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#72308 - 11/22/06 02:16 PM How can GRS be threaded when buried?
Rich Thomas Offline
Member
Registered: 03/09/05
Posts: 48
Loc: 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?

Rich
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#72309 - 11/22/06 02:36 PM Re: How can GRS be threaded when buried?
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4391
Loc: 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

combined with a 2" die and you will be done in under a minute.

Model 700 Power Drive

Just hang on tight......



[This message has been edited by iwire (edited 11-22-2006).]
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#72310 - 11/22/06 03:22 PM Re: How can GRS be threaded when buried?
Celtic Offline
Member
Registered: 02/26/05
Posts: 361
Loc: NJ
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.
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#72311 - 11/22/06 04:00 PM Re: How can GRS be threaded when buried?
Dnkldorf Offline
Member
Registered: 12/12/04
Posts: 1064
Loc: nowhere usa
Don't they make a rigid compression coupling that is listed direct burial?
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#72312 - 11/22/06 04:29 PM Re: How can GRS be threaded when buried?
livetoride Offline
Member
Registered: 01/11/05
Posts: 109
Loc: 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
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#72313 - 11/22/06 04:53 PM Re: How can GRS be threaded when buried?
e57 Offline
Member
Registered: 05/27/03
Posts: 2876
Loc: S.F.,CA USA
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.
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#72314 - 11/22/06 06:04 PM Re: How can GRS be threaded when buried?
walrus Offline
Member
Registered: 07/25/02
Posts: 680
Loc: 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.
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#72315 - 11/22/06 06:11 PM Re: How can GRS be threaded when buried?
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4391
Loc: 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.



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.
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Bob Badger
Construction & Maintenance Electrician
Massachusetts
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