Bending Radius

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splinetto

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Missouri
In certain areas, I am not allowed to come out the back of a 200A meter can with my 4/0 SEU cable. We were told that we dont have enough room and the bend is too tight. The whole bending radius is confusing and I wanted to see if they are right . Can anyone help?
 
There's a bend radius for cables, but not for conductors. Is the skinned out portion of SEU, inside the meter can, still a cable or are they now conductors? This is where the problem comes into play, and I don't know the answer.
 
312.6 (2005)

(if >600 volt, 300.34 - for some reason I always thought 300.34 applied to all conductors, but I couldn't find it in the codebook anywhere else ? )
 
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338.24 Bending Radius. Bends in Types USE and SE cable shall be so made that the cable will not be damaged. The radius of the curve of the inner edge of any bend. during or after installation, shall not be less than five times the diameter of the cable.
...and ditto with what Marc said.
 
splinetto said:
In certain areas, I am not allowed to come out the back of a 200A meter can with my 4/0 SEU cable. We were told that we dont have enough room and the bend is too tight. The whole bending radius is confusing and I wanted to see if they are right . Can anyone help?

I agree with the others that 338.24 only applies to the cables.

However IMO Table 312.6(B) does apply to the conductors and will likely prohibit 4/0 from entering the back of a meter socket just as it often prohibits 4/0 from entering the back of a typical residential panel.

4/0 with one wire per terminal needs 7" of bending space, if it's a lay in lug like a meter socket often is you can reduce the 7" down to 6"
 
mdshunk said:
There's a bend radius for cables, but not for conductors. Is the skinned out portion of SEU, inside the meter can, still a cable or are they now conductors? This is where the problem comes into play, and I don't know the answer.

Manufacturers DO have bending radius limit for conductors, not just for cables.
 
There are cold bend requirements for conductors that comply with UL 44 & 83 (Thermoset-Insulated Wires & Thermoplastic-Insulated Insulated Wires). The wires have to be wrapped around given diameter mandel and not show any cracks in insulation.

Since not all SE cables have one of these wire types then that does not apply. From UL 854 scope

"Type SE cables that are not marked with conductor type letters or are marked with conductor type letters alone ("XHHW", "RHW", or "RHH OR RHW" not followed by "cdrs" or the like) have insulated conductors that do not comply with the Thermoset-Insulated Wires and Cables, UL 44, horizontal flame test."

Lastly, here is an interesting article from Alcan on Flexibility and Springback Characteristics of 600 Volt Insulated Conductors

http://www.cable.alcan.com/NR/rdonl...aracteristicsof600VoltInsulatedConductors.pdf
 
weressl said:
Manufacturers DO have bending radius limit for conductors, not just for cables.

If you could find a radius limit for conductors under 600 volt and listed in Table 310.13 I will be surprised.
 
iwire said:
What conductor type from 310.13 does that link apply to?

1COkoguard-Okolon Type RHH or RHW-2 or USE-2, VW-1 600V Power and Control Cable, Copper Conductor

2BOkonite-Okoseal Type RHW-2/PVC, 600V Power and Control, Copper Conductor

3BOkonite-FMR Type RHH or RHW-2, VW-1, 600V Power and Control Cable, Copper Conductor

4BX-Olene Type RHH or RHW-2 or USE-2, 600V Power and Control Cable, Copper Conductor.

5BX-Olene Type XHHW-2, 600V Power and Control Cable, Copper Conductor.

6BOkoseal-N Type THHN or THWN, VW-1, 600V Power and Control Cable, Copper Conductor.

7BOkozel Type Z and ZW, 600V Power and Control Cable, Copper Conductor.
 
weressl said:
1COkoguard-Okolon Type RHH or RHW-2 or USE-2, VW-1 600V Power and Control Cable, Copper Conductor

2BOkonite-Okoseal Type RHW-2/PVC, 600V Power and Control, Copper Conductor

3BOkonite-FMR Type RHH or RHW-2, VW-1, 600V Power and Control Cable, Copper Conductor

4BX-Olene Type RHH or RHW-2 or USE-2, 600V Power and Control Cable, Copper Conductor.

5BX-Olene Type XHHW-2, 600V Power and Control Cable, Copper Conductor.

6BOkoseal-N Type THHN or THWN, VW-1, 600V Power and Control Cable, Copper Conductor.

7BOkozel Type Z and ZW, 600V Power and Control Cable, Copper Conductor.

Laszlo, where can I find that out?

Where does that sheet reference those conductors?
 
weressl said:
Click on the numbers in front of the text. It will take you to the Okonite catalog/specification sheet.

I saw that. :smile:

What I don't see is anything in writing that links the bending radius sheet to those conductors other then your say so.

Now of course you may be right, but I am a show me kind of guy, where is it written so I can see it?
 
weressl said:
Manufacturers DO have bending radius limit for conductors, not just for cables.
Yes, but the question remains...

In separating conductors of a multiconductor cable for termination must the minimum bending radius of each conductor conform to that required of the "cable" or that of a single conductor???

The NEC does not appear to provide a distinction. In my personal opinion, I believe the individual conductors are not bound to the radius specified for the cable once they pass through a cable connector and routed as single conductors.
 
iwire said:
I agree with the others that 338.24 only applies to the cables.

However IMO Table 312.6(B) does apply to the conductors and will likely prohibit 4/0 from entering the back of a meter socket just as it often prohibits 4/0 from entering the back of a typical residential panel.

4/0 with one wire per terminal needs 7" of bending space, if it's a lay in lug like a meter socket often is you can reduce the 7" down to 6"
I read Table 312.6(A) as requiring a minimum of 4 inches of wire bending space at the terminal. Where and/or how did you come up with 7 [and 6] inches minimum?
 
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Smart $ said:
I read Table 312.6(A) as requiring a minimum of 4 inches of wire bending space at the terminal. Where and/or how did you come up with 7 [and 6] inches minimum?

I was using Table 312.6(B) as we are not coming straight into the lugs.
 
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