How to Bend a 3 or 4 Point Saddle in an EMT Conduit
3 and 4 Point Saddles
This section of the conduit bending guide will address bending both 3 point and 4 point saddles in emt conduit (they can also be bent in either IMT or rigid conduit as well using the same procedures).
These are the two common saddle bends made in electrical conduit by electricians, used to temporarily raise the run of conduit above a small obstacle, such as another conduit running across the path of the conduit to be saddled.
While saddles, and in particular 3 point saddles, are the bane of many otherwise excellent electricians, there is no need for this to be. Even the dreaded 3 point saddle is quite easy to bend, and bend in a manner consistent with quality workmanship.
Each type of saddle is bent differently and usually used for different purposes. Lets start with a 4 point saddle as it is easy to understand and is used by novices without even recognizing they are doing it.
If interested, you will find other links to other sections of the complete conduit bending guide at the bottom of this article.
Bending A Four Point Saddle
It its simplest form, a 4 point saddle is nothing more nor less than two offset bends a short distance apart. Normally used to cross larger obstructions than the 3 point saddle, they have a definite place on the job site.
For saddles greater than about 3", a 4 point saddle is probably the way to go. Begin by measuring the distance to the obstruction and marking that distance on the conduit. For example, if that measurement is 40", make a mark 40" from the end of the conduit. Measure the height of the obstruction; it is common to add perhaps ½" to this measurement to make sure the saddle will easily clear. Decide what angle you wish to make your offsets, and, using the appropriate multiplier, determine the length of the offset. To continue our example, if the height is 5" and you will be bending on 22° the length of each offset will be 5 X 2.6, or 13". If you are not familiar with bending offset bends, this might be a good time to review "How to bend an offset" section of the complete conduit bending guide (the link will open in a new window, leaving this window intact). You should always use the gentlest bend you can as it will make pulling wire much simpler and may save adding a junction box simply because you have crossed the legal limit of 360° of total bend between boxes. For instance, using 30º bends means a four point saddle will use 120º total, leaving only 240º of the legal 360º, while using 22º bends will leave just over 270º, or a full three 90's.
Measure back from the first mark on the conduit towards the beginning of the pipe the length of the offset and make a second mark. To continue our example, you will now have a mark at 40" and one at 27" (13" back from the first mark).
Measure the length of the obstruction and once more mark the conduit that distance past the first mark. If the obstruction is 10" wide, you will now have marks at 50", 40" and 27". Normally, the second offset is bent at the same angle as the first (although that is not necessary) as it will look better; mark that distance. Your final mark will thus be at 50" + 13", or 63". You should now have marked the conduit at 27", 40", 50" and 63" for our example.
A word on shrinkage. The total length of the conduit will "shrink" as it is bent; this is because some of the length is going up instead of straight. It is possible to calculate the shrinkage and the calculation is shown in the section on "The math behind bending conduit" but there are several variables that affect the shrinkage and it is not a simple calculation. In practice if appearance is very important as in exposed work most electricians will increase all the measurements by a few inches and cut the conduit after test fitting it. In this manner the saddle can be centered exactly over the obstruction, but this is seldom necessary except for exposed work.
4 Point saddle bends
Begin bending by fitting the conduit into the bender with the very toe of the bender lined up at the 40" mark (in our example) and pointed toward the 50" mark. Bend the conduit to the desired angle, 22° in our case. Slide the conduit down until the 27" mark is in the same place, right at the toe of the bender, rotate the conduit 180° so that the bend will be in the opposite direction, and make the second bend. By using the very end of the bender to line the marks on the saddle will be just a few inches wider than the obstruction, guaranteeing it will fit. It is possible to use the more common marks such as that used for bending a 90, but the complete saddle will be exactly the right size and conduit shrinkage will prevent it from fitting properly.
Turn the conduit around and make the third bend with the 50" mark at the very toe of the bender and the toe pointed toward the 40" mark. Bend the conduit in the same direction as the very first bend. Take great care to make sure the bends are all in a straight line; sight down the conduit very carefully before bending and rotate the conduit until all the bends line up exactly. It is very easy to "dogleg" the bends, meaning that the completed saddle will not lie flat on the floor if laid down sideways and it is difficult to remove that dogleg.
Slide the conduit forward to the 63" mark and, after rotating the conduit 180° once more, make the final bend. The saddle is complete; the run of conduit may now cross the obstruction without difficulty.
One of the advantages of a 4 point saddle is that it can be broken in the center, using 2 pieces of conduit to make the complete saddle. Each piece gets 1 ordinary offset, but the total package is still a saddle.
Bending A Three Point Saddle
While many electricians will bend a 3 point saddle with a center bend of 45° a better solution is to make that center bend at only 22° as the total degrees of bend required goes from 90° down to only 45°. To do this you will need to mark the bender at the center of a 22° bend. Using a piece of scrap conduit, make a 22° bend, remove it from the bender and lay it on a table or floor. Find the center of the bend and mark it - eyeball visualization will do fine. Insert the conduit back into the bender at the same location it was and transfer that mark to the bender. A more permanent mark can be made by filing a notch in the edges of the bender, just as is done at the factory for the center of a 45° bend on some benders.
Start the 3 point saddle by once more measuring the distance to the obstruction and the height of that obstruction. It is uncommon to make 3 point saddles more than 2 or 3"; for an example we will assume it is 40 inches to the center of the obstruction and that the saddle needs to be 2" high, as if crossing a large conduit.
Mark the conduit at the distance to the obstruction, plus ¼" for each 1" of height. In our example, the mark will be at 40 ½ inches. The extra ½" is to take care of the shrinkage for a 2" tall saddle.
Next, mark the conduit each way from the first mark: 4" for the first inch of height and 6" for each additional inch. In the example, it will now have 3 marks, at 30 ½, 40 ½ and 50 ½ inches (we need 2" of height, requiring marks at 4" + 6", or 10" each way from the first mark). If our obstruction was 3" high we would measure 16" each way from the first mark.
Center the first, center, mark on the custom marked 22° center and make a 22° bend. Slide the conduit forward until the second mark is at the arrow used to bend a 90, rotate the conduit 180° and make a second bend the opposite direction of the first at just over 10°.
Now comes the tricky part that many electricians don't realize. Remove the conduit from the bender, flip it end for end and reinsert it into the bender. Line up the third mark with the same arrow used for the second bend and, bending opposite the first bend once more, make another bend just over 10°.
To recap: the first bend is made with the conduit mark at the customized "center of 22°" mark you made on the bender. Each of the other bends are made with the conduit mark at the normal arrow used for making a 90° bend with the toe of the bender pointed towards the center mark. Conduit marks are made at the center of the obstruction plus ¼" for each inch of height plus a mark each direction from that first mark at 4" for the first inch of height and 6" for each additional inch.
If a saddle of more than 3 or 4 inches is to be made you are probably better off to either use a 4 point saddle or use 45° for the center bend; if the sharper bend is used the saddle usually needs to be considerably taller than the obstruction and the second and third marks are made at 1" for the first inch of height plus 2.6 inches (the multiplier for 22° offsets) for each additional inch. In addition, the second and third bends are made at 22° rather than 10°.
The video shown below demonstrates the method of making a 3 point saddle, although the bends are made far too sharp. This saddle has used 120° of bend already, out of the 360° the NEC allows between pull boxes. Nevertheless it does show the proper method of making the bends and has been included for that reason.
Additional information is available in a "comprehensive guide to conduit bending"; this link will open a new window to the title page with a brief description of each section and links to each.
Bending a 3 Point Saddle in Conduit
Bending a 3 point saddle
© 2011 Dan Harmon