Need a little help

[Tulsa Electrician]

Oklahoma has adopted the 2017 NEC, Tulsa is still on 2104 NEC. In preparation for an code update to 2107 I have been reading through the New parts of 2017. I ran across one I am just not clear on.
"use non-threaded fittings"
How does this apply to an Installation method and can some one give me a real world example. I'm having a hard time visualizing the situation. I do a lot of roof installations and I want to be up to speed.


New for 2017
"440.9 Grounding and Bonding. Where multimotor and
combination-load equipment is installed outdoors on a roof, an
equipment grounding conductor of the wire type shall be
installed in outdoor portions of metallic raceway systems that
use non-threaded fittings."

About all I can come up with is an EMT to FMC one piece fitting.

This is why I follow hhsting post. He always looking for 2107 ansawers.

 

[synchro]

I interpret it this way: If you're using RMC or IMC with threaded fittings for these types of installations, then you don't need a wire-type EGC. Otherwise, you will need to have a wire-type EGC.

 

[Tulsa Electrician]

OK I think I get it.
So if i run outdoor on roof using EMT ( EMT as an example) and compression fitting than a wire type EGC Shall be used. We do roof work where this is common place. As a rule we run a wire type EGC anyway. What I do find interesting is this is one time EMT can not be used as an EGC.
I will give an example we have a roof top Panel and run feeders to RTU,s using EMT and rain tight compression fitting. A wire type EGC shall be installed.
Comment: I can understand why based on how many times the roofers/ others have damaged the raceways connection(s) using compression fitting.

Thank you
If my comment is correct I will be sure to pass this on to the men.
I'm going back to 250.118 and make note in book by 250.118 (4) * see 440.9 Roof

 

[infinity]

If it's a threaded raceway it cannot easily pull apart at the fitting. Something like EMT or RMC with threadless fittings would require much less force to separate the raceway at a fitting that had no threads holding it together. On a roof raceways are subject to all sorts of stress and potential damage from people walking on them.

 

[Tulsa Electrician]

Thank you,
Also made note on 358.60
Laughed at 358.100
Never seen it or heard of it.
Seen it with factory set screw coupling.
Any one have a pic to share of factory threaded integral coupling send it my way.

Again thanks for helping me clear it up in my head. I was told once to never read past what you don't understand.