250.64(B) - FMC NOT for protection

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dana1028

Senior Member
I know 250.64(B) does not allow the use of FMC for protection. But - what about running the GEC in FMC when the purpose is not for protection.
Scenario: Routing of the PV circuit conductors is through an attic after transitioning from EMT on the roof, then snaking through a stud bay to the service equipment; the GEC runs with the circuit conductors because it is also playing the dual role of the EGC.

Under this scenario the GEC does not need protection - the location and routing of the GEC is plenty safe enough [BTW - the GEC is a #6 stranded].

My understanding of 250.64(B) is that the various raceways listed in that section are selected for the purpose of 'protecting' the GEC; Soares stresses this point [i.e. the purpose of these selected raceways is for protection].

So I ask the forum - when the function of a raceway is not to protect the GEC, are we still limited to using only those listed in 250.64(B)?
 

Smart $

Esteemed Member
Location
Ohio
Perhaps to satisfy 690.31(E).
Hmmm... more likely 690.47(C)(3)...

(3) Combined Direct-Current Grounding Electrode Conductor
and Alternating-Current Equipment Grounding
Conductor.
An unspliced, or irreversibly spliced, combined
grounding conductor shall be run from the marked dc grounding
electrode conductor connection point along with the ac
circuit conductors to the grounding busbar in the associated ac
equipment.
This combined grounding conductor shall be the
larger of the sizes specified by 250.122 or 250.166 and shall
be installed in accordance with 250.64(E).

...the GEC runs with the circuit conductors because it is also playing the dual role of the EGC. ...

AFAIK, and otherwise ignoring 690.47 for this statement, there is no restriction from running a GEC within circuit conductors' raceway... which is what it is and not protecting only the GEC against physical damage. In the OP's case with a combo EGC/GEC, it is actually required.
 
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GoldDigger

Moderator
Staff member
Location
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Hmmm... more likely 690.47(C)(3)...





AFAIK, and otherwise ignoring 690.47 for this statement, there is no restriction from running a GEC within circuit conductors' raceway... which is what it is and not protecting only the GEC against physical damage. In the OP's case with a combo EGC/GEC, it is actually required.
Also note that when the raceway is ferrous, it is necessary to bond the GEC at both ends of the raceway. That is not necessary for the EGC alone, but in the case of a combo EGC/GEC, the bonds are are necessary.
 

Smart $

Esteemed Member
Location
Ohio
Also note that when the raceway is ferrous, it is necessary to bond the GEC at both ends of the raceway. That is not necessary for the EGC alone, but in the case of a combo EGC/GEC, the bonds are are necessary.
...which is covered by the second sentence of 690.47(C)(3) stipulating "...shall be installed in accordance with 250.64(E)."
 
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