Someone recently asked me if there’s a way to bend PVC conduit or if someone makes a bender or a tool to get a proper bend. In this episode we’re going to cover how I do it.
When working with PVC conduit electricians do one of two things when bends are involved. Either:
1) we will buy “manufactured bends” like pre-bent “90’s, 45’s, and 30’s”
2) we will use a heat gun to manually bend the conduit to fit the application.
Manufactured bends are often sold in the same aisle as the PVC conduit itself, and come in several angles. However, sometimes the job requires a slightly trickier bend to be made so we need to do it by hand. Often times pre-manufactured bends are too large, or create too small of an offset so it’s time to break out the heat gun!
To bend PVC you need to have either a high-powered blow dryer or an actual “heat gun” at your disposal. These can be bought online or at your local Home Depot. The model I have (and prefer) is a Wagner Furno 750. It has a digital display and will heat up to 750watts. Not only can you hold it like a gun to heat the conduit, but you can set it upright on the ground and roll the pipe with both hands. Not many models out there have this functionality.
The second thing to have nearby when bending conduit is a bottle of water or a hose. When heating PVC conduit it becomes very maleable, but it does not stay in the position you bend it without waiting quite awhile - while holding it in the desired position. One way to speed the drying process up is by splashing cool water on the PVC to set it instantaneously.
Bending A 90
A 90 is probably the most involved thing you could bend using PVC pipe and a heat source. The reason is that you need to overheat the amount of pvc that you’re going to bend. I try to heat 6-8 inches of pipe evenly when bending a 90, as the total 90 will be roughly 5” in from beginning to outer edge. I slowly heat the entirety of what I intend to bend, and begin applying pressure to bend the pvc. I bend at multiple points until I get the pvc flexible enough to start forming a 90, and continue heating any stiff areas that are not loosening up. Finally once I get the shape I want, I pour some water on the pipe to rapidly cool the material - locking the shape in instantly.
Bending An Offset
Step 1 - Measure Your Offset
The first thing we need to know is how far away from the wall our pipe is. This is the “gap” that we need to reduce to get our conduit laying flush on the wall. In my example my conduit is 3 inches from the wall. This means we need this conduit to move 3 inches, or more specifically we need to make 2 bends that offsets the distance between the pipes. If you have a specific height you need from where the conduit emerges from grade to, lets say, an outlet box mounted on the wall - DON’T WORRY ABOUT THE LENGTH….yet. We’ll get to this in a minute. For now we’re only concerned with the offset.
Step 2 - Mark Your Offsets
When bending an offset in a piece of conduit you need to make your bends at very specific points. It doesn’t matter if you’re using EMT, Rigid, PVC, or IMC - all types of conduits use these same method for bending. There is a mathematical standard that we electricians use to figure out where these points are.
A 3 inch offset is going to take up 6 inches of pipe so I need to plan where I start my first bend. Too close to the end of the pipe and it’ll be impossible to bend, or will likely kink when trying to bend it. Too close to the box we’re trying to land in and we may not get a connector (male-adapter) on the pipe. In my example I chose 3 inches from the end of the pipe and mark that spot with a marker or a pencil.
Step 3 - Heat The Conduit
Using the heat gun heat a large surface area of pipe. Generally I like to heat 3 inches on either side of my mark for a 90, or a specific marked spot if I’m doing an offset, box offset, or kick. Once you get the material flexible, bend roughly a 30 degree bend and pour water on it to lock it in place. Then back up to your second bend and repeat this process. Always stick a tape-measure at the end of your pipe to check and make sure your offset will clear the obstacle. Reheat to make any adjustments necessary.
That’s it, its much more forgiving than bending hard EMT (electrical metallic tubing), so its a great place to start if you want to practice bending offsets to see, structurally, how it works. Please leave comments if you have any questions!
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**Disclaimer - These videos are for training purposes alone, all work done on electrical systems should be done by a licensed and insured electrical contractor. If you are not an electrician, do not attempt any of the work you are seeing in these videos.**