RMC Cut & Threads

[Alwayslearningelec]

Like to know, from estimating standpoint, if my assumption on # of cut/thread required seems about right? Obviously you can not always be 100% accurate...hence estimating.

1. 150' run from a panel to a panel. with a pull box in the middle. Bends and not factory elbows. If starting you run at the panel would not need and cut/thread there. At one side of the pull box I would figures a cut/thread as don't know if box will be right at full stick. WOuld not figure a cut/thread on other side of box as would start a full length there. Would figure a cut/thread where ending at the panel as may not end with full stick. So two cut/ threads/ Make sense?

2. 150' run from panel to panel with one C conduit body and 2 factory elbows. Same as above for starting and ending at panel. Would figure a cut and thread at one side of the conduit body and factory elbows. Make sense?

 

[don_resqcapt19]

The installation of bends often requires a coupling because you cannot spin a large bend on. I would be looking at 4 to 6 cuts and threads for the 150' run, and more than that if you use factory bends.

 

[Alwayslearningelec]

The installation of bends often requires a coupling because you cannot spin a large bend on. I would be looking at 4 to 6 cuts and threads for the 150' run, and more than that if you use factory bends.

Thanks I don't follow the whole needing a coupling on a field bend I know this is been explained several times but I just can't grasp the concept. If you're attaching a stick of RMC onto the end of a bend you should not need a coupling because that stick has the coupling correct.

 

[don_resqcapt19]

Thanks I don't follow the whole needing a coupling on a field bend I know this is been explained several times but I just can't grasp the concept. If you're attaching a stick of RMC onto the end of a bend you should not need a coupling because that stick has the coupling correct.

Just depends...lots of times you don't have room for a full length at the end of the bend. What size conduit are you talking about. I can't imagine going to that amount of detail in an estimate for conduits 2" and smaller.

These type of issues are why estimators without field experience win a lot of jobs that lose money.

 

[kwired]

the need to thread an extra time or two hopefully isn't going to make or break whether you profit on this job or portion of the job, even if you are hand threading 2 inch.

When you have pieces with bends in them, sometimes it can be difficult or even impossible to thread them onto the end of what you have run so far. Sometimes you can thread couple pieces together then hang them which may result in fitting one piece measuring out the next piece then take first one back down and thread them together before putting both up together. Sometimes you simply can't put it together without a union/three piece coupling or even compression type fittings. Other times you may be able to put a shorter piece on with little trouble then continue running full pieces. Some of that you won't be able to predict where you might need to do something a little out of ordinary until you get to that point of the installation.

 

[LarryFine]

And sometimes the leg points the wrong way when the couplings are tight.

 

[kwired]

And sometimes the leg points the wrong way when the couplings are tight.

Takes some experience to get the feel of when one more turn will work and when it likely won't.

 

[LarryFine]

Takes some experience to get the feel of when one more turn will work and when it likely won't.

I try to leave several joints a little loose and tighten them at the same time, and go for what you describe.

 

[Alwayslearningelec]

Just depends...lots of times you don't have room for a full length at the end of the bend. What size conduit are you talking about. I can't imagine going to that amount of detail in an estimate for conduits 2" and smaller.

These type of issues are why estimators without field experience win a lot of jobs that lose money.

Well you see I'm detailed and always usually know close to how it should be done, hence all my questions on this forum. Not your average estimator here. Thanks for the feedback. When your referring to not having the room for a full length you mean the piece being bent or being attcheched to the bend peice?

 

[Alwayslearningelec]

Just depends...lots of times you don't have room for a full length at the end of the bend. What size conduit are you talking about. I can't imagine going to that amount of detail in an estimate for conduits 2" and smaller.

These type of issues are why estimators without field experience win a lot of jobs that lose money.

Also why do you say for 2" and smaller? Larger conduits A LOT more time???

 

[Alwayslearningelec]

the need to thread an extra time or two hopefully isn't going to make or break whether you profit on this job or portion of the job, even if you are hand threading 2 inch.

