bending a 3/8" box offset with 3/4 EMT

[mod600]

So I spent the weekend wiring up lights in my shop. First time using/bending conduit (3/4" EMT). It obviously is an art and takes a bit of practice. For what I was doing wasn't too bad...but for a newbie like me...it was enough of a challenge. I got everything bent and ran how I wanted, so I guess that is the main thing although it took way longer than I had hoped. My biggest struggle is bending a simple 3/8" box offset. Basically when running the conduit tight against the wall, and then having it lift off of the wall roughly 3/8" to enter into 4x4 box. My manual has a guide, but the smallest offset was 2"...anything less than that appears to be a trial and error deal. I tried to use the formulas and calculated where my bend marks should be to align with the bender, but they never worked. According to what I've found online, offsets like this are so small, that it just takes trial and error to see what works... So this is where I ask the experts out there....when you bend an offset like this how do you go about doing it. I know it won't be exact, but a good starting point of what works for someone would be a nice place to start...these bends should be pretty common and easy to do....so any tips/suggestions would be great. It'll be awhile before I tackle the rest of the wiring...but having a place to start would make it easier for the next round.
Thanks!
mod600

 

[frankush]

Bending pipe is an art. Just like painting, some are better at it, than others. All benders will give varying results, so you have to play with it a little. I am not a fan of aluminum hand benders for just that reason. I'm assuming your bender uses the Benfield method. Try this. Insert your pipe in the bender and leave about a 1/2" stick out. The bender should have an arrow, a notch and a star. Make a mark at the notch. Measure 3" from that and make a second mark. Extend your marks all the way around the pipe. Put the pipe back in the bender and line up that first mark with the notch again. Degree marks are located on both sides of the bender head. Holding the bender with the head up and the handle against the side of your foot, bend it to about 10 degrees. A tad less is better. Slide the pipe to the second mark while rotating the pipe 180 degrees. Bend at the notch once again. Rough bend is done. If you put the same amount of bend into each bend, they should be parallel. The notch mark indicates the center of the bend. You can put more or less into either bend to true it up. If you don't have that magic 3/8", you can bend it a touch more if it's less than 3/8"s or take some out if it's too much. The pipe will only take so much before it looks like doo doo. If you are slightly off that 180 degree rotation you'll have a dog leg. The bend will go left or right of center. You can use the bender to correct it. If you screw it up, you wasted 6" of pipe. Cut it off and try again. No romex where I live. So after 30 years you learn not to get frustrated. Practice is your friend. I once had a boss that said if he could train monkey's to bend pipe, he'd hire them.

If you consistently find, that your offset is greater than 3/8", make your first mark at 2-3/4".

 

[CADPoint]

There's and app for that

This is called a box offset.

You need to usa a bend of 2.16" which is two inches and a little more than an 1/8"
This is the slightest of kicks that is marked on some benders! = 10 degree's,
The back of pipe should be parallal to this bend mark. the edge that is farest away from you.

but the smallest offset was 2"...anything less than that appears to be a trial and error deal. I tried to use the formulas and calculated where my bend marks should be to align with the bender

Off end of pipe mark distance of 2.1/8" + pencil width.

The pipe will not look like a equalator triangle - I'm saying that becasue the second bend is so close and the second bend is not usually rolled across the ground.

Hope this helps.

 

[Zeke]

First of all, why can't you use these?

It would be great to be able to fabricate one of these:

 

[jjpp]

First of all, why can't you use these?

Where would the fun be in that????
Just kidding It might cost a bit more than a straight fitting but other than that can't see why not.

 

[m.b.0331]

Here's a helpful video: How to Bend a Box Offset, by Lowes Home Improvement.

 

[madosta]

First of all, why can't you use these?

Where would the fun be in that????
Just kidding It might cost a bit more than a straight fitting but other than that can't see why not.

Does anyone know if these have the same fill as a straight connector with a bent offset? I don't think you can fit as much through those.

My bender has an 11 degree mark, I use that then flip and have only gotten comfortable doing an offset with about 15 or so bends.

 

[zmaxmotorsports]

I normally put the end of conduit flush with end of bender for first bend,then mark 6" back and roll pipe 180 degrees for second bend on box offsets so they all come out the same.
I never really cared for doing the math on box offsets,after 30 years I got to be really good at eyeballing them.
As far as stup ups/90s just remember to subtract your take up on the bender from the length you want.
For 1/2" emt its 5"
For 3/4" emt its 6"
For 1" emt its 8"
If you want a 24" tail on a piece of 1/2" mark it at 19" and thats where the arrow on bender lands(point the other end of 19 away from you when you bend it.

 

[zmaxmotorsports]

Does anyone know if these have the same fill as a straight connector with a bent offset? I don't think you can fit as much through those.

My bender has an 11 degree mark, I use that then flip and have only gotten comfortable doing an offset with about 15 or so bends.

The problem with those cast offsets other than being expensive and not looking good is thats a really hard offset in that short of an area,Easier to pull wire in a longer more gradual bend especially right into a box.

 

[frankush]

Here's a helpful video: How to Bend a Box Offset, by Lowes Home Improvement.

Are you kidding? That 10 degree bend looks a lot like 45 degrees to me. The first bend also prevents him from setting the bender on the ground to make the second bend. Good way to kink pipe. Don't waste your time watching that joker.

