3 Piece Coupling..

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Coppersmith said:
Yes, and they are awesome for running rigid with lots of bends. Of course, I've never had to pay for them.
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Thanks. So they are for when you can't spin the pipe on. Why would bends make it difficult to spin the pipe on? Would it make a difference if it was field bends or pre-fab elbows? Thanks
 
We call them:
Three piece suit
Oswego coupling
Erickson
Here is when you find out how good your men are.
 
sameguy said:
We call them:
Three piece suit
Oswego coupling
Erickson
Here is when you find out how good your men are.
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awwww...LMAO now I feel bad and take back what I said. Honestly sorry. Anyway, I've never been in the field and haven't come across or gotten any feedback on these being used often. So I'm not(wasn't) sure in what circumstances they would needed. Or when the pipe couldn't be spun on. Thanks....I'll give one to myself...:slaphead:.....from you:)
 
LarryFine said:
Minimizing 3-piece coupling use is an art not unlike a major Wiremold installation.
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And how do you minimize their use? First I'd like to clearly understand in what situations they have to be used. I have some long horizontal runs of 4" RGS that have pull boxes in between and bends.

Each run is about 300' with (4) horizontal 90's and 2 pull boxes.
 
I did a job where we had four parallel runs of 4" rigid zig-zagging throughout an existing hospital many hundreds of feet. There were a lot of tight spots where you just could not spin the bent pipe on. That's where they are needed. On most jobs their use is minimized since they are expensive.

We also used them for all the other places where they weren't needed like straight runs. It made doing the work a lot easier since there was no pipe spinning. Just attach the Erickson, slide the pipe together, and tighten the coupling. I don't know why they wanted us to use those everywhere, but I didn't object. Guess the job had a lot of money in it.
 
We ought to be able to put LH threads on pipe when we want. Then use a coupling with both a LH and RH thread and it pulls the pipes together, only by turning the coupling. I've seen plumbers do this often, like in sprinkler line fitting.


No expensive fittings required, but you do need the ability to LH thread a pipe end.
 
They do make rigid compression couplings and connectors also. I use them all the time since I don't have threading capability.
 
mstrlucky74 said:
And how do you minimize their use? First I'd like to clearly understand in what situations they have to be used. I have some long horizontal runs of 4" RGS that have pull boxes in between and bends.

Each run is about 300' with (4) horizontal 90's and 2 pull boxes.
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A simple example of avoiding one is where you plan your run and installation so you only need to spin the short leg of an L instead of the long leg. Or, you have to run a conduit through a penetration into a threaded fitting. You have to be able to spin either the fitting or the conduit. Or, you're running around inside corners instead of outside corners. Sometimes, you install an assembly.

Not too long ago, I ran RGS to a shed to minimize burial depth. A 3' stub-up into the floor of the shed at one end, and a 2' stub-up into a threaded LB to a nipple through the house foundation. I put the shed stub in first by lifting the conduit up over 45 degrees. Then threaded two lengths to that one, and the LB stub last, laid it in the trench, then threaded the nipple from inside the crawl space.

It would have been impossible to do had I started at the house with the nipple and the LB first. By the way, I put a J-box inside the crawl space to change from THWN to NM to run to the panel. In the shed, I put another J-box near the floor, and likewise changed to NM to hit the sub-panel. And yes, I installed an EGC in the conduit, figuring that it won't be there forever. (And only one ground rod.)
 
For large RMC runs Erickson couplings are terrible, half of the time the pieces don't thread all the way on to the manufactured threads. I would use a split coupling instead.
 
Coppersmith said:
They do make rigid compression couplings and connectors also. I use them all the time since I don't have threading capability.
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I have just what you need sitting in a garage, in N.Y., Rigid 300, power pony, 2 hog heads, universal bar, oiler, take a run up Ill make a deal; big core drill, couple tri stands. :) :)
 
Sometimes to avoid a union one has to assemble pieces away from where they are to be installed just because there is room to spin them there.

Sometimes you carefully select a place to put a regular coupling instead of at the naturally occurring end of a stick of conduit to help facilitate assembly. Now cutting and threading for this may cost more in labor than using the union in some cases, but at same time if you only have limited number of unions on hand you won't carelessly put them where you don't have to.
 
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