Cable Sizing and Selection Introduction: One of the important aspects of designing any electrical system is to select an appropriate type and size of a cable. Too much small size of cable generates a lot of heat in a cable which will caused permanent damage to an insulation of a cable and using a too much large cable size means we are wasting our money on copper because copper is the costly material for cables. So we must have to select a cable that is neither of too small nor too large size. Further there are many types of cable like stranded cable, ACSR, PVC insulation etc. Cable sizing helps us to select an accurate size (i.e. cross sectional area) and type of cable required for a particular system. Why …show more content…
Frequency of current when we are dealing with alternating current. Heat dissipation ability of a cable Ambient temperature or surrounding temperature: The greater the ambient or surrounding temperature the lesser heat will be required to reach the maximum temperature rating of insulation. Cable’s Insulation temperature rating: The amount of heat generated in the cable should not exceed the maximum temperature rating of an insulation of a cable Conductor size: the larger the conductor size the greater will be the current carrying capacity of a cable. Conductor grouping: if the numbers of conductors that are grouped together are increased the heat dissipation will be lesser. Base ampacities: Cable manufacturer will specify the base ampacities of cable for specific type of the cable construction (i.e. the material used for cable, insulation of cable, operating voltage of cable, etc) and a base set of installation (i.e. the ambient or surrounding temperature of cable, the cable is placed in conduit or raceway …show more content…
For a DC system: The formula for a calculation of voltage drop for a dc system is same as that for single phase ac system except that in single phase ac system resistance and reactance both are present but in dc system there is no reactance so for the calculation of voltage drops we only have to consider the resistance of the cable. Voltage drop= 2* Current* Resistance*Length/1000 Vdc = 2*I*R*L/1000 Where, Vdc is the dc voltage drop in volts I is the full load current in
Materials of different types will exhibit varied changes in temperature when transferred the same amount of heat. This variation is a result of the difference in properties displayed from one material to another, known as "heat capacity." Every substance has a variable, positive valued heat capacity that represents the amount of heat required to initiate a specific temperature change. (Hechinger, page 1) For ideal gases, there are heat capacities at constant volume and constant pressure given by:
Warm Potato: that when the potato is warmed but not heated over 35 degrees (due to high temperature will...
The thermometer’s original temperature before coming in contact with an outside object is represented by T. ∆T/∆t is the average temperature of the digital thermometer. represents the temperature of the heat flowing object. In this lab, the temperature of the air is represented by Tair=T. To= Thand is the temperature of the hand.
on how long it takes to heat up. If we heat a large volume of water it
is 37°C and as soon as you go above this temperature it will cause the
The module AC/DC is directly related to the career path of the electrical linemen. In the module i learned about two types of electrical current, alternating (AC), and direct current (DC). In direct current (DC), the electric charge (current) only flows in one direction. Electric charge in alternating current (AC), on the other hand, changes direction periodically. The voltage in (AC) circuits also periodically reverses because the current changes direction. Electrical lineman work on power lines and other thing that have (AC) or (DC) current depending on what they are working on. Lineman work on electrically energized (live) and de-energized (dead) power line. They may perform a number of tasks associated with power lines, including installation or replacement of distribution equipment such as capacitor banks, distribution transformers on poles, insulators and fuses.
5) Objects above this three to four foot line show signs of heat damage (melted candles, cracked mirrors, etc.); objects below this line show o damage.
Also, when we put the insulation cans in warn water the water heated up the can. And lastly, in the insulated can experiments, both cooling and heating, when the cans temperature was changed it in turn changed the air temperature
The importance of an electrical lineman is huge, not only in the community but also in most of the world. Their education, training, and correct use of equipment help them in their different and dangerous work conditions to accomplish the tasks of providing power to their communities.
Aim: To find out what type of insulation holds the most heat for a can
Since early 2003 the Electrical Inspectorate has been working to raise public awareness of Residual Current Devices (RCDs), with the aim of eventually enforcing the use of these devices as recommended by the standard adopted by the St. Lucia Bureau of Standards for wiring of buildings SLNS/BS 7671: 2001- Requirements for Electrical Installations ¡V IEE Wiring Regulations ¡V Sixteenth Edition. These Regulations though only recently adopted by the Bureau of Standards is the Regulations referred to by the St. Lucia Electricity regulations of 1973 as the standard of wiring of buildings. For a very long time the cost of these devices had proven prohibitive for the enforcement of the requirement. However, it is now believed that safety concerns as it relates to electrical hazards such as fire and electrocution far outweigh the cost of these devices
...distances then Direct Current which range from the power source to the house and then back to the power source for example. The average in an American house is about 60 hertz times in one second. Alternating current travels from the power source where the electricity is generated to your house in a hot line, once it arrives to the house, and then it looks for a resting state and finds in in a neutral line, that's how it makes its way back home.
...k again. Inspectors do this because over time the electricity passing through a bad wire damages the wire even more in can result in a fire. The fire could cost the owner lots of money in repairs or on appliances and furniture.
Thermal death point (TDP) is the temperature at which a culture of organism is killed within a short...
to work because it will not be at the optimum temp, or it will not