effective ground fault path 2008 nec

[grumpy11]

im doing a service and im installing emt conduit from load side of service switch to a panel.

my intension is to run emt with set screw connectors steel both connectors and couplings.

install bonding locknuts at both ends.and not pull an egc in the conduit.

engineer says {now we both put this design together so its a friendly debate} that if we use set screw connectors we have to install a egc because set screw does not make an effective ground fault path. but if we use compression connectors and couplings we dont have to install an egc.
but still have to bond conduit to enclosures with bonding locknut .

 

[hurk27]

Since this is from the load side of the service disconnect these are feeders, and depending upon the voltage the NEC allows set screw connectors as a means of grounding, 250.118 clearly allows EMT as a fault path and even grounding bushings will not be required depending upon the system voltage.

 

[grumpy11]

the voltage is 120/208 3 phase 4 wire.

 

[don_resqcapt19]

All of the listed EMT connectors and couplings are suitable for grounding. It is my opinon, one that few engineers agree with, that the set screw type provides a better grounding connection than the compression type.

 

[grumpy11]

i agree but is there someplace within the code thats says that.

 

[dkidd]

From the UL White Book

Electrical Metallic Tubing Fittings (FKAV)
Grounding ? These fittings are considered suitable for grounding for
use in circuits over and under 250 V and where installed in accordance
with ANSI/NFPA 70, ??National Electrical Code.??

If they are UL listed, they are approved for grounding.

 

[grumpy11]

i agree with all of you i have the white book at home i will look it up .

any more comment are welcomed

 

[infinity]

i agree with all of you i have the white book at home i will look it up .

any more comment are welcomed

Stop listening to engineers when you know that you're right. Sorry just couldn't resist. :lol:

 

[Ponchik]

....... set screw type provides a better grounding connection than the compression type.

agree.


As said earlier, your installation sounds fine. I don't think you even need the bonding locknuts.

No disrespect intended, but sometimes you have to watch out for engineers.

 

[ryan_618]

I also agree. The raceway is a better EGC than the copper conductor. your'e engineer is up in the night. You should direct him to this thread.

 

[ActionDave]

All of the listed EMT connectors and couplings are suitable for grounding. It is my opinon, one that few engineers agree with, that the set screw type provides a better grounding connection than the compression type.

I agree. I agree again and again. I wonder what it would take to convince the engineers?

 

[iceworm]

I agree. I agree again and again. I wonder what it would take to convince the engineers?

Instead of just lip service, follow MIL-TFD-41.

ice