Running EMT without offsets

[Tsemple]

Hey Everyone,

I have a project where I need to splice a heat trace into a circuit at some exposed downspouts every 25' along the side of a 800' long warehouse. I'm looking for a way to run 3/4" EMT without doing box offsets to save headaches while pulling cable.

Essentially from the control cabinet I'll go 25', JB, another 25', JB ect. every 6 drops I need to start a new circuit. I have limited space to run conduit so I can't do a bunch of dedicated runs out to each drop. See below



I have no problem putting box offsets in but the bend counts get wild when I think about actually pulling cable. I Would like to keep the conduit straight for ease but the options I'm coming up with aren't great:

1) Cut some 5/8" unistrut into small pieces, strap it to the building and strap the pipe to it
2) Run 1" EMT instead of 3/4" so the offsets are minimal and the conduit is roomy
3) strap the pipe with mineralac straps (mini's) direct to the building face to stand them off the building for straight box entry
4) Run the 3/4" with normal offsets and install a larger JB every 6-7 drops as a pull point and splice everything through at each of these locations.

Frankly I don't really like any of them, I'm thinking option three is easiest from a labor perspective but I've never used those straps like that, not even sure if its code compliant in NY where this is going.

Any thoughts?

 

[rc/retired]

Well, offsets are not required by code.
If this is inspected and you get a hotshot inspector, the inspector may cite something really stupid as "neat an workman like manner".
IMO, this is your call.

Ron

 

[petersonra]

Why do you need to do box offsets? is there an outlet at each downspout?

 

[tank728]

http://www.aimedia.co/media/images/CB1.jpg

Maybe something like this

 

[Tsemple]

http://www.aimedia.co/media/images/CB1.jpg

Maybe something like this

I've never seen something like this before, interesting.

As for why we need offsets, purely out of habit, running pipe without box offsets makes my brain itch. That being said having box offsets that don't match exactly would do the same thing haha

I'll think about the no offset approach, strap 2'6" away from either end of the box and call it a day, should making pulling nice and easy.

 

[Todd0x1]

I feel like not bending the offsets and using regular straps is going to look not that great, unless it's really high and you can't see it. I'd probably use minis with the added benefit you can install them before any pipe (and they'll help hold the pipe while you're installing it). Set up a laser to get them all straight and go along with a scissor lift putting them in. Is it a metal building or concrete?

 

[tom baker]

If it’s a metal red iron bldg use a caddy strap
Or Arlington clic its, install first then push emt into it and it snaps closed. Faster than a mineralac

 

[roger]

Do people not have offset kickers anymore? Just asking, not trying to be critical.

 

[Todd0x1]

Do people not have offset kickers anymore? Just asking, not trying to be critical.

I think its not so much bending the offsets, but he's pulling a set of conductors uninterrupted through alot of boxes and offsets will cause the pull to have too many bends.

 

[roger]

I doubt the offsets will make enough difference to worry about. Besides that he could pull through x number of boxes and drop back to install devices when he gets to a point that the pull becomes to hard.

 

[tom baker]

This i

If it’s a metal red iron bldg use a caddy strap
Or Arlington clic its, install first then push emt into it and it snaps closed. Faster than a mineralac

Clic it is the orginal name. Arlington bought and now it’s this (I used these a lot with PVC)

Arlington | QuickLATCH™ Non-metallic Pipe Hangers

One piece. UV rated plastic for outdoor application.

www.aifittings.com

 

[qcroanoke]

http://www.aimedia.co/media/images/CB1.jpg

Maybe something like this

We use those things by the case. Great time saver once you get used to using them

 

[Tsemple]

Hey Guys, Thanks for all the feedback.

Do people not have offset kickers anymore? Just asking, not trying to be critical.

Offset kickers are a still a thing, but we're working out of state on this one and are running light, i would have to ship one in or buy one just for the project which I'd like to avoid.

I doubt the offsets will make enough difference to worry about. Besides that he could pull through x number of boxes and drop back to install devices when he gets to a point that the pull becomes to hard.

I am indeed worried about all of the bends with these long pulls, even if its 20 degrees per offset (back to back 10 degree bends) thats 40 degrees per box so every 8-9 boxes I's be at 360 degrees and pulling will get interesting. Not the end of the world but with the crew that will be doing the prep work on this I want it to be as simple as possible.

If it’s a metal red iron bldg use a caddy strap
Or Arlington clic its, install first then push emt into it and it snaps closed. Faster than a mineralac

I looked into those arlington quicklatch hangers but with this being on a building exterior I'm concerned about the plastic breaking over time.

There are also 2 different sides to this building, on one side it will be mounted to concrete, the other side to metal.

I think the best course is going to be those hanger straps and let them rip. Thanks again!

 

[rambojoe]

Cruise through the caddy catalog.. They have a section for pearline straps. They have a bang on for you, and box supports... M24s's still might work.

 

[LarryFine]

They have a section for pearline straps.

"Purlin", but who's counting?

 

[rambojoe]

Yeah, i was at a lost for that spelling... Thx. I used to have their catalog in the bthrm... Not there...

 

[rambojoe]

Im a bang on guy- hammer and channels...

 

[winnie]

I am indeed worried about all of the bends with these long pulls, even if its 20 degrees per offset (back to back 10 degree bends) thats 40 degrees per box so every 8-9 boxes I's be at 360 degrees and pulling will get interesting. Not the end of the world but with the crew that will be doing the prep work on this I want it to be as simple as possible.

I think this might be one of those situations where theory and practice are widely divergent.

In _theory_ every bend adds up exponentially to multiply pulling force. However in this _theory_ the thickness of the wire and the diameter of the conduit are not considered. With the offset kicks that you describe, the wire could actually remain straight passing through the offset region and not 'see' the bends.

You alluded to this concept when you considered using larger diameter conduit; you need to kick up what 3/8"? 1/2"? If you have a 1" conduit then the 'kick' is smaller than the diameter across the conduit, and the wire will simply go straight through.

With that said, I think you are right to at least consider this issue, and an inspector could easily ding you on it.

One further consideration is that code requires you to have 'pull points', but doesn't actually require you to use them. If you have 360° between pull points but actually do your pull with 720° from start to finish, you are still kosher.

-Jon

 

[roger]

With that said, I think you are right to at least consider this issue, and an inspector could easily ding you on it.


-Jon

I don't think he's describing more than 360 deg between pull points, he just wants to pull through a number of boxes at one time. I would pull through all of them if it were me. As you pointed out "the wire could actually remain straight passing through the offset region and not 'see' the bends".

 

[winnie]

Also, do the math on using shallow angles for your box offsets. A 1/2" kick with 3° bends back to back (12° per box) puts 10" between each bend. You'd probably want to set up some sort of shallow angle jig to do all the kicks, but I think you could make shallow kicks work with standard conduit strapping.

-Jon