![]() Never try replacing the wires and outlets on your own, especially when you do not have any basic knowledge or experience regarding this job. Ask the local electrical inspector of your area for rules regarding wire specification for the type of wire and its application. You should check whether the wire is rated for direct burial underground or not. The wire should be used according to the National Electrical Code (NEC) electrical wire specification. The environment, temperature rating and the application of the wire should be considered when selecting the appropriate wire specification and wire type. The information on wire specifications should be based on the insulation of the wire and its temperature ratings. The hanging live wire inside the control panel may get too hot causing the insulation to melt and lead to a fire hazard. Thus, this increase in current causes the wire to break off that may lead to a serious complication. The wire becomes smaller and there is increase in heat. This makes the stranded wire lose its strands one at a time and the solid wire to become brittle. The continuous high temperature running through the wire causes corrosive effect at the terminal connections of the wire. ![]() This melts the insulation around the wire that can lead to a dangerous situation. If the current is fast and the wire size small, the wire will get heated up too soon. The current ratings of the power loads is the factor that is to be considered when determining the wire size and wire specifications. Importance of Wire Size The primary consideration to be taken before wiring a new circuit is the wire size and wire type. You should consult the expert that is your local electrician and find out what is required and legal in your area. One needs to consider the voltage drop, insulation temperature limit, thickness, thermal conductivity, air convection and temperature. You should follow the Handbook of Electronic Tables and Formulas for American Wire Gauge to refer to electronic wire sizing chart. Table of Wire Size Requirements You need to follow a wire chart table that will serve as a guideline of ampacity or copper wire current carrying capacity. So according to the formula: VDI= (10 × 50)/2 × 22) = 500 ÷ 44 = 11.36 Thus, for the copper wire, according to the table the nearest VDI is 12. NFPA 70®, National Electrical Code® and NEC® are registered trademarks of the National Fire Protection Association, Quincy, MA.For Example: 10 Amp load at 22V for a distance of 50 feet with 2% max. This reprinted material is not the complete and official position of the NFPA on the referenced subject, which is represented only by the standard in its entirety. * Reprinted with permission from NFPA 70®-2014, National Electrical Code®, Copyright © 2013, National Fire Protection Association, Quincy, MA. Table 1: TABLE 310.15(B)(3)(a) Adjust Factors for More Than Three Current-Carrying Conductors The count shall not include conductors that are connected to electrical components but that cannot be simultaneously energized. The count shall be adjusted in accordance with 310.15(B)(5) and (6). Number of conductors is the total number of conductors in the raceway or cable, including spare conductors. Percent of Values in Table 310.15(B)(16) through 310.15(B)(19) as Adjusted for Ambient Temperature if Necessaryġ. *TABLE 310.15(B)(3)(a) Adjustment Factors for More Than Three Current-Carrying Conductors
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