Running Thread

[magoo66]

I was taught as an apprentice that running thread or all-thread was not allowed for service entrance conduit, can't seem to find where it is specifically prohibited in the code. Is it a listing/labeling issue, or just a shop/local thing?

 

[tkb]

ARTICLE 342 Intermediate Metal Conduit: Type IMC
342.42 Couplings and Connectors.
(B) Running Threads. Running threads shall not be used on conduit for connection at couplings.

ARTICLE 344 Rigid Metal Conduit: Type RMC
344.42 Couplings and Connectors.
(B) Running Threads. Running threads shall not be used on conduit for connection at couplings.

 

[magoo66]

Thanks Tim, yes I saw the coupling rule, but about 15 years ago the local AHJ made me replace a 6" piece of 2" running thread that I had used on a service upgrade between the exterior 200a meter pan and interior panel board. No couplings, just 4 locknuts and 2 bond bushings. Had to replace it a grc nipple or pvc.

 

[cadpoint]

Well, what did you put back in?

I learned somthing yesterday!

I was frankly thinking that a little bad math was involved, either conduit was just short of the panel one inserts a coupling that mates flush to the panel then
an all thread(chase nipple)...

I reckon

 

[LarryFine]

... about 15 years ago the local AHJ made me replace a 6" piece of 2" running thread that I had used on a service upgrade between the exterior 200a meter pan and interior panel board. No couplings, just 4 locknuts and 2 bond bushings. Had to replace it a grc nipple or pvc.

In my opinion, that was a wrong call. I've done it for back-to-backs, too, as well as through studs between panels.

 

[kwired]

...just 4 locknuts and 2 bond bushings...

That is not running threads at a coupling and should not have been rejected.

 

[magoo66]

Thanks guys, another "that's the way we've always done it" put to rest.