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#72308 - 11/22/06 05:16 PM How can GRS be threaded when buried?  
Rich Thomas  Offline
Joined: Mar 2005
Posts: 48
Seattle, Washington, USA
An existing, buried, empty, 2-inch GRS conduit is to be used for a new application. One end stub-up remains as is, the other end will be relocated. The idea is to remove a portion of the conduit and replace it with a new portion that is routed to the new location.

What type of conduit connection would you recommend?

Could the existing conduit be threaded in place in the trench?

What method could be used to cut and thread it without removing it from the trench?


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#72309 - 11/22/06 05:36 PM Re: How can GRS be threaded when buried?  
iwire  Offline
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
You can hand thread 2" with a 2" NPT die, handle and oil supply.

Better than a manual handle would be a portable power threader.

This tool
[Linked Image]
combined with a 2" die and you will be done in under a minute.

Model 700 Power Drive

Just hang on tight...... [Linked Image]

[This message has been edited by iwire (edited 11-22-2006).]

Bob Badger
Construction & Maintenance Electrician

#72310 - 11/22/06 06:22 PM Re: How can GRS be threaded when buried?  
Celtic  Offline
Joined: Feb 2005
Posts: 361
Stick a 5' piece of 3/4 in the handle (the handle is threaded)...much easier to hold...but you may need someone to hold the button down.

~~ CELTIC ~~
...-= NJ =-...

#72311 - 11/22/06 07:00 PM Re: How can GRS be threaded when buried?  
Dnkldorf  Offline
Joined: Dec 2004
Posts: 1,064
nowhere usa
Don't they make a rigid compression coupling that is listed direct burial?

#72312 - 11/22/06 07:29 PM Re: How can GRS be threaded when buried?  
livetoride  Offline
Joined: Jan 2005
Posts: 109
san diego ca usa
A word of warning. I have had the threads on the next coupling back strip and break threading in place. If possable I would look for a joint to cut. Otherwise I would have a helper hold the pipe from spinning. Rod

#72313 - 11/22/06 07:53 PM Re: How can GRS be threaded when buried?  
e57  Offline
Joined: May 2003
Posts: 2,876
If you cant get/rent a threader like that, shoot for the ole' skool method and get a regular racheting die, and put your back into it.... (Or someone elses back) 3 forward - 2 back after you get it started, and use plenty of fluid.

Or if using a compression fitting - go for stainless tape tight with 20 mil, and if you really feel like you're cheating and your not.... Pour a little form of concrete. As for getting it tight enough - a trick I learned right here at ECN from Electure is to use a hammer drill with a chisle bit to work the edges of the fitting into getting tighter than possible with a wrench.

Mark Heller
"Well - I oughta....." -Jackie Gleason

#72314 - 11/22/06 09:04 PM Re: How can GRS be threaded when buried?  
walrus  Offline
Joined: Jul 2002
Posts: 680
Bangor Me. USA
iwire has the ticket, I thread pipe in the ground all the time with 700. 3 piece coupling and you're good to go. I wouldn't trust 3/4 pipe to hold a 700 back though, if the pipe breaks and it will on the thread the 700 might rip you a new one. If I couldn't hold it, I'd slip a piece of 2" over the handle.
Definitely hold the pipe you are threading with a wrench so as not to spin it. Livetoride is correct, you can break it at the next coupling.

#72315 - 11/22/06 09:11 PM Re: How can GRS be threaded when buried?  
iwire  Offline
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
The company I work for has a few of the rigid pony thread kits.

In the kit comes this support arm.

[Linked Image]

With this arm you don't even need a vice.

If you where to rent the threader you could ask if they have the arm to go with it.

Bob Badger
Construction & Maintenance Electrician

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