grid be considered effectively bonded / grounded to the structure. The strut may be drilled and bolted to the columns, window clamped or beam clamped and the use of strut straps to secure the conduit to the supports.
No offense intended, but it sounds like you are not divulging the entire story and trying to get around required bonding.

However, the answer to your query as stated is yes.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
While the conduit may be effectively bonded by that physical connection, that bonding would not satisfy the requirements of the NEC.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
While the conduit may be effectively bonded by that physical connection, that bonding would not satisfy the requirements of the NEC.

I agree. The conduits may be bonded but 250.86 requires they be connected to the equipment grounding conductor and 250.136 provides that the structural metal frame of a building can not be used as the required equipment grounding conductor,.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Would GRC / IMC / EMT conduit installed using strut support to steel columns that have been intentionally grounded to a 1/0 ground grid be considered effectively bonded / grounded to the structure. The strut may be drilled and bolted to the columns, window clamped or beam clamped and the use of strut straps to secure the conduit to the supports.

what code requirement is there to bond the conduit to the structure?
 

Rocky58

Member
Location
Lexington, KY
Rocky58

Rocky58

All power conduits have the required NEC equipment grounding conductor and is terminated correctly. The control device conduits do not have a ground wire and the majority of these are operating at 120v. The assistant electrical engineer is suggesting that the low volt sub bond his conduit to the structure thinking that this is a fix. I cannot find anything that would even remotely make this a code requirement or an answer to not having a ground wire installed in the conduit. My conversation with the low volt sub was that because he is at 120v there is no exception that I could find which would allow his current installation.
 

Smart $

Esteemed Member
Location
Ohio
A grounding wire is not required in metal raceways as long as the raceways are bonded as required.
 

Rocky58

Member
Location
Lexington, KY
Rocky58

Rocky58

what code requirement is there to bond the conduit to the structure?
We have an assistant electrical engineer 2 or 3 years out of school on his first project listening to so-called plant experts and trying to cover his butt. We also have a client who builds power plants in the UK trying to build and operate a biomass fuel plant who hasn't hired experienced plant engineers. You know, just another day in the electrical trade where everyone is an expert. I can't find anything NEC wise that requires the conduit to be bonded to the structure and I have grounds in all of my conduits and terminated as required per termination point.
 

Smart $

Esteemed Member
Location
Ohio
There are times you forget the forest because of the trees. His installation does have underground PVC conduit in the run.
Even with control* an EGC is required to be run with circuit conductors. No amount or type of bonding on either side of the PVC run can make the installation compliant if no EGC is run with the circuit conductors.

*...excepting "Class" and communications control circuits.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Even with control* an EGC is required to be run with circuit conductors. No amount or type of bonding on either side of the PVC run can make the installation compliant if no EGC is run with the circuit conductors.

*...excepting "Class" and communications control circuits.

bingo!
 
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