Can this be done-combo GEC and EGC?

D

Dale001289

Senior Member
Location
Georgia
We have a large bare copper EGC (500kCMIL) routed in a power cable tray for paralleled 350kCMIL feeders. There are three small dry type transformers (9-25kVA) solidly grounded installed along the same path as the cable tray.
The contractor wants to tie the transformer GECs to this EGC for sake of convenience rather than route the GECs directly to the grounding electrode system, (ground rods). Is this permissible?
 
My understanding is that if the EGC follows all of the relevant rules for a GEC (size, bonding to enclosing raceways to prevent choke effects, 'irreversible splicing' (if that hasn't changed yet), etc) then a single conductor can serve as both EGC and GEC
 
Dale001289 said:
Don, you don’t see any issues with this conceptually right?
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No, I have submitted PIs to specifically permit that, but they have been rejected. The only issue would be if you leave the tray using a ferrous raceway, and then you would have to bond the ECG/GEC to each end of the ferrous raceway.
The combination conductor will have to be the larger of what is required for the EGC or the GEC. Some might see that conductor as a common GEC, as provided for in 250.30(A)(60(a)(1) and require the conductor size to be 3/0.
 
don_resqcapt19 said:
No, I have submitted PIs to specifically permit that, but they have been rejected. The only issue would be if you leave the tray using a ferrous raceway, and then you would have to bond the ECG/GEC to each end of the ferrous raceway.
The combination conductor will have to be the larger of what is required for the EGC or the GEC. Some might see that conductor as a common GEC, as provided for in 250.30(A)(60(a)(1) and require the conductor size to be 3/0.
Click to expand...
Thanks for this feedback
 
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