installing rigid

[pwrseeker]

My brief history, Navy trained plant electrician, worked 2 years with the
railroad troubleshooting electric mtrs and ckts. Now doing industrial work requiring some construction. Very little experience with rigid pipes. I know this may seem easy to many but I'm running a 1" rigid line to a generator. Conduit strapped on wall as I come around corner w/factory sweep and another full length then another sweep to raceway. My problem is how do I install the 2nd sweep. I don't have room to tighten sweep on the coupling, wall is in the way. I tried loosening the previous straps but still don't have the play. It would not like to dissamble most of my run to install a sweep. I also know I can use an errickson coupling but I know it can be done using regular coupling. I'm willing to learn ...anyone???

 

[cadpoint]

Order ahead

Order ahead

Order a threadless coupling, it acts like a Compression Emt Coupling but for ridge (w/ no threads even) but its not a thread coupling, but compression for ridge. If thats an erickson coupling ? so be it ...

You can't work that sweep in, your ain't working !

 

[celtic]

I'll take it back as far as I neccessary to spin a 90? on ....sometimes, you have work backwards....when running RMC, you MUST have a plan.

I will avoid using an erickson, union, 3-piece coupling (whatever you want to call it) as much as possible.

EDIT TO ADD:
No threadless either!

 

[Luketrician]

I'll take it back as far as I neccessary to spin a 90? on ....sometimes, you have work backwards....when running RMC, you MUST have a plan.

I will avoid using an erickson, union, 3-piece coupling (whatever you want to call it) as much as possible.

EDIT TO ADD:
No threadless either!

I usually call em' apprentice couplings

I hear ya Celtic, runnin rigid is like playin pool. Always gotta think about the next angle before you get past the first.

 

[DAWGS]

Make sure your 90 is stubed as short as you can then but ends up together and unscrew coupling from one conduit to other so it is half and half (this will make it easier to bow out and spin without having to start threads). Unstrap as far back as needed to get room to spin. If this doesnt work, install and LB or LL or LL fitting.

 

[don_resqcapt19]

If this doesnt work, install and LB or LL or LL fitting.

If the total bends will permit the wire to be pulled, I would always use a union before I would install a LB or other conduit body.
As far as using unions, it is often more cost effective than the work that is sometimes required to avoid the use of one. They have their place and if I get an electrician that says they should never be used, he/she goes back to the hall as that attitude will cost me too much money. Of course an electrican that wants to use a union at every bend will also go back to the hall. Where I am at, we will often make changes, after a year or two, that will require the removal of conduit, so as a result, I only permit the use of short 90's and almost never more than two bends between couplings. (I count an offset as one bend) The conduit removes and installs easier and there is less scrap with this method.
Don

 

[celtic]

I usually call em' apprentice couplings

I hear ya Celtic, runnin rigid is like playin pool. Always gotta think about the next angle before you get past the first.

LOL ...apprentice couplings.


Pool or chess are the analogies I use ....

 

[pwrseeker]

Thanks for the advice. I agree on not using compression fittings. I've seen similiar work done with the fittings completely threaded so I know it's possible I just didn't know how far back unstrapping I'd have to go to get it right.

 

[Nick]

I union circles we jokingly call them local (insert local union # of choice) couplings.
It is a challenge to see how good you are at running pipe by not using any. Sometimes you just have to. I have been on Sewage plant jobs that prohibit their use in the spec. I am bidding a job right now that calls out a concrete MV ductbank to be run in 4" rigid with 10 and 30 foot radius seeps and calls out in bold letters do not use 3 piece or thread-less couplings under ground. How you put that together 6ft deep in a trench around shoring is a mystery to me.

 

[celtic]

How you put that together 6ft deep in a trench around shoring is a mystery to me.

Think outside the box...or in this case, the trench ....and have some saw horses handy for the men.

 

[e57]

Think outside the box...or in this case, the trench ....and have some saw horses handy for the men.

Reverse thread would great in this situation - finding some unthreaded couplings and some dies might be a problem.

Otherwise I have carried whole runs into the trench complete before too - lots of fun.

 

[ronaldrc]

It sounds to me like some one has at one time suggested to you that you could use what we use to call a running thread coupling.

Thread the original thread too twice the length then run your coupling all the way upon your pipe the full length of the coupling. Then take the adjoining pipe and hold it to the end at the coupling joint and back the coupling backwards on to the other pipe.

I never would do it and it is not legal. You can not tighten it and you can't make it water proof. And it will be turned down if it is inspected.

I would suggest a cap 90, LB or 3 piece coupling.

Ronald

 

[iwire]

You can not tighten it and you can't make it water proof.

Normal RMC couplings are not water tight, they have straight cut treads.

 

[ronaldrc]

Normal RMC couplings are not water tight, they have straight cut treads.

Thanks Bob I should have said raintight?

 

[Wes G]

Thanks Bob I should have said raintight?

Maybe rainproof would work better. "-tight" generally refers to the inability of whatever (rain or dust) to enter the system. "-proof" refers to the design that while allowing the substance to enter, keeps it from interfering with successful operation.

Wes