minimum cable bend radius

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hitehm

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Does anyone know if the NEC has a specific formula for minimum cable bend radius less than 600v (not 300.34) and not in a table? I'm going through some poorly written exam prep for my Nevada C-2d and a practice question asks: "What is the minimum bend radius of cable being pulled". The question is pretty vague but the answer they give is "20 times the cable diameter". I have no idea where they got that from or if it's even accurate. In fact the over 600v requirement in 300.34 is only 12X max. Any help is appreciated. Thanks!
 
I did a quick search of the 2014 NEC and found no such reference.

Welcome to the Forum. :)
 
hitehm said:
Does anyone know if the NEC has a specific formula for minimum cable bend radius less than 600v (not 300.34) and not in a table? I'm going through some poorly written exam prep for my Nevada C-2d and a practice question asks: "What is the minimum bend radius of cable being pulled". The question is pretty vague but the answer they give is "20 times the cable diameter". I have no idea where they got that from or if it's even accurate. In fact the over 600v requirement in 300.34 is only 12X max. Any help is appreciated. Thanks!
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I think you may be lumping cables and conductors together.

300.34 is about conductor bending radius. There is no similar requirement for conductors under 600 volts.

On the other hand there are cable bending limitations in the cable articles.

320.24, 326.24, 330.24, 332.24 etc.
 
iwire said:
I think you may be lumping cables and conductors together.

300.34 is about conductor bending radius. There is no similar requirement for conductors under 600 volts.

On the other hand there are cable bending limitations in the cable articles.

320.24, 326.24, 330.24, 332.24 etc.
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Thanks for the replies. I think you may be correct about confusing conductors with cables. The question itself is somewhat confusing because it reads "cables to be pulled" without mentioned the type of cable, which then makes me think of insulated individual conductors (THHN etc) being pulled through a raceway. With that said, do you know of any "cables" that have a bend radius of 20x the diameter?
 
Fiber Optics

Fiber Optics

Some fiber optics have a 15x bend radius - usually an absolute max of 1", although the recommendation is not to exceed a 2" bend radius while pulling. I know of no such reference to a wire bending radius of 20X.
 
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