chase nipple and electrical continuity

[smallfish]

Does the use of a chase nipple inserted from the inside of an enclosure through a knockout and threaded into a conduit body, provide electrical continuity when a metal raceway joins an enclosure through a conduit body in this manner?

Where can be found the UL listed use of a chase nipple?

Thanks

 

[LarryFine]

Interesting question. Calls for a 7/8" internally-toothed lock-washer, doesn't it?

I'd say it's okay if you remove paint.

 

[smallfish]

Calls for a 7/8" internally-toothed lock-washer, doesn't it?

Perhaps, or does being electrically continuus require a close nipple in lieu of the chase nipple, the short nipple with locknuts on either side of the enclosure wall?

The locknuts being heavy-type formed-steel locknuts the surface of which is serrated (as opposed to being flat or ribbed)? Info found in Soares book on Grounding and Bonding, page 134.

If this raceway connection to this enclosure fails to be electrically continuous, the equipment could lose its equipment grounding connection due to the fact that the raceway is the equipment grounding conductor means for an outside AC rooftop unit.

Does one use what you suggested, a 7/8 inch internally-toothed lockwasher?

 

[LarryFine]

Does one use what you suggested, a 7/8 inch internally-toothed lockwasher?

Maybe the chase nipple has enough thread for a locknut and the conduit body. Another option is an EGC from the enclosure to the first J-box or other access point where you can establish a bond to the conduit system.

 

[Howard Burger]

sealing locknut too?

sealing locknut too?

Would you not need two locknuts, one toothed for the grounding continuity, and one sealing locknut for weather tightness? Which would probably rule out the chase nipple in favor of the close nipple?

(The Soares refrence is page 138.)

 

[renosteinke]

Depends on which chase nipple ...

Chase nipples come in various lengths, and it's absolutely possible for a particular nipple to 'bottom out' in a fitting and not provide reliable contact.

It's also quite possible for the threads on the nipple to be the wrong threads for the conduit body, so it depends on you using the right body as well.

Guys, UL cannot possibly evaluate every possible combination of every component that exists - then proceed to list those on the lable. Or in the White book. Or anywhere else, for that matter. It simply can't be done.

Instead, there is a supposition that the work will be done in a sensible manner by folks who know what they're doing. You can't make it absolutely idiot-proof; they keep developing better idiots.

As to the specific question ... how does UL test? Well, it's a pretty straightforward test, where a lab tech simply screws two things together and applied a 'hi-pot' (or 'dielectric withstand) test. I can tell you, from personal experience, that it's simply amazing how poor of a connection will pass the test. Trust me - our 'trade practices' are WAY above and beyond the minimum required to pass the test.

That's why the code has a requirement that parts be installed in a 'workmanlike' manner.

 

[bullheimer]

exactly, and my2c's is that there had to be at least one locknut in this sitiation somehow or nuther. and if you are in concentric ko's then maybe even a grounding locknut. easier to run a ground wire sometimes. this is illegal i think, but last time i did this i drilled a hole in the conduit body, threaded a 10-32 into it and ran a ground to the screw. might be hokey, might be illegal, but it dam sure grounded the raceway.

 

[LarryFine]

this is illegal i think, but last time i did this i drilled a hole in the conduit body, threaded a 10-32 into it and ran a ground to the screw. might be hokey, might be illegal, but it dam sure grounded the raceway.

Don't tell anyone I said this, but, I like it.