Required Clearance for 2.5" conduit LB

[philly]

I have an enclosure that I want to come out of and would like to use an LB to route the conductor out of the enclosure and along the wall. The conductors are (2) sets of parallel 3/c 4/0 cables routed in a 2.5" conduit. I would like to come out of the enclosure with these conductors through an LB and the route the cables in a 2.5" conduit along the wall.

My first question is can a 2.5" LB be used for these conductors? I'm not sure if this adheres to 314.28?

Secondly how much space is required for the installation of the 2.5" LB. The enclosure only sits 8" from the wall so there is only 8" between the side of the enclosure where the cables are leaving and the wall. Is this enough room to install a 2.5" LB or do I need to move this enclosure away from the wall more? Is there a code section that specifies this clearance?

 

[don_resqcapt19]

You will have to look at the information from the manufacturer or that marked on the fitting to know if that fitting is suitable for that size cable. See 314.28(A)(3).

 

[RichB]

Also I think I would go with an LL or LR, depending on which side of the enclosure you are coming out of--8" isn't much room to work in.

 

[philly]

You will have to look at the information from the manufacturer or that marked on the fitting to know if that fitting is suitable for that size cable. See 314.28(A)(3).

The information I have shows the fitting has 200 cubic feet capacity. How do I use this to determine if this is suitable for the cable?

Using the LB to go out and up the LB would be 6.13" from the enclosure to the face of the LB" This would not leave much room but could it possibly work? Is there a requirement on the amount of room or simply just a maintnance standpoint?

May flex work better?

 

[kingpb]

Using the O.D. of a Southwire 3/C #4/0AWG cable which is 1.508", the minimum bend radius of cable is 5 x O.D. = 7.54".

Looking at Crouse Hinds LR or LL dimensions a 2.5" will not meet the min bend requirements because it is only 4.5 inches wide. You would need an LL or LR (LB is not good) that has a body that is approximately 5.6" wide. Even a 4" with reducers won't quite work unless you can find a 3/C cable that has an O.D. of 1.46".

May need to consider a J-Box, or use 1/C cable. A 1/C #4/0 AWG O.D. is around 0.624", and requires a 4x minimum bend radius, which is 2.5". This should not be an issue, because a 2.5" LL or LR can handle 3-1/C x 300KCMIL.

If you have 8" space, using a 2.5" LL or LR should leave you about 1.5" to spare, but you need to use 1/C cable to achieve this.

 

[philly]

Using the O.D. of a Southwire 3/C #4/0AWG cable which is 1.508", the minimum bend radius of cable is 5 x O.D. = 7.54".

Looking at Crouse Hinds LR or LL dimensions a 2.5" will not meet the min bend requirements because it is only 4.5 inches wide. You would need an LL or LR (LB is not good) that has a body that is approximately 5.6" wide. Even a 4" with reducers won't quite work unless you can find a 3/C cable that has an O.D. of 1.46".

May need to consider a J-Box, or use 1/C cable. A 1/C #4/0 AWG O.D. is around 0.624", and requires a 4x minimum bend radius, which is 2.5". This should not be an issue, because a 2.5" LL or LR can handle 3-1/C x 300KCMIL.

If you have 8" space, using a 2.5" LL or LR should leave you about 1.5" to spare, but you need to use 1/C cable to achieve this.

Out of curiosity where did you get these bending radius's from? Are these standard or are these specific per manufacturer?

Is this the only thing we need to consider or do we need to take 314.28 into consideration?

If the bending radius is the only issue then it sounds like we can use a 1/c cable?

 

[philly]

Using the O.D. of a Southwire 3/C #4/0AWG cable which is 1.508", the minimum bend radius of cable is 5 x O.D. = 7.54".

Looking at Crouse Hinds LR or LL dimensions a 2.5" will not meet the min bend requirements because it is only 4.5 inches wide. You would need an LL or LR (LB is not good) that has a body that is approximately 5.6" wide. Even a 4" with reducers won't quite work unless you can find a 3/C cable that has an O.D. of 1.46".

May need to consider a J-Box, or use 1/C cable. A 1/C #4/0 AWG O.D. is around 0.624", and requires a 4x minimum bend radius, which is 2.5". This should not be an issue, because a 2.5" LL or LR can handle 3-1/C x 300KCMIL.

If you have 8" space, using a 2.5" LL or LR should leave you about 1.5" to spare, but you need to use 1/C cable to achieve this.

Also why are you saying to use an LL or LR and that an LB is no good?

 

[philly]

One other thing. If I use a pull box is the 8" enough to comply with 314.28. What size conduit would you size the 6x required distance between the enclosure and wall off of since there is no conduit in the enclosure?

 

[kingpb]

Also why are you saying to use an LL or LR and that an LB is no good?

The design of the LB is such that the depth of the fitting would not support the 3/C cable. I believe it would be OK with the 1/C cable. However, with the limited 8" of space I think the LL or LR would be easier to work with.

The bending radius is fairly standard, the cable I looked at is a 3/C and 1/C THHN by Southwire. I don't think any of the manufacturer's will be that much different. As far as radius, it comes from the Southwire Installation guide for 600V cable. You can download it off their website. It has excellent info in it.

If you look at 314.28 (A) (3) you will see that they can be smaller provided the manufacturer has permanently marked the fitting with the number and maximum size of conductors.

In that regard, I think your safe with the 2.5" fitting, either LB (not SLB) LL, or LR.

 

[don_resqcapt19]

The information I have shows the fitting has 200 cubic feet capacity. How do I use this to determine if this is suitable for the cable? ...

You can't, for that size wire the volume has nothing to do with the issue. The fitting has to be marked with the maximum number and size of conductors that it is listed to be used with.

 

[don_resqcapt19]

The design of the LB is such that the depth of the fitting would not support the 3/C cable. I believe it would be OK with the 1/C cable. However, with the limited 8" of space I think the LL or LR would be easier to work with. ...

I would never even think about trying a LL or LR for that size wire. It is much more difficult to get wire of an size around a LR or LL than it is an LB.

 

[kingpb]

I would never even think about trying a LL or LR for that size wire. It is much more difficult to get wire of an size around a LR or LL than it is an LB.

One man's utopia is another man's dystopia, herr comrad.................

 

[philly]

I think I may decide to go with a pull box as suggested. I will mount the pull box on the side of the enclosure between the enclosure and wall and them will have the conduits coming out of the top of the box.

Is the 8" between the enclosure and wall with a pull box enough for the cable bending radius and requirements of 314.28?

I will have (4) 2.5" conduits coming out of the top of the box so do I need to take 314.28 into consideration when determining the height of the box?

Thanks