Conductor Bending Radius

[ritelec]

I'm trying to understand max bending radius for conductors relating 300.34 and the tables in the back for approximate diameter.
I remember a discussion years ago where someone came out of the back of a 200 amp meter pan (single phase 3 wire) and a comment was made that that size wire was a violation of bending radius.
The person who did the install said he used a box adapter (attached) and there for the radius was good.
Since that time, I've always made it a point to come out of the bottom of a meter pan to avoid any issues. Yet, as I look around as I'm driving I see tons of 200 amp services with nothing coming out of the bottom of the meter pan. SO, I assume they're all coming out of the back of the meter pan.
Are they all installed using box adapters or are inspectors just not catching it or just letting it go ( kinda like I see all these exposed service conductors in driveways in schedule 40 and not sch 80 or emt or rmc)?
Is the box adapter ok for not having to use a bushing?
Looking around you tube I can't find anything for USA conductor bending radius videos to help explain this and how I would measure from where the conductor enters to the terminal or opposite end of a box.
Can any one here easily explain it?


For instance, If I use 4/0 seu al. I would go to the table for thhn,thwn,thwn-2 (table 5) which has an approximate diameter of .642. So 8 (from 300.34) x .642 (from table 5) = 5.136 What do I do with this number ?

xhhw-2 has a approximate diameter of .638

Would I measure from where the conductor comes out from the bushing to the terminal in a straight line and it can't be closer than 5.136"? Is this it or am I way off.

I will continue looking.

Thank you

 

[infinity]

300.34 Is for over 1000 volts so from your description it appears that this sections does not apply to your installation.

 

[ritelec]

Right you are.
312.6


table 312.6(A)

column 1 "All other" or column 2 Compact stranded ?
wires per terminal, 1 4/0 4 in.

would that mean then 4" minimum from bushing to terminal?


or am I to look at table 312.6(B) 7b" ?

Thank you

 

[ritelec]

Would load side terminals of meter to back wall be 312.6 (B)(1)?,
and load side of terminals of meter to bottom wall be 312.6(B)(2)?

(I do notice exception No.2 meter sockets)

 

[ritelec]

Would load side terminals of meter to back wall be 312.6 (B)(1)?, therefore a min of 4"
and load side of terminals of meter to bottom wall be 312.6(B)(2)? therefore 7b"

(I do notice exception No.2 meter sockets) so that would be 4" min ?

 

[jim dungar]

There are no general minimum bending radii given in the NEC for <1000v installations.
However, the NEC does have minimums for the distance between a lug/termination and an enclosure wall. These 'wire bending' dimensions include the bending radii of the conductor as well as enough room to be able to insert the conductor into the lug/termination.

 

[paulengr]

There are no general minimum bending radii given in the NEC for However, the NEC does have minimums for the distance between a lug/termination and an enclosure wall. These 'wire bending' dimensions include the bending radii of the conductor as well as enough room to be able to insert the conductor into the lug/termination.

The cable manufacturers all specify minimums. It would be a violation to ignore manufacturers instructions. Kind of like using the wrong wire combination in a wire nut.

But those tables are very reasonable. I’ve had to deal with many panels that violated it. Installers will feed the cable in a straight run working it from the other end of the raceway. Then when it comes time to replace the breaker you can’t get it out or in, sort of like a pipe with no unions.

 

[don_resqcapt19]

The cable manufacturers all specify minimums. It would be a violation to ignore manufacturers instructions. Kind of like using the wrong wire combination in a wire nut.
...

When you read those, they are manufacture's recommendations and they are not 110.3(B) instructions.

 

[ritelec]

However, the NEC does have minimums for the distance between a lug/termination and an enclosure wall.

Thank you.
Is the dimension solely based on the distance from the lug/termination to the enclosure wall only. Or will the distance decreased by the threads of a installed connector and bushing ?

 

[infinity]

Thank you.
Is the dimension solely based on the distance from the lug/termination to the enclosure wall only. Or will the distance decreased by the threads of a installed connector and bushing ?

The distance is for the enclosure to the terminals, where/how the conduit enters does not matter.

 

[ritelec]

Thank you.