For small bends it's easier to flip the bender up so you can see the degree mark. 1/2" pipe also requires a lot less umph to bend. 1/2" EMT requires very little force to bend. If you already spent the money on a bender, use it. The offset bender in Zeke's post is expensive, works well and is never seen on a jobsite. It's like having a $200 drill that can only drill 1/4" holes.

 

[m.b.0331]

Are you kidding?

Yeah, but Lowes isn't. Poor dude probably got to work Monday and was handed a camera and a bender. It's amazing that Lowes still has the video up; maybe they want homeowners to watch it, then burn through a whole bundle of pipe trying to bend a box offset.

 

[rburke65]

That video is a total joke!

 

[mod600]

Thanks for the suggestions guys. I will have to try the above technics and see if I can get them to work. Like I said I made it work for my first set of lights. But when I do more outlet boxes I'd like to have the process figure out better. I was lining up on the arrow on the bender and not the star, so that might have been part of it. Thanks again!

 

[Tyberius]

The emt is soft enough that you can tweak a bad bend back to good. The handle side of your bender will slip over your pipe and you can fine tune it.

Those premade offsets are way too expensive compared to the cost of the conduit, and you can't hardly pull through them.

 

[legotech7]

Bending conduit... Mistakes.....

Finally started to add electricity to my metal building. Am up to putting the conduit in... Easier said than done. Every thin else has been fairly easy to do. I am a complete novice at this and am learning as I go along. But the conduit thing...... has got my goat. The runs in my set up look fairly easy to do, mostly straight. I just started running for my outlets, but already I ran into a snag. I need to do an offset off a 90 degree bend to a metal stud and then straight down. I got my calculations all fubared. Just couldn't make that bend!..... The offset need s to be about 3 inches. Is there a prebent offset one can purchase with that much offset? I don't care about using the ready made stuff, I just need to get this project done. Any help would be greatly appreciated. Here are some pics to show what I'm talking about. Like I said, this is all a first for me, so laugh all you like, but if you can teach me something, I thank you...... The first pic was my try at the off set...not so good... the second, as you can see is just straight up, then to the right , then up untill the 90 degree, then it went all to hell......

 

[Charles (in GA)]

http://www.cefga.org/documents/BendingRaceways.pdf

Best document I've found for bending conduit. I have to relearn every time I do it after I've been away from it for a time.

 

[Norcal]

What is the elbow under the panel in the 2nd photo? Looks like a plumbing fitting. The Greenlee Little-Kick that Zeke posted is the cats meow, but you'll choke on the price.

 

[_Dock_]

I'll try to help where I can... can you explain more or maybe post a pic of a drawing of what run you are trying to make. If you are trying. To make a back to back 90 you won't be able to do it with only 3 inches.

What size pipe are you using? What is that second bare copper ground wire from/for?

 

[skulldrinker]

If all else fails 'bend then cut' .

 

[zmaxmotorsports]

Look up jack benfield.

 

[sberry]

I bend them by eye too. Very rarely do I do an actually calculation in any kind of common work. Tape measure, marker and an occasional square and make a patteren once in a while but that's about it. I got the offset tool for 1/2.

 

[alfredeneuman]

All Little Kickers produces bends that are 1/2".

If you use them, you'll be forced to roll the bends over to fit in a standard KO or the box won't fit flush against the wall. It becomes a real issue when you've already bent the EMT with a bender elsewhere on the conduit.

 

[The FIB]

Look up jack benfield.

Years ago, the electrical supply house I used would give away one of his
handbooks with every purchase of a new bender.

 

[toplessHO]

you can use backstraps and spacers and not bend pipe at all.

 

[3rdgen]

What I do because I hate when all the offsets are different ( major ocd issues ) is measure 3'' and 5'' from the end of the pipe and then bend just a touch less then 10 degrees. Works pretty good but does take some practice to get perfect.

 

[sberry]

I found that in the end no one notices but the installer. It looks good to the rest of the world and respectable from other trades people. We would like to think someone cares but unless its obvious they don't look that close.

 

[BreeStephany]

First of all, why can't you use these?

I could never imagine trying to pull wires through one of those and it will likely derrate the maximum wire fill for the conduit.

 

[speed bump]

I found that as an amateur I spend a lot of time tweaking it to perfection and then realizing no one but me cares. So unless its something I fixate on I just try to get it close enough that my mistakes aren't obvious from across the room.

 

[JACDes]

Do it enough times and it becomes second nature.

I make box offsets by eye but I have been involved with rehabbing houses since I was 15so plenty of practice.

I leave about 2"-3" of conduit sticking out past the end of the bender. I make a slight bend,prob 20 degrees.. then I rotate the end and bend it the other direction until I get the offset I need. Works like a charm hard to explain, easier to show.

 

[JACDes]

Assessing plenty of jobsites as a project manager I have taken great pride in my weekend work when I realized the "pros" do it the same quality as me & sometimes worse when it's all going to be hidden by sheetrock LOL.

For exposed work you want the pipe and boxes to be straight / level / plumb.

No one is going to nit-pick how you did the offsets.. unless they have OCD, or are an A-hole.

 

[sberry]

Even a folksy offset looks better than the adapter.

 

[mod600]

It's been a while since I first posted my question. I have not had time to do anymore electrical work that requires conduit. But I'm sure I'll be a back to reference this post when I get back to it. Thanks again for all the comments and suggestions.
mod600