I need Help with a bending radius

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Brian Donlon

Member
Location
Wisconsin
Hi, I need help understanding bending radius.

My question pertains to installing tray cable into a condulet fitting.

For example: I have a 3/c #14 TC with a diameter of .34" what size Tee condulet is required to meet the correct bending radius? If I am understanding this correctly, it is 1 1/4" Tee.

For a 3/c#12 diameter is .49" and if I understand the code correctly it says a 2" condulet? This seems outrageous to me. Can someone please shed some light on this for me?

Thanks!
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Where did you get the conduit body sizes (1.25" and 2") from?

Welcome to the Forum. :)
 
B

Brian Donlon

Member
Location
Wisconsin
infinity said:
Where did you get the conduit body sizes (1.25" and 2") from?

Welcome to the Forum. :)
Click to expand...


I used NEC 336.24 and then a table from Appleton that shows bending radius for their condulets

Here is a part of the table:


LB125-M, -A

K125150-CM, -CA

GK125-150-N

GK125-150-V

LB-125, -A

BC-125G

SGN-125

SG-125

1-A

1-1/4

[FONT=Arial,Arial][FONT=Arial,Arial]1.250
[/FONT][/FONT]
[FONT=Arial,Arial][FONT=Arial,Arial]2.625
[/FONT][/FONT]

LB150-M, -A

K125150-CM, -CA

GK125-150-N

GK125-150-V

LB-150, -A

BC-125G

SGN-125

SG-125

1-A

1-1/2

[FONT=Arial,Arial][FONT=Arial,Arial]1.312
[/FONT][/FONT]
[FONT=Arial,Arial][FONT=Arial,Arial]2.812
[/FONT][/FONT]

LB200-M, -A

K200-CM, -CA

GK200-N

GK-200V

LB-200, -A

BC-200G

SGN-200

SG-200

1-A

2

[FONT=Arial,Arial][FONT=Arial,Arial]1.500
[/FONT][/FONT]
[FONT=Arial,Arial][FONT=Arial,Arial]3.500
[/FONT][/FONT]



I have been part of Tray Cable type installation projects for years. I have never come accross people using these giant fittings for Tray cable installations. It seems so unpractical to run a 3/4" conduit for a 3/c #12 cable and then using a 2" TEE fitting to adhear to a bending radius.. In am aware that I could have been installing this incorrectly over the years, but I have never seen this done by other contractors either and have been to dozens of plants over the last 15 years with these types of installations.
 
B

Brian Donlon

Member
Location
Wisconsin
The last two columns of the table are Bending Radius...



Appleton

Part Number

Cover

Gasket

O-Z/Gedney

Part Number

Cover

Gasket

Figure

Trade size

R1

R2







LB50-M, -A

K50-CM, -CA

GK50-N

GK50-V

LB-50, -A

BC-50G

SGN-50

SG-50

1-A

1/2

0.875

1.500

LB75-M, -A

K75-CM, -CA

GK75-N

GK75-V

LB-75, -A

BC-75G

SGN-75

SG-75

1-A

3/4

0.937

1.750

LB100-M, -A

K100-CM, -CA

GK100-N

GK100-V

LB-100, -A

BC-100G

SGN-100

SG-100

1-A

1

1.000

2.000

LB125-M, -A

K125150-CM, -CA

GK125-150-N

GK125-150-V

LB-125, -A

BC-125G

SGN-125

SG-125

1-A

1-1/4

1.250

2.625

LB150-M, -A

K125150-CM, -CA

GK125-150-N

GK125-150-V

LB-150, -A

BC-125G

SGN-125

SG-125

1-A

1-1/2

1.312

2.812

LB200-M, -A

K200-CM, -CA

GK200-N

GK-200V

LB-200, -A

BC-200G

SGN-200

SG-200

1-A

2

1.500

3.500

 
Smart $

Smart $

Esteemed Member
Location
Ohio
Brian Donlon said:
...

