knight1fox3
Member
Hello,
I currently work in the material handling industry, specifically in the area of electrical design for overhead cranes and hoists. One of the steps in our design process is to provide an electrical calculation for the crane electrical system. This calculation serves as a reference for how we size specific components and conductors for the crane electrical system.
My question pertains to which sections of NEC take precedence over the other when sizing mainline conductors and branch conductors (for a crane & hoist application). Our typical designs utilize variable frequency drives and squirrel-cage AC induction motors. I recently attended a 2-day seminar for NEC 2008. I asked the instructor about this and he indicated that Table 310.16 should be used for the sizing of the mainline and distribution conductors feeding the variable frequency drives. The conductors between the VFD and the motor should be sized using Table 610.14(A). I wanted to get feedback from a few others to see if this is the proper way to apply the NEC code. Furthermore, I also wanted to see how I might go about getting an official NEC statement confirming that my methods are correct. A sample single-line (one-line) diagram of a crane electrical system layout can be viewed here. Let me know if there are any questions or if I need to provide additional information. I appreciate any feedback, thank you.
I currently work in the material handling industry, specifically in the area of electrical design for overhead cranes and hoists. One of the steps in our design process is to provide an electrical calculation for the crane electrical system. This calculation serves as a reference for how we size specific components and conductors for the crane electrical system.
My question pertains to which sections of NEC take precedence over the other when sizing mainline conductors and branch conductors (for a crane & hoist application). Our typical designs utilize variable frequency drives and squirrel-cage AC induction motors. I recently attended a 2-day seminar for NEC 2008. I asked the instructor about this and he indicated that Table 310.16 should be used for the sizing of the mainline and distribution conductors feeding the variable frequency drives. The conductors between the VFD and the motor should be sized using Table 610.14(A). I wanted to get feedback from a few others to see if this is the proper way to apply the NEC code. Furthermore, I also wanted to see how I might go about getting an official NEC statement confirming that my methods are correct. A sample single-line (one-line) diagram of a crane electrical system layout can be viewed here. Let me know if there are any questions or if I need to provide additional information. I appreciate any feedback, thank you.