When adding or replacing a shower, you will need to connect the shower drain to the existing drain at home.The new shower drain must be attached to a pipe of the same diameter or larger size.Because most shower drains are 2-Inch drain, looking for an existing pipe with a diameter of 2 inch or larger to connect the new shower drain.For new shower drains, use plastic drains and accessories, whether PVC or ABS.Close the water line of the area you will be working on.Find the existing drain and determine where to connect the new shower drain.If you are connected to a horizontal pipe, you will use wye-Type accessories connected to it.If you cut the drain pipe running vertically like on the wall, use the sanitary teetype fitting.The sanitary tee is more gentle in the side connection than the square or water pipe tee.Using plastic pipes with the same diameter as the existing drain pipe you connect, cut the two pipes 6 inch long.Glue these pieces to each end of the Huai or tee fitting.If you are using a PVC accessory, use a PVC primer and cement to glue the accessory into the accessory.If you use ABS, you only need to use ABS cement without primer.Cut the drain line you connected--You can use a hacksaw if you are cutting plastic pipes.If it is cast iron, please use the cast iron break tool, which can be rented at the tool rental center.If it is a copper pipe, use a steel saw or a electric knife saw, with fine-tooth blade.Cut out a pipe that is 1 inch longer than the total length of the wye or tee combination you stick together.Connect new fittings and pipes to existing pipes with rubber joints.Be sure to twist the new fittings so that the side openings are horizontal and point in the direction you plan to direct the new pipes to the shower drain.By using a screwdriver or 5/16-tighten the steel strip on the rubber connectorInch socket wrench.New Route 2-Inch plastic drain in the direction of shower.The new drain will require 1/4 downhill per straight foot towards a new connection to the building pipe.Remember, water can't flow uphill.Support the new pipe every 4 feet long with a pipe hanger or plumber belt.Connect the shower drain to the pipe vent.According to the local plumbing specifications, the vents usually need to be connected to the shower drain pipe within 42 inch of the shower.Stick the tee to the shower drain so the socket points up.Running ventilation pipes in 1 1/2-Inch diameter plastic pipe from tee to existing pipe vents or mechanical vents.Connect the new drain to the shower with P-Set traps directly below the shower exit.The P-Traps prevent any sewer gas from entering the house from the sewer system.If the trap is accessible later, such as in an open basement, you can use a trap with a Union that allows disassembly to remove any future blockages.If the trap is not accessible, use the trap that is firmly bonded together.