When you have pieces with bends in them, sometimes it can be difficult or even impossible to thread them onto the end of what you have run so far. Sometimes you can thread couple pieces together then hang them which may result in fitting one piece measuring out the next piece then take first one back down and thread them together before putting both up together. Sometimes you simply can't put it together without a union/three piece coupling or even compression type fittings. Other times you may be able to put a shorter piece on with little trouble then continue running full pieces. Some of that you won't be able to predict where you might need to do something a little out of ordinary until you get to that point of the installation.

This is the concept I can't wrap my head around? I'm tryng to envision this scenario.

Is the pic I'm showing what you mean? What would prevent spinning the bent length onto the installed length?

 

[LarryFine]

This is the concept I can't wrap my head around? I'm tryng to envision this scenario.

Is the pic I'm showing what you mean? What would prevent spinning the bent length onto the installed length?

Just one conduit in free space, no problem. Several in parallel, against a wall, or on strut, not so easy.

 

[Dsg319]

Takes some experience to get the feel of when one more turn will work and when it likely won't.

Then There’s still the guy beside you who insist on one more turn

 

[Alwayslearningelec]

Just one conduit in free space, no problem. Several in parallel, against a wall, or on strut, not so easy.

Ok, I get it now. So alot of the conduit we are running now( RMC Aluminum) has all parallel runs. Each bank is anywhere from 4 to 16 conduits and we have about 15,000' of conduits. Each bank has many bends, probably anywhere from 6-10 bends( small offsets and 90's). With that said I guess this is going to pose a big problem for the field guys. So when you have a situation like the one I describe regular couplings probably won't work correct? And our guys aren't that expereinced doing this. Uh oh.

 

[don_resqcapt19]

Well you see I'm detailed and always usually know close to how it should be done, hence all my questions on this forum. Not your average estimator here. Thanks for the feedback. When your referring to not having the room for a full length you mean the piece being bent or being attcheched to the bend peice?

I am sorry but there is no way an estimator or even the project foreman will know how many cuts will need to be made until the electrician actually installs the conduit.

 

[don_resqcapt19]

Also why do you say for 2" and smaller? Larger conduits A LOT more time???

In general, the costs for conduit larger that 2" are about double that for 2" and smaller.

 

[don_resqcapt19]

Takes some experience to get the feel of when one more turn will work and when it likely won't.

That is what the 48" aluminum pipe wrench is for....but I have seen conduit bodies and a few couplings split when you tried to get that extra 180° of turn.

 

[don_resqcapt19]

Ok, I get it now. So alot of the conduit we are running now( RMC Aluminum) has all parallel runs. Each bank is anywhere from 4 to 16 conduits and we have about 15,000' of conduits. Each bank has many bends, probably anywhere from 6-10 bends( small offsets and 90's). With that said I guess this is going to pose a big problem for the field guys. So when you have a situation like the one I describe regular couplings probably won't work correct? And our guys aren't that expereinced doing this. Uh oh.

If the electricians are not experienced in this type of install, plan on a lot of expensive 3 piece couplings, or if in a classified area, much more expensive explosionproof unions. Also, plan on about doubling the labor units from your labor unit book if they don't have the experience.

 

[kwired]

This is the concept I can't wrap my head around? I'm tryng to envision this scenario.

Is the pic I'm showing what you mean? What would prevent spinning the bent length onto the installed length?

View attachment 2572585

Can you spin that piece with the elbow on it or does the deflected portion hit walls, ceilings, other conduits in the row of conduits, etc?

Can you take a strap or two loose on the already installed pieces and get enough movement to spin the piece with the elbow on?

Every installation has it's variables and there is no one general answer to this without factoring in site conditions.

If the end of last installed piece is only a foot from a corner and your run is to turn the corner, no way you are threading on a full piece with only 1 foot stub connecting to end of what is already run. If it were say over 1 inch conduit no way you even bending a 1 foot stub, so the last installed piece will need cut somewhere just to get any piece with an elbow on.

Again much of this is hard to plan for as it won't necessarily be known until you get to that part of the installation. Then comes mistakes in cutting, bending, etc. that may add to your overall cost. But you should have enough excess factored in to cover those as unexpected things will happen from time to time.

 

[LarryFine]

The moral of the story is that it will take twice as long, and require twice as many cuts as you think it will.