Unusual and strange code questions

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MPdesign

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Here are a few unusual and strange code questions.

If you recommend anyone who is best at answering these, please do and I will contact them directly as I do have this type of need somewhat regularly. I don't mind paying for help when I need it.

1) Is there anything in the NEC code that talks about a minimum wire bending radius? I cannot find anything.

2) Where in the code does it show or mention that super 88 is allowed (for the most common uses)? I know it will not be directly mentioned - but where is it indirectly approved?

Thank you for your insight. Have a great weekend!
 
hmmm, i think #1 is covered by NEC when it states that wire is to be used as specified by the manufacturer, which covers about everything NEC applies to, etc.

most name brand wire vendors have a min bend radius spec to prevent the insulation from ripping on the short side of the bend. for some wire alloys the min bend radius also protects the wire itself from forming cracks from the stress incurred from bending.
 
MPdesign said:
Here are a few unusual and strange code questions.

If you recommend anyone who is best at answering these, please do and I will contact them directly as I do have this type of need somewhat regularly. I don't mind paying for help when I need it.

1) Is there anything in the NEC code that talks about a minimum wire bending radius? I cannot find anything.

2) Where in the code does it show or mention that super 88 is allowed (for the most common uses)? I know it will not be directly mentioned - but where is it indirectly approved?

Thank you for your insight. Have a great weekend!
Click to expand...

1. Conductors at terminals-312.6. Cables-3XX.24

2. 110.14(B) sorta.

All splices and joints and the free ends of conductors
shall be covered with an insulation equivalent to that of
the conductors or with an identified insulating device.
 
MPdesign said:
Here are a few unusual and strange code questions.

If you recommend anyone who is best at answering these, please do and I will contact them directly as I do have this type of need somewhat regularly. I don't mind paying for help when I need it.

1) Is there anything in the NEC code that talks about a minimum wire bending radius? I cannot find anything.

2) Where in the code does it show or mention that super 88 is allowed (for the most common uses)? I know it will not be directly mentioned - but where is it indirectly approved?

Thank you for your insight. Have a great weekend!
Click to expand...

The answer to #1 is going to depend on the specific application- there is 300.34 that applies to conductors over 1000v, and there are other bending articles that apply to cables see 330.24, 342.24 etc....

The answer to number 2 can lie with 110.14(B) -among others- it all has to do with putting insulation equivalent to the other insulation a wire, and whether or not such tape is listed for the use, and if it is applied per manufacturers instructions-see 110.3(B).

And when we look at what super 88 is listed/identified for, we see that it will work for wire/splice insulation.:)
 
For > 600v 300.34 ('11 Code) addresses bending radius. For conductors in general probably 312.6 is useful.
For Super 88, I would think the best the Code will do is in 110.3
 
MPdesign said:
...
2) Where in the code does it show or mention that super 88 is allowed (for the most common uses)?...
Click to expand...
Perhaps I've been in the trade too long. Why would anyone even think Super 88 is not allowed? :blink:

...or are we getting into uber specifics like application temperature rating?
 
Thank you all!

Here is another one. You guys are really impressive.

Does a hub like this need plastic bushings? Why not? Where is it allowed in the code?
Hub.jpg
 

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MPdesign said:
...Does a hub like this need plastic bushings? Why not?
Click to expand...
How are you going to put one on?

Plastic bushings are typically not required. What is required is the conductors be protected from abrasion. A rounded, bur-free edge is usually sufficient.
 
MPdesign said:
Thank you all!

Here is another one. You guys are really impressive.

Does a hub like this need plastic bushings? Why not? Where is it allowed in the code?
Click to expand...

300.4(G) Insulated Fittings. Where raceways contain 4 AWG
or larger insulated circuit conductors, and these conductors
enter a cabinet, a box, an enclosure, or a raceway, the conductors
shall be protected by an identified fitting providing
a smoothly rounded insulating surface, unless the conductors
are separated from the fitting or raceway by identified
insulating material that is securely fastened in place.

Exception: Where threaded hubs or bosses that are an
integral part of a cabinet, box, enclosure, or raceway provide
a smoothly rounded or flared entry for conductors.
 
jumper said:
1. Conductors at terminals-312.6. ...
Click to expand...
While that section requires a specific amount of bending space at terminations, it does not specify a minimum bending radius for the conductors. You are just required to have the space to make the bends, but not required to use that space.

Sorry Jim....posted without reading the complete thread .
 
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