How to assemble RMC in the field?

[BretHeilig]

This might be in the wrong forum, sorry if that's the case.

I just moved from CA to NYC, and outdoor conduit is mostly RMC here. I'm licensed in CA, but I just haven't done a lot of work in rigid. I don't want to seem like an idiot when I show up to work: how is threaded conduit assembled in the field? It seems like you'd have to turn a 10-foot long piece of pipe counter-clockwise ten or eleven times to seat it in a coupling... that usually can't be done if it has any kind of bend in it. Is it that the couplings have opposing threads, and you turn the coupling? I searched for that, but can't find any indication that's how it works. Any advice?

 

[SiddMartin]

they have threadless CPLG and Connectors, compression type. I'm sure NEER / Arlington has them.


edit : I use these when ever possible

 

[e57]

Yeah I assume the only RMC you would use here often in most markets would be OH services....

You turn it wrench tight....

But before you do that you plan out how it will go together, and how many of these 3-piece unions you can avoid using....

If you plan it well it should be none.... Don't be afraid to turn a box onto ON TO the conduit before to secure it. And make sure bends are just right before you cut and thread.

Otherwise - yes there are threadless connectors - but they cost money.

I'm sure you'll have a lot of fun the first few times....

 

[Electrical guy]

they have threadless CPLG and Connectors, compression type. I'm sure NEER / Arlington has them.


edit : I use these when ever possible

Question, when you use these types of connectors do you have to run a seperate grounding conductor because you have changed the integrity of the connection.

Thanks,

 

[cpal]

Question, when you use these types of connectors do you have to run a seperate grounding conductor because you have changed the integrity of the connection.

Thanks,

most fittings are listed for grounding but you are supposed to make sure.

 

[infinity]

Even with a reasonably short elbow on the end of a 10' length you can thread one piece of pipe into a coupling. The coupling is sloppy enough to permit threading into it. Make sure that the coupling is threaded all the way on the first pipe and then start it on the second piece for a few threads by backing it off. If you need more room to spin the elbow you can remove the straps back a length or two to get more room to turn the elbow in. They do make threadless fittings which allow you to essentially run RMC like EMT.

One last thing, RMC is 10' with one coupling attached.

 

[steve66]

This might be in the wrong forum, sorry if that's the case.

I just moved from CA to NYC, and outdoor conduit is mostly RMC here. I'm licensed in CA, but I just haven't done a lot of work in rigid. I don't want to seem like an idiot when I show up to work: how is threaded conduit assembled in the field? It seems like you'd have to turn a 10-foot long piece of pipe counter-clockwise ten or eleven times to seat it in a coupling... that usually can't be done if it has any kind of bend in it. Is it that the couplings have opposing threads, and you turn the coupling? I searched for that, but can't find any indication that's how it works. Any advice?

I'm not an electrician, but I had the pleasure of running some RMC in a previous life. Turning the coupling will tighten the threads on one end, while loosing them on the other end. So you can't just turn the coupling. (Although, you may have a good idea if you can also make a backwards die to thread the pipe.)

But E57 has it right, you plan out your run trying to avoid having to turn bends. Most of the electricians I worked with took a lot of pride in trying not to use a union unless absolutely necessary. And when they did, they usually screwed about 3 different bends together, and then attached it at the union.

Some electricians didn't seem to care, and would use unions eveywhere. Those runs with lots of unions usually weren't plumb or square or pretty either.

 

[nakulak]

as others said, a well planned run will have no unions. sometimes its unavoidable. sometimes you want to have a union.

 

[e57]

I should have mentioned these things before....

BOTH unions, and threadless connectors and couplings cost money - so does your time.... Thinking a few things out quickly can take a little time after some experiance. Scratching your head for an hour cost more money than a few threadless fittings.... The trick is knowing which.... (as it is with all things...)

Depending on what you're provided with and what size - there are some other factors. Truthfully I pull out my band saw on just a single stick of 1/2" EMT - some might think that lazy but I don't. Over 3/4" IMO all of these should be the later of the list below... 3/4", and less depends on the size of the job IMO.

• Hack-saw or pipe cutter vs band saw or the cutter on a threader.
• Hand threader vs. power threader
• Hand bending vs. power bending

As far as threading goes - remember to re-coat the threads, and as far as support - some people preffer one hole 2-piece backed straps... (You'll find that out day one. If you get handed a maluable iron strap - ask for the other piece... )

As far as bending skills - planning first! But just a little (lot) more attention to details like take-up amounts on off-sets and 90's can do a world of good in RMC. (google 'porcupine press'...) And having a little solar calculator is not cheating. (Neither is a regular/metric tape measure..)