I have been part of Tray Cable type installation projects for years. I have never come accross people using these giant fittings for Tray cable installations. It seems so unpractical to run a 3/4" conduit for a 3/c #12 cable and then using a 2" TEE fitting to adhear to a bending radius.. In am aware that I could have been installing this incorrectly over the years, but I have never seen this done by other contractors either and have been to dozens of plants over the last 15 years with these types of installations.
Click to expand...
Same here.

If the last two columns are bending radii, what does R1 and R2 represent? The bent radius will vary with size and number of the conductors/cables.
 
RichB

RichB

Senior Member
Location
Tacoma, Wa
Occupation
Electrician/Electrical Inspector
Smart $ said:
Same here.

If the last two columns are bending radii, what does R1 and R2 represent? The bent radius will vary with size and number of the conductors/cables.
Click to expand...

My guess would be R1 is short term radi and R2 is long term, ie, fer instance--short term is when pulling and long term is storage after pulling like with FO cable
 
Smart $

Smart $

Esteemed Member
Location
Ohio
Brian Donlon said:
What does permanent training mean?
for R1 and R2?
Click to expand...
In electrical wiring, "training" is the act of positioning [cables]. "Permanent training" refers to the will-not-be-disturbed result.

Still don't explain what R1 and R2 relate to. Got a link to where you got that table (sorry, I'm being lazy at the moment :blink:).
 
B

Brian Donlon

Member
Location
Wisconsin
Bending Radius

Bending Radius

Can someone tell me the correct size standard condulet TEE for these cables then? And how you came up with the answer? I am using the standard Appleton Condulets (Not mogul)



For example: I have a 3/c #14 TC with a diameter of .34" what size Tee condulet is required to meet the correct bending radius? If I am understanding this correctly, it is 1 1/4" Tee.

For a 3/c#12 diameter is .49" and if I understand the code correctly it says a 2" condulet? This seems outrageous to me. Can someone please shed some light on this for me?
 
B

Brian Donlon

Member
Location
Wisconsin
The document

The document

The document I am using is Appleton - O/Z Gedney Conduit Bodies Conductor Bending Radii. (sorry its a paper copy I have. Not sure what the link is)
 
B

Brian Donlon

Member
Location
Wisconsin
Thanks for all the help so far...Maybe you guys could show me what size TEE fittings you guys come up with for these size cables:

a 3/c #14 TC with a diameter of .34"

a 3/c#12 diameter is .49"


Using a standard size TEE condulet (not Mougul)


THANKS!

Smart $ said:
OK, I'll accept that for the purpose of discussion... short of producing the exact document :)

Getting back to the OP issue, 336.24 doesn't stipulate using inside, centerline, or outside bend radius as other Articles do. Which should be used?
Click to expand...
 
B

Brian Donlon

Member
Location
Wisconsin
Bending Radius

Bending Radius

I appreciate everyones help. I would like to see what you guys come up with as far as sizing the correct TEE size for these size cables:

3/c #14 TC with a diameter of .34"

For a 3/c#12 diameter is .49"


[
 
B

Brian Donlon

Member
Location
Wisconsin
So that means for me to route a 3/c #12 awg TC cable with a diameter of .49" I need to use a 2" TEE???


A standard 2" TEE fom appleton has a 1.5" inside radius (Training R1) and a 3.5" outside



This cannot be correct??
 
B

Brian Donlon

Member
Location
Wisconsin
Why would 314.28 apply since it is #12awg conductors in the multi conductor cable.. Are you saying that this article is talking about the diameter of 4 awg wire?


I could tie my shoes with a piece of 3/c #12 TC-ER cable... I cant believe the code requires me to install a 2" Tee for this cable...


infinity said:
Chapter 9 Table 1, note (9) states this:



314.28 states this for conductors sized #4 AWG and larger in boxes and conduit bodies:



IMO the multi-conductor cable in this case is larger than a #4 so it needs to comply with 314.28.
Click to expand...
 
B

Brian Donlon

Member
Location
Wisconsin
I appreciate everyones help... I just can't understand why such large fitting is used for this... Like a said before I have been to dozens of industrial facilites with tray cable installations and I have never seen this practice....
 
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