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wire bending radius

ICE

ICE

Oh Well
Staff member
Joined
Jun 23, 2011
Messages
12,900
Location
California
Shirley there must be a code section for the bending radius of wire. I wrote a correction that asked for a four inch radius. An inspector has challenged me to provide a code section. I don't have a picture of the wire but it must have been too tight so I wrote the correction.

Today I encountered the same violation and that's the pictures here. As you can see there is damage to the insulation. What you can't see is possible damage to the insulation on the other side of the bend. If there is damage there, it is against the metal enclosure. So I can write a correction for the damaged insulation but what about the bending radius. I can bend that size wire just as tight without damage to the insulation.

Section 300.34 is the only place that I have found with a code for wire bending radius but that section applies to over 1000 volts. What I am dealing with is 2/0 wire in service panel enclosures.

The radius here is that of a nickle.

If there is no code it must not be a problem, which suits me just as well.



 
I was guessing at the section Ice I am positive it is in section 300 but do not have a book with me. Try 300.34/ 336 334. 24 the charts are there
 
Sorry no year reference


Bending Radius
Care should be taken not to exceed the bending radius of the cables when routing around corners. According to NEC Article 320.24, for AC cable, the radius of the curve of the inner edge of any bend shall not be less than 5 times the diameter of the cable. NEC Article 330.24(B) states that for MC Cable, the radius shall not be less than 7 times the external diameter of the cable.
 
cda said:
Sorry no year reference


Bending Radius
Care should be taken not to exceed the bending radius of the cables when routing around corners. According to NEC Article 320.24, for AC cable, the radius of the curve of the inner edge of any bend shall not be less than 5 times the diameter of the cable. NEC Article 330.24(B) states that for MC Cable, the radius shall not be less than 7 times the external diameter of the cable.
Click to expand...
But what about a single wire?
 
conduit bodies have depths and dimensions based upon conductor sizing. What size LB would you need for that conductor? That is basically a 90 degree turn
 
Apparently there is no code for the bending radius of individual wires. There are codes for the space provided for bent wire as well as the bending radius of cable but nothing for conductors unless the voltage exceeds 1000 volts.

Live and learn.
 
Mark,
That is the space that the wire occupies. Looking at the pictures there is plenty of space but the wire is not obligated to utilize all of that space.

312.6 Deflection of Conductors.
Conductors at terminals or conductors entering or leaving cabinets or cutout boxes and the like shall comply with 312.6(A) through (C).
(B) Wire-Bending Space at Terminals. Wire-bending space at each terminal shall be provided in accordance with 312.6(B)(1) or (B)(2).

(1) Conductors Not Entering or Leaving Opposite Wall.

Table 312.6(A) shall apply where the conductor does not enter or leave the enclosure through the wall opposite its terminal.

The conductor does not enter or leave the enclosure through the wall opposite its terminal. Therefor there shall be a clear space no less than 3.5" in front of the terminal. That in no way dictates a minimum bending radius for the conductor. Clearly there can be a situation where the maximum radius is limited to that which will fit within a 3.5" clear space in front of a terminal.

This next picture is aluminum wire. I asked for a larger bending radius. I was wrong. I have been getting it wrong for a long time. That's great news as now I will get it right.....for a much shorter time.



Go ahead, beat it with a hammer, just make sure it's a Finish hammer.
 
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The code provides a chart that defines the minimum space allowed in front of a terminal but there is no indication of a minimum width of that space or the radius of bends. The result of that is the work found in these pictures.

Here is a picture that I posted recently on this topic. Nobody contradicted me at that time. I suppose common sense took hold. Well then Shirley, common sense has led me down the wrong path. It's a simple process to revise Tiger code.....no committees.....it passes like corn through a duck.

 
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The insulation damage in the original photo is not because of bending the wire. Rather it is because of the tool used to bend the wire.
 
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