criss
Member
- Location
- new york city
Am i allowed to run 4- 3/0 and #6 ground wire thru a 2" emt lb???
Where would i find in nec about lb rules
Where would i find in nec about lb rules
Lb,lr, ll, c condalet
- Thread starter criss
- Start date
- Status
- Location
- Massachusetts
Nope.
If you look at a standard 2" conduit body it will say 3 - 4/0s max.
Use a section of 4" x 4" NEMA 1 trough instead of a conduit body or increase the size of the conduit body.
If you look at a standard 2" conduit body it will say 3 - 4/0s max.
Use a section of 4" x 4" NEMA 1 trough instead of a conduit body or increase the size of the conduit body.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Interesting that it is marked on the emt LB's etc, but I have never seen it on a 2" PVC LB. I will have to check more closely. 
- Location
- Illinois
- Occupation
- retired electrician
The only way you can get around the sizing rule in 314.28(A)(2) is if the maximum size and number of conductors is marked on the LB. 314.28(A)(3). This is a rule that is often violated as many assume that the wire fill for a conduit body is the same as the conduit. This is not true for conductors that are #4 and larger.Interesting that it is marked on the emt LB's etc, but I have never seen it on a 2" PVC LB. I will have to check more closely.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I actually looked inside the 2" PVC LB at the supply company and it stated 3-4/0 wires. I guess that means I could put 2- 3/0 and 1- 1/0 with #6 ground. This is what I usually do....
3- 4/0 assuming THHN is equal to .9711 sq. in.
2- 3/0, 1- 1/0 and #6 is equal to .7720 sq. in.
Not sure how to convert since insulation size is not mentioned. Perhaps the insulation would not be needed for the calculation. That seems odd- why not just state max size 4/0 wire and then give a cu.in size allowable.
3- 4/0 assuming THHN is equal to .9711 sq. in.
2- 3/0, 1- 1/0 and #6 is equal to .7720 sq. in.
Not sure how to convert since insulation size is not mentioned. Perhaps the insulation would not be needed for the calculation. That seems odd- why not just state max size 4/0 wire and then give a cu.in size allowable.
Dennis your method may make sense but the stamping states a max of three conductors with a max size of 4/0. There was another thread on this topic that You may want to take a look at. If all your conductors are under #4 than you are not limited to 3 conductors.
Last edited:
K8MHZ
Senior Member
- Occupation
- Electrician
Beside the max size, there is also a max number. You can't put 4 4/0 in the aforementioned LB.
There is also bend radius to consider. A single conductor of .940 (900 kcmil) would be tough to install in a 2 inch PVC lb without damage, if not impossible.
mcclary's electrical
Senior Member
- Location
- VA
I vote impossible
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
- Location
- Illinois
- Occupation
- retired electrician
I don't see where the volume enters into this if the conductor size in #4 or larger. There is nothing in 314.28 to even suggest that the volume of the conduit body or of the conductors is part of the sizing of a conduit body or box used as a pull point for conductors #4 and larger. The only thing that enters into the sizing is the size of the raceway.
I have no idea how you can make a calculation for the use of combination of conductors in a conduit body. I see no issue with using the same number of smaller conductors, but when you want to use more conductors than listed on the fitting, I can't see any permission to make any type of calculation.
I have no idea how you can make a calculation for the use of combination of conductors in a conduit body. I see no issue with using the same number of smaller conductors, but when you want to use more conductors than listed on the fitting, I can't see any permission to make any type of calculation.
- Location
- Illinois
- Occupation
- retired electrician
Then that fitting cannot be used with conductors #4 and larger unless the spacing between the conduit entries meet the requirements in 314.28(A)(2).
You would used the volume to make a calculation as to the permitted number of conductors #6 and smaller based on the conductor volumes found in Table 314.16(B).
- Status