If i'm running multiple circuits on cable tray (may be not listed to be used as EGC) & i'm going to install conduits to fit all drops down <9 ft from cable tray to served panel, in case of having two or more conduits for one circuit does it need a separate EGC for each single conduit along the line from the upstream to downstream or one EGC is OK since it's just max 9 ft.
300.3(B)
- Thread starter m sleem
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arcsnsparks98
Senior Member
- Location
- Jackson, TN USA
Each conduit that is part of a parallel feed needs to be symmetrical so you would need an EGC in each one.
Just an example if the total run is 300ft while the drop is 9ft that needs a complete EGC along 300ft ?!!
arcsnsparks98
Senior Member
- Location
- Jackson, TN USA
One EGC along 300' in the cable tray (assuming the cable tray cannot be used as the EGC) then split into two or more smaller EGCs going through the conduits. My codebook isnt in front of me so I cant cite references but this should be an acceptable install.
250.122(f) doesn't allow to split into smaller conductors, each EGC shall be full size.
- Location
- Massachusetts
Exactly and there is no 'short distance' exception.
mjc763
Member
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- Minneapolis Minnesota
Could he run one full size egc in the cable tray and then branch off into two full size egc, one fire each pipe? That way you don't have to run two 300' runs of the same wire. Haven't worked with cable tray that much so idk about splicing in it.
I wish if that meet NEC requirements, that's really good solution.
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- Massachusetts
For sure.
arcsnsparks98
Senior Member
- Location
- Jackson, TN USA
Well, I just learned something new. Apparently 250.122(f ) was revised for the '11 code. Glad I was made aware of that. 
- Location
- Illinois
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- retired electrician
Are the circuits in the cable tray installed using single conductors or using tray cable? The answer is different based on the wring method used in the tray.
All cables are multicore cables, i wish if my answer replies your question.
- Location
- Illinois
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- retired electrician
Then each cable of a parallel set must have an EGC that is sized based on the the rating of the overcurrent protective device that feeds the parallel cables.
- Location
- Placerville, CA, USA
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- Retired PV System Designer
Which may be hard to find in multi-core cables.
If the required EGC is undersized compared to the circuit conductors, you might be able to make it work with cable that has a full sized EGC.
Would that mean if i have three multicore cables laid on the same cable tray that requires three EGC full sized?
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- Location
- Placerville, CA, USA
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- Retired PV System Designer
Only if they form a set of parallel conductors for one circuit. Otherwise each cable only needs an appropriately sized EGC for its own circuit.
I Wish If I?m Not Mistaken, I understand from replies that the top one from the below sketch is the right one, isn't?
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- Location
- Illinois
- Occupation
- retired electrician
It would be my opinion that neither one is code compliant. If you have a cable assembly the EGC must be part of that cable assembly. It cannot be run external.
If i don't have such cable what could do?
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