 

[growler]

I just haven't done a lot of work in rigid. I don't want to seem like an idiot when I show up to work: how is threaded conduit assembled in the field?

Don't worry about it, if you haven't run rigid before then assembling it is going to be the least of your problems.

Running rigid conduit is a whole differnet skill set and the best thing to do is let the guys you are working with know that you are not a rigid man and let them teach you the tricks of the trade. Everyone has to learn some time and no one started out perfect, it will take some time.

 

[e57]

Don't worry about it, if you haven't run rigid before then assembling it is going to be the least of your problems.

Much of CA RMC and EMT is replaceable with glue-up PVC - I get very experienced guys who other than for a few things rarely use RMC for anything... While they may even be great/awesome with EMT (which is a lot more forgiving) - RMC is a slightly different ball game.

 

[e57]

As far as bending skills - planning first! But just a little (lot) more attention to details like take-up * amounts on off-sets and 90's can do a world of good in RMC. (google 'porcupine press'...) And having a little solar calculator is not cheating. (Neither is a regular/metric tape measure..)

* Meant to add shrinkage in there too - Take a look at page 8 (7 of 9 if printed)

Finding a finished length and cutting and threading threading first is key IMO. While sometimes you can't it is 100% if you can.

 

[buldogg]

On one job I was on once, an electrician that wasn't comfortable with making bends used all pull elbows.

 

[BretHeilig]

Hey thanks all for the excellent advice!

 

[Karl H]

Don't worry about it, if you haven't run rigid before then assembling it is going to be the least of your problems.

Running rigid conduit is a whole different skill set and the best thing to do is let the guys you are working with know that you are not a rigid man and let them teach you the tricks of the trade. Everyone has to learn some time and no one started out perfect, it will take some time.

This is what I was thinking when I was reading this thread.

I favor the guy that fesses up and admits he has never done
a certain task verses the guy that says,"Dude I've done this hundreds
of times!" Then you come by and find this guy still trying to fit
a run of RMC or it looks like a child did the work.

Like others have said, PLAN and know your shrinkage.

I too prefer the two-piece one holes on single runs especially
in fork lift areas.

 

[Rockyd]

Pretty good commentary for a thread where journeyman
knows what he doesn't know". I agree with the others, let the learned lead" and you will pick it up quickly. Something to think about is the proper placement of unions. In the oilpatch, we use unions for all larger junction boxes. Reason being, if you had to replace the box, you stand to do so within a reasonable time dollar situation.

Other than as previously mentioned, through proper planning, you should be able to do most jobs with a nominal number of Eriksons (three piece couplings).

Buy a copy of Ugly's Electrical references at any Homeless Depot and they have some fair advice for starting out.

 

[ishium 80439]

My background was pretty varied. Than I went to work for a company that specialized in fueling stations. With over a decade in the trade I was "reduced" to asking my apprentices for advice.

It actually estalished a great relationship. I knew a bunch of general stuff and they knew a bunch of specific stuff. They asked me about broad brush stuff and I asked them how they had seen these particular dispensers done before. There was a pile more RMC than I'd ever seen before. I got to the point where I was better w/ that than I was w/ EMT.

The key is plan where the 1 union is going to go. Of course keep in mind that I was doing underground and turning up into these little boxes. Unions were a necessity. I'm not sure about long exterior runs.

The true key is don't be afraid to admit what you don't know. You can always find someone who can perform a specific task. The trick is to find that person and incorporate them into your job.

I'm sure you are already experiencing this but culture shock is tough to deal with. Different language, techniques, ways of doing business. There is no one right way. But when you get used to one it is tough to adapt to another.

Good luck.

 

[realolman]

One more time... plan before you bend. You know you're going to have this difficulty so look for how you will thread the pieces together before you cut ,thread, and bend them... You may thread a bunch of stuff together before you hang it so you have room.

Many times you will just use as short a bend as possible to have room to thread it.
If you need a bend in the middle of a piece of pipe, you probably will want to cut it so that you have a short bend and two pieces. If you bend it in the middle it will probably show you why you shouldn'ta oughta done that....

erickson's are always an option if you absolutely need them, but don't use them or LB's and such unless you have to ... my God, man...You're an electrician... have a little pride

I think there are seven threads on a piece of RMC... seems to me when I fling the hand threader around to take it off, it takes seven turns to become free.

 

[hardworkingstiff]

In case you didn't catch it, plan before you bend, know your bender, think, think, think. It makes it so much easier.