Parallel Cable Tray Feeders & Grounding

[augie47]

When using cable tray if an E/C elects to run multi-conductor TC cables in parallel but fails to
install TC cables with equipment grounds adequate for the overcurrent device, is it permissible to:
(a) use the Cable Tray as the grounding conductor assuming it is listed as such and
properly sized.
(b) install a properly sized single equipment grounding conductor in the tray and use it for
grounding.

If either (a) or (b) is employed, what is the proper way to handle the original undersized ECG in the TC.

 

[Smart $]

IMO (and probably controversial to some others we'll hear from), either way is fine... or both. Pretty much same with cable EGC's either land or isolate. Ultimately, landing them is safer.

 

[don_resqcapt19]

From a code standpoint, (a) is permitted only if you don't land the internal EGCs. I don't think the code permits (b) where the wiring method is a cable.

From a real world point of view, I think either will do the job and see no reason not to connect the internal EGCs.

 

[iwire]

(and probably controversial to some others we'll hear from),

:roll:

When using cable tray if an E/C elects to run multi-conductor TC cables in parallel but fails to
install TC cables with equipment grounds adequate for the overcurrent device, is it permissible to:
(a) use the Cable Tray as the grounding conductor assuming it is listed as such and
properly sized.
(b) install a properly sized single equipment grounding conductor in the tray and use it for
grounding.

If either (a) or (b) is employed, what is the proper way to handle the original undersized ECG in the TC.

Gus IMO it depends on if you feel 2014 300.3(B)(1) or 300.3(B)(3) applies.

Take a look at this post of Don's http://forums.mikeholt.com/showthread.php?t=170162&p=1654713#post1654713 and make your own call on how the CMP feels.