How to Layout an EMT Electrical Conduit
The term conduit is frequently used to describe any system containing electrical conductors. However, this is only a general description. An electrical conduit is, specifically, a piping system that is used to protect electrical wiring. It can be made out of any variety of materials (such as plastic, clay, or fiber), but EMT conduits are among the most commonly used. Galvanized steel tubing conduits (GRC) are most often used commercially, but EMT is more commonly used because it is cheaper and lighter, although it cannot be threaded. The following article will guide you through the process of installing EMT electrical conduits.
Step 1 - Cutting the Tubing
A vise is highly recommended. Although you can certainly opt to cut your tubing without using a vise, it makes the process much simpler, and these instructions will be assume that you have chosen to use a vise. Whether you choose to use a vise or not, you must use a hacksaw that has at least 18 teeth per inch. If it has fewer teeth, it will not cut very efficiently, and may even break. Once you have chosen a blade, place it in the hacksaw frame so that the teeth are pointing outwards. Place your pipe in the vise. When placing it in the vise, be sure that there is plenty of room between the vise and where you will be making the cut. This will make your job much simpler. Once you have placed the pipe, you can begin sawing. Use a steady, light pressure. Do not try to force the saw or place a great deal of pressure on it. Be patient and allow the saw to do its job.
Step 2 - Bending the Conduit
In order to install your EMT conduit, you will in all likelihood have to bend it. It must be bent without the inner diameter of the conduit being reduced, and you must be able to bend it yourself. There are two kinds of tools you can use to bend conduits: the rigid bender and the EMT bender. For this guide, the EMT bender is recommended. It is designed for use with EMT electrical conduits, and can easily make even severe 90 degree bends. For the purpose of this step, we are going to make a bend in a conduit that extends from the ceiling to the floor.
Your first step is to determine where on your conduit the bends will have to be made. Measure from where the conduit will need to bend (in this case, the ceiling), and make a mark at this point in the conduit. After marking this point, find the take-up length of your conduit. The take-up length is determined based on the width of your conduit. For example, 1/2-inch EMT has a 5 inch take-up. So if you are working with 1/2-inch EMT, your second make will be made 5-inches down from your first mark.
When you have made both marks, hold the bender so that the side with the lip is touching the ground. Position the lip under the pie at your take-up mark, with the footrest of the bender being closer to the first mark. Once your EMT and bender are in position, apply steady pressure with your foot. The bender has degree marks on it, so you can see when you can stop bending. In this case, you can stop once you have a 90 degree angle.
Step 3 - Installing the Conduit
Your conduit must be installed before your conductors are installed, so it is important that you install it correctly. Although EMT conduits can be fitted for either dry or moist locations, we are going to run through how to install them in dry locations. Here, the most important part is getting the fittings right.
Place your plain sleeve over the ends that you need to join. Make indents in the coupling and tubing with your indenting tool. This is how you secure the joint. You will use the indenting tool twice at each end of the coupling. When installing your EMT conduit, it will need to be supported. EMT conduits (and other conduits made of flexible metal) must be supported at intervals of at most 4.5 feet. However, if the run is less than 3 feet long, or requires extra flexibility, the intervals can be greater. When connecting light fixtures, you can add supports at intervals of up to 6 feet.