RCD (Residual Current Device)
Residual current device RCD consists of a magnetic coil. In the initial state of operation when the switch is closed an i1 current is passing through the coil. When a current passes through the magnetic coil it will get magnetized and a flux will be induced. The working of this RCD will be done in two stages. RCD’s are normally used along with switch boards for providing leakage protection. The magnetic coil is also connected with a load. i1 is the current in the input side and i2 is the current in the second phase or output stage. In the normal working condition both the current produced will be the same and also the flux produced in both the phases will also be same. If any person is affected with shock or else if there is any earth leakage means the current will starts flowing through the load. So the i1= i2+iR i1 – initial current i2 – output current ir – current flowing through the load (leakage current). So as the current flowing through the magnetic coil changes the flux induced in the coil will also changes. So as results the magnetic coil will be get magnetized and the drip coil which is connected with the magnetic coil will also get magnetized and the switch connection will be made open. As a result the supply to the coil will be cut and the person will be safe automatically.
Drainage or Vent System
Drainage system used in a residential building is going to be explained here. It consists of a toilet and a wash basin all are connected with pipelines. The toilet system consists of a closet and a flush tank. When we flush out, the waste water will drained out through the pipelines. An elbow is connected between the drain out pipeline and the main pipeline which is directly connected to the septic tank. Here we are connecting the pipeline in a slope in order to get a smooth movement and to avoid the blocking of waste materials inside the pipeline. In case of the wash basin we are providing a trap in order to avoid the foul smell coming from the septic tank. A readymade in built trap is connected with the toilet system to avoid bad smell. In this piping system we will be having pipelines connected in horizontal run as well as in vertical run. In case of toilet, for connecting pipelines in horizontal and vertical direction we are using a 900 elbow. And in case of the wash basin, connection to the major pipeline from the stack connection is done by using a 450 elbow and also a Y connection is also made instead of a T connection. And also the major pipeline which is connected with all the drainage systems and the septic tank is provided with a slope of ratio 1:100 generally. From both the drainage systems water waste as well as solid waste is producing. Both are coming through their own pipelines and joined with a common pipeline which is going to the septic tank by using a 900 elbow. In order to avoid the foul smell coming out of the septic tank we are providing a vent pipe line. The size of the major pipeline used will be generally of 5 inches. And the connection pipelines used will be generally having a size of 2 